ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (154)
  • Universitätsverlag Göttingen  (116)
  • American Association of Petroleum Geologists (AAPG)
  • American Chemical Society
  • American Institute of Physics (AIP)
  • Copernicus
  • 2020-2022
  • 2010-2014  (154)
Collection
Publisher
Language
Years
Year
  • 1
    Publication Date: 2020-07-31
    Description: Numerical tools are essential for the prediction and evaluation of conventional hydrocarbon reservoir performance. Gas hydrates represent a vast natural resource with a significant energy potential. The numerical codes/tools describing processes involved during the dissociation (induced by several methods) for gas production from hydrates are powerful, but they need validation by comparison to empirical data to instill con fidence in their predictions. In this study, we successfully reproduce experimental data of hydrate dissociation using the TOUGH+HYDRATE (T+H) code. Methane(CH4)hydrate growth and dissociation in partially water- and gas-saturated Bentheim sandstone were spatially resolved using Magnetic Resonance Imaging (MRI), which allows the in situ monitoring of saturation and phase transitions. All the CH4 that had been initially converted to gas hydrate was recovered during depressurization. The physical system was reproduced numerically, usingboth a simplified 2D model and a 3D grid involving complex Voronoi elements. We modeled dissociation using both the equilibrium and the kinetic reaction options in T+H, and we used a range of kinetic parameters for sensitivity analysis and curve fitting. We successfully reproduced the experimental results, which confirmed the empirical data that demonstrated that heattransport was the limiting factor during dissociation. Dissociation was more sensitive to kinetic parameters than anticipated, which indicates that kinetic limitations may be important in short-term core studies and a necessity in such simulations. This is the first time T+H has been used to predict empirical nonmonotonic dissociation behavior, where hydrate dissociation and reformation occurred as parallel events.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2020-04-23
    Description: The current difficulty in visualizing the true extent of malignant brain tumors during surgical resection represents one of the major reasons for the poor prognosis of brain tumor patients. Here, we evaluated the ability of a hand-held Raman scanner, guided by surface-enhanced Raman scattering (SERS) nanoparticles, to identify the microscopic tumor extent in a genetically engineered RCAS/tv-a glioblastoma mouse model. In a simulated intraoperative scenario, we tested both a static Raman imaging device and a mobile, hand-held Raman scanner. We show that SERS image-guided resection is more accurate than resection using white light visualization alone. Both methods complemented each other, and correlation with histology showed that SERS nanoparticles accurately outlined the extent of the tumors. Importantly, the hand-held Raman probe not only allowed near real-time scanning, but also detected additional microscopic foci of cancer in the resection bed that were not seen on static SERS images and would otherwise have been missed. This technology has a strong potential for clinical translation because it uses inert gold-silica SERS nanoparticles and a hand-held Raman scanner that can guide brain tumor resection in the operating room.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2016-09-16
    Description: Electrolytes can thermodynamically inhibit clathrate hydrate formation by lowering the activity of water in the surrounding liquid phase, causing the hydrates to form at lower temperatures and higher pressures compared to their formation in pure water. However, it has been reported that some thermodynamic hydrate inhibitors (THIs), when doped at low concentrations, could enhance the rate of gas hydrate formation. We here report a systematic study of model natural gas (a mixture of 90% methane and 10% propane) hydrate formation in strong monovalent salt solutions in a broad range of concentrations, using a high pressure automated lag time apparatus (HP-ALTA). HP-ALTA can apply a large number (〉100) of cooling ramps to a sample and construct probability distributions of gas hydrate formation for each sample. The probabilistic interpretation of data enables us to mitigate the stochastic variation inherent in the nucleation probability distributions and facilitates meaningful comparison among different samples. The electrolytes used in this work are lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), sodium chloride (NaCl), sodium bromide (NaBr), sodium iodide (NaI), potassium chloride (KCl), potassium bromide (KBr), and potassium iodide (KI). We found that (1) some salts may act as kinetic hydrate promoters at low concentrations; (2) the width of the probability distributions (stochasticity) of natural gas hydrate formation in these salt solutions was significantly narrower than that in pure water. To gain further insight, we extended the study of the solutions of the same nine salts to the formation of ice and model tetrahydrofuran (THF) hydrate for comparison.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    In:  Journal of Renewable and Sustainable Energy, 6 (1). Art.-Nr.: 013116.
    Publication Date: 2021-06-23
    Description: Eutrophication combined with climate change has caused ephemeral filamentous macroalgae to increase and drifts of seaweed cover large areas of some Baltic Sea sites during summer. In ongoing projects, these mass occurrences of drifting filamentous macroalgae are being harvested to mitigate eutrophication, with preliminary results indicating considerable nutrient reduction potential. In the present study, an energy assessment was made of biogas production from the retrieved biomass for a Baltic Sea pilot case. Use of different indicators revealed a positive energy balance. The energy requirements corresponded to about 30%–40% of the energy content in the end products. The net energy gain was 530–800 MJ primary energy per ton wet weight of algae for small-scale and large-scale scenarios, where 6 000 and 13 000 tonnes dwt were harvested, respectively. However, the exergy efficiency differed from the energy efficiency, emphasising the importance of taking energy quality into consideration when evaluating energy systems. An uncertainty analysis indicated parametric uncertainty of about 25%–40%, which we consider to be acceptable given the generally high sensitivity of the indicators to changes in input data, allocation method, and system design. Overall, our evaluation indicated that biogas production may be a viable handling strategy for retrieved biomass, while harvesting other types of macroalgae than red filamentous species considered here may render a better energy balance due to higher methane yields.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    American Chemical Society
    In:  In: Physical Methods in Food Analysis. American Chemical Society, Washington, DC, pp. 105-125. ISBN 9780841228856
    Publication Date: 2016-08-30
    Description: Consumer preference for natural food ingredients has increased in recent decades, and the natural food colorant market has grown to over one billion dollars annually. A variety of red, orange, and yellow natural colorants are approved and in use, but there still exists a lack of available blue and purple natural colorant options. The occurrence of blue colored compounds in the natural world is relatively rare. The isolation, identification, and characterization of natural blue and purple pigments obtained from underexplored natural sources such as from obscure terrestrial organisms and marine microorganisms will be discussed.
    Type: Book chapter , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2020-05-11
    Description: Two new natural products, 3 and 4, and their predecessor 7-isocyanoisoneoamphilecta-1(14),15-diene (2), of the rare isoneoamphilectane class of marine diterpenes, along with the known amphilectane diterpenes 6–8, were isolated from the n-hexane extract of the marine sponge Svenzea flava collected at Great Inagua Island, Bahamas. The molecular structures of compounds 3 and 4 were established by spectroscopic (1D/2D NMR, IR, UV, HRMS) methods and confirmed by a series of chemical correlation studies. In a first ever case study of the assignment of the absolute configuration of a molecule based on the isoneoamphilectane carbon skeleton, the absolute configuration of compound 5 was established as 3S,4R,7S,8S,11R,12S,13R by application of vibrational circular dichroism (VCD). In vitro anti-TB screenings revealed that metabolites 2–4 and, in particular, semisynthetic analogue 5, are strong growth inhibitors of Mycobacterium tuberculosis H37Rv.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2020-07-21
    Description: Chemicals targeting the liver stage (LS) of the malaria parasite are useful for causal prophylaxis of malaria. In this study, four lichen metabolites, evernic acid (1); vulpic acid (2), psoromic acid (3), and, (+)-usnic acid (4), were evaluated against LS parasites of Plasmodium berghei. Inhibition Of P. falciparum blood Stage (BS) parasites was also assessed to determine stage specificity. Compound 4 displayed the highest LS activity and stage specificity (LS IC50 value 2.3 mu M, BS IC50 value 47.3 mu M). The compounds 1 - 3 inhibited one Or more enzymes (Pf FabI, PfFabG, and pfFabZ), from the Plasmodial fatty acid biosynthesis (FAS-II) pathway, a potential drug. target for LS activity. To determine species specificity and to clarify the mechanism of reported antibacterial effects, 1-4 were also evaluated against FabI homologues and Whole cells of various pathogens -(S. aureus, E. coli M. tuberculosis). Molecular modeling studies suggest that lichen acids act indirectly via binding to allosteric sites on the protein surface of the FAS-II enzymes. Potential. toxicity, of compounds was assessed in human hepatocyte and cancer cells (in vitro) as well as in a zebrafish model (in vivo):. This study indicates the therapeutic and prophylactic potential of lichen metabolites as antibacterial and antiplasmodial agents.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Abstracts of Papers of the American Chemical Society, 245 . 173-GEOC.
    Publication Date: 2016-04-21
    Type: Article , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Analytical Chemistry, 85 (6). pp. 3271-3279.
    Publication Date: 2014-06-17
    Description: New indicators for optical CO2 sensors are synthesized in two steps from the commercially available diketo-pyrrolo-pyrrole (DPP) pigments Irgazin Ruby and Irgazin Scarlet. After introduction of bis(2-ethylhexyl) sulfonamide groups via a simple two-step synthesis, the pigments are rendered highly soluble in organic solvents and in polymers and show pH-dependent absorption and emission spectra. The new indicators have molar absorption coefficients in a 20 000–50 000 M–1 cm–1 range, possess quantum yields close to unity, and feature good photostability. The indicators along with a quaternary ammonium base are embedded into ethyl cellulose to give optical carbon dioxide sensors. The absorption and emission spectra of the deprotonated form are bathochromically shifted by more than 100 nm compared to the neutral form (λmax absorption 496–550 nm; λmax emission 564–587 nm). This enables colorimetric read-out and self-referenced ratiometric fluorescence intensity measurements. Importantly, the dynamic range of the sensors based on the new indicators is significantly different (0–10 kPa and 1–100 kPa CO2) that enables a broad variety of applications. New DPP dyes are conveniently prepared from commercially available pigments and represent a new class of colorimetric and fluorescent pH indicators for optical carbon dioxide sensors.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Journal of Agricultural and Food Chemistry, 61 (24). pp. 5792-5797.
    Publication Date: 2021-02-22
    Description: Undaria pinnatifida, commonly known as wakame in Japan, is one species of brown seaweeds containing valuable bioactive organic compounds such as fucoxanthin, a carotenoid, which has numerous functional properties. However, most of the seaweeds that do not meet strict quality standards are normally discarded as wastes or returned to the sea, a situation which is becoming an environmental concern. In this research, supercritical carbon dioxide (SCCO2) extraction was investigated for the isolation of fucoxanthin. SCCO2 extraction experiments were carried out at temperature range of 25–60 °C and pressure range of 20–40 MPa, at a carbon dioxide flow rate of 1.0–4.0 mL/min. Results showed that fucoxanthin recovery closed to 80% could be obtained at 40 °C and 40 MPa in extraction time of 180 min. The recovery increased with decreasing temperature and increasing pressure. Pretreatment with microwave (MW) also enhanced the efficiency of extraction due most likely to disruption of the cell membrane. Application of SCCO2, generally regarded as safe and environmentally benign solvent, for extraction of useful bioactive compounds from unwanted or substandard seaweeds look promising in the near future. The extracts obtained using the method can be utilized as food and pharmaceutical additive, and can be used in the development of new health supplements.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Abstracts of Papers of the American Chemical Society, 243 . 536-ENVR.
    Publication Date: 2017-10-24
    Type: Article , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2020-05-11
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    facet.materialart.
    Unknown
    American Chemical Society
    In:  The Journal of Physical Chemistry A, 115 (46). pp. 13324-13331.
    Publication Date: 2020-05-11
    Description: Microscopy, confocal Raman spectroscopy and powder X-ray diffraction (PXRD) were used for in situ investigations of the CO2-hydrocarbon exchange process in gas hydrates and its driving forces. The study comprises the exposure of simple structure I CH4 hydrate and mixed structure II CH4–C2H6 and CH4–C3H8 hydrates to gaseous CO2 as well as the reverse reaction, i.e., the conversion of CO2-rich structure I hydrate into structure II mixed hydrate. In the case of CH4–C3H8 hydrates, a conversion in the presence of gaseous CO2 from a supposedly more stable structure II hydrate to a less stable structure I CO2-rich hydrate was observed. PXRD data show that the reverse process requires longer initiation times, and structural changes seem to be less complete. Generally, the exchange process can be described as a decomposition and reformation process, in terms of a rearrangement of molecules, and is primarily induced by the chemical potential gradient between hydrate phase and the provided gas phase. The results show furthermore the dependency of the conversion rate on the surface area of the hydrate phase, the thermodynamic stability of the original and resulting hydrate phase, as well as the mobility of guest molecules and formation kinetics of the resulting hydrate phase.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2012-11-14
    Description: Earthquake history shows that the Sunda subduction zone of the Indonesian margin produces great earthquakes offshore Sumatra, whereas earthquakes of comparable magnitude are lacking offshore Java and the Lesser Sunda islands. Morphological structures from multibeam bathymetric data across the forearc relate with the extent of the seismogenic zone (SZ). Off Java and the Lesser Sunda islands the Indo-Australian plate subducts almost normal underneath the oceanic plate of the Indonesian archipelago. Landward of the trench, the outer wedge of the slope break is ~50 km uniformly wide with uniform bathymetric gradients. The slope of the outer wedge is locally cut by one/two steeper ridges of ~5 km extent. The sharp slope break corresponds to the updip limit of the SZ, which is also associated with the seawardmost part of the outer arc high. Landward of the slope break we find narrow, uniform outer arc ridges. The landward termination of these ridges coincides with the downdip limit of the SZ. The intersection of the shallow upper plate mantle with the subduction thrust fault marks the downdip limit of the SZ beneath the forearc. Off Sumatra the Indo-Australian plate subducts obliquely underneath the continental part of the Indonesian Sunda margin. Landward of the trench, the outer wedge varies, being mostly ~70 km wide, in some areas narrowing to 50 km width. The lower slope bathymetric gradients are steep. The outer wedge slope is made up of several steeper ridges of ~5 km extent. The slope break is only locally sharp, and corresponds to the updip limit of the SZ. The outer arc ridges off Sumatra are, in comparison with the forearc structures off Java and the Lesser Sunda islands, wider and partly elevated above sea level forming the Mentawai forearc islands. The downdip limit of the SZ coincides with the intersection of a deeper upper plate mantle with the subduction thrust fault beneath the forearc. Sunda Strait marks a transition zone between the Sumatra and Java margins. Seafloor morphology enables the identification of the seismogenic zone (SZ) across the entire Sunda margin. The SZ is uniformly wide for the Sumatra margin and narrows off Sunda Strait. Sunda Strait is the transition between the Sumatra margin and the uniformly narrow extent of the SZ of the Java/Lesser Sunda margin. Comparing the Java and Lesser Sunda islands with the Sumatra margin we find the differences along the Sunda margin, especially the wider extent of the SZ off Sumatra, producing larger earthquakes, to result from the combination of various causes: The sediment income on the oceanic incoming plate and the subduction direction; we attribute a major role to the continental/oceanic upper plate nature of Sumatra/Java influencing the composition and deformation style along the forearc and subduction fault. Off Sumatra the SZ is up to more than twice as wide as off Java/Lesser Sunda islands, enlarging the unstable regime off Sumatra and thus the risk of sudden stress release in a great earthquake.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria ; p. 407 .
    Publication Date: 2012-07-06
    Description: EGU2011-407 The spatial and temporal distribution of sea ice in the subpolar North Atlantic is mainly controlled by the advection of warm Atlantic Water via the Norwegian and West Spitsbergen Current in eastern Fram Strait. Simultaneously, polar water and sea ice from the Arctic Ocean is transported southward by the East Greenland Current. Hence, variations in the strength of this oceanic circulation regime may either stimulate or reduce the sea ice extent. Based on organic geochemical studies of a high-resolution sediment core from eastern Fram Strait we provide new evidence for the highly variable character of the sea ice conditions in this area. The combination of the sea ice proxy IP25 (Belt et al., 2007) with phytoplankton derived biomarkers (e.g. brassicasterol, dinosterol; Volkman 2006) enables a reliable reconstruction of sea surface and sea ice conditions, respectively (Müller et al., 2009; 2010). By means of these biomarkers, we trace gradually increasing sea ice occurrences from the Mid to the Late Holocene – consistent with the neoglacial cooling trend. Throughout the past ca. 3,000 years (BP) we observe a significant short-term variability in the biomarker records, which points to rapid advances and retreats of the sea ice cover at the continental margin of West Spitsbergen. The co-occurrence of IP25 and phytoplankton markers, however, suggests that the primary productivity benefits from these sea ice surges. As such, higher amounts of open-water phytoplankton biomarkers together with peak abundances of IP25 indicate recurring periods of enhanced ice-edge phytoplankton blooms at the core site. To what extent a seesawing of temperate Atlantic Water may account for these sea ice fluctuations requires further investigation. Concurrent variations in Siberian river discharge (Stein et al., 2004) or Norwegian glacier extents (Nesje et al., 2001), however, strengthen that these fluctuations may be assigned to variations in the North Atlantic/Arctic Oscillation (NAO/AO) and (hence) a weakened/accelerated Atlantic Water input and Arctic sea ice export.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2012-07-06
    Description: The upwelling area in the eastern equatorial Pacific off Peru is one of the most pronounced oxygen minimum zones (OMZs) of the modern ocean. Modeling scenarios predict an expansion of the OMZs in the course of global change in the coming decades. As a consequence, the Peruvian continental margin represents a key locality for studies on biogeochemical dynamics in the future ocean. We present pore water and sediment data for redox-sensitive metals (Fe, Mn, V, Mo, and U) that have been collected along a transect across the Peruvian margin at 11°S. The results are used to evaluate the behavior of trace metals in a wide range of biogeochemical and hydrodynamic settings. In the core of the OMZ, where permanently anoxic conditions prevail, redox sensitive metals exhibit diagenetic behaviors largely consistent with previous studies. Vanadium and Mo are released from Fe oxihydroxides and subsequently recycled through diffusion across the benthic boundary or trapped through formation of authigenic V phases and sequestration of Mo by authigenic pyrite. Some U is delivered through diffusion across the benthic boundary, reduction and precipitation of UO2 and incorporation into phosphorites. The utmost part of the buried U, however, is delivered in particulate form, most likely as bioauthigenic U which cannot be recycled in the suboxic waters overlying the anoxic sediments. In contrast to sediments in the core of the OMZ, sediments on the shelf experience frequent oxygenation episodes related to the passage of internal waves and the regular recurrence of El Niño events. These oxygenation episodes lead to the re-oxidation and remobilization of authigenic U and V. In contrast to that, the authigenic accumulation of Mo is favored by the occasional occurrence of slightly oxidizing conditions. This is most likely due to enhanced formation of sulfur intermediates necessary for pyrite formation and the increased stability of pyrite, the major Mo sink, under oxidizing conditions, compared to authigenic V and U phases. Redox oscillations in the Peruvian OMZ thus lead to a discrimination of U against Mo, a mechanism that should be considered in the interpretation of U/Mo systematics in paleo redox studies. Overall our results provide valuable constraints on how trace metal inventories of marginal sediments may respond to expanding shelf anoxia and to short term perturbations of sediment redox conditions.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2020-05-11
    Description: Calculations of the size and density of atmospheric aerosols are complicated by the fact that they can exist at concentrations highly supersaturated with respect to dissolved salts and supercooled with respect to ice. Densities and apparent molar volumes of solutes in aqueous solutions containing the solutes H2SO4, HNO3, HCl, Na2SO4, NaNO3, NaCl, (NH4)2SO4, NH4NO3, and NH4Cl have been critically evaluated and represented using fitted equations from 0 to 50 °C or greater and from infinite dilution to concentrations saturated or supersaturated with respect to the dissolved salts. Using extrapolated densities of high-temperature solutions and melts, the relationship between density and concentration is extended to the hypothetical pure liquid solutes. Above a given reference concentration of a few mol kg−1, it is observed that density increases almost linearly with decreasing temperature, and comparisons with available data below 0 °C suggest that the fitted equations for density can be extrapolated to very low temperatures. As concentration is decreased below the reference concentration, the variation of density with temperature tends to that of water (which decreases as temperature is reduced below 3.98 °C). In this region below the reference concentration, and below 0 °C, densities are calculated using extrapolated apparent molar volumes which are constrained to agree at the reference concentrations with an equation for the directly fitted density. Calculated volume properties agree well with available data at low temperatures, for both concentrated and dilute solutions. Comparisons are made with literature data for temperatures of maximum density. Apparent molar volumes at infinite dilution are consistent, on a single ion basis, to better than ±0.1 cm3 mol−1 from 0 to 50 °C. Volume properties of aqueous NaHSO4, NaOH, and NH3 have also been evaluated, at 25 °C only. In part 2 of this work (ref 1) an ion interaction (Pitzer) model has been used to calculate apparent molar volumes of H2SO4 in 0−3 mol kg−1 aqueous solutions of the pure acid and to represent directly the effect of the HSO4− ↔ H+ + SO42− reaction. The results are incorporated into the treatment of aqueous H2SO4 density described here. Densities and apparent molar volumes from −20 to 50 °C, and from 0 to 100 wt % of solute, are tabulated for the electrolytes listed in the title and have also been incorporated into the extended aerosol inorganics model (E-AIM, http://www.aim.env.uea.ac.uk/aim/aim.php) together with densities of the solid salts and hydrates.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Journal of Agricultural and Food Chemistry, 59 (18). pp. 9916-9921.
    Publication Date: 2020-07-27
    Description: A total of 19 naturally occurring bromophenols, with six new and 13 known structures, were isolated and identified from the methanolic extract of the marine red alga Rhodomela confervoides. The new compounds were identified by spectroscopic methods as 3,4-dibromo-5-((methylsulfonyl)methyl)benzene-1,2-diol (1), 3,4-dibromo-5-((2,3-dihydroxypropoxy)methyl)benzene-1,2-diol (2), 5-(aminomethyl)-3,4-dibromobenzene-1,2-diol (3), 2-(2,3-dibromo-4,5-dihydroxyphenyl)acetic acid (4), 2-methoxy-3-bromo-5-hydroxymethylphenol (5), and (E)-4-(2-bromo-4,5-dihydroxyphenyl)but-3-en-2-one (6). Each compound was evaluated for free radical scavenging activity against DPPH (α,α-diphenyl-β-dipicrylhydrazyl) and ABTS [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt] radicals. Most of them exhibited potent activities stronger than or comparable to the positive controls butylated hydroxytoluene (BHT) and ascorbic acid. The results from this study suggest that R. confervoides is an excellent source of natural antioxidants, and inclusion of these antioxidant-rich algal components would likely help prevent the oxidative deterioration of food.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2013-02-28
    Description: EGU2011-12780 A temporary passive seismic network of 31 broad-band stations was deployed in the region around Talca and Constitución between 35°S to 36°S latitude and 71°W to 72.5°W longitude. The network was operated between March and October 2008. Thus, we recorded data prior the magnitude Mw=8.8 earthquake of 27 February 2010 at a latitude of the major slip and surface uplift. The experiment was conducted to address fundamental questions on deformation processes, crustal and mantle structures, and fluid flow. We present results of a teleseismic P receiver function study that covers the coastal region and reaches to the Andes. The aim is to determine the structure and thickness of the continental crust and constrain the state of hydration of the mantle wedge. The P-wave receiver function technique requires large teleseismic earthquakes from different distances and backazimuths. A few percent of the incident P-wave energy from a teleseismic event will be converted into S-wave (Ps) at significant and relatively sharp discontinuities beneath the station. A small converted S phase is produced that arrives at the station within the P wave coda directly after the direct P-wave. The converted Ps phase and their crustal multiples contain information about crustal properties, such as Moho depth and the crustal vp/vs ratio. We use teleseismic events with magnitudes mb 〉 5.5 at epicentral distances between 30° and 95° to examine P-to-S converted seismic phases. Our preliminary results provide new information about the thickness of the continental crust beneath the coastal region in Central Chile. At most of the stations we observed significant energy from P to S converted waves between 4 and 5 s after the direct P-wave within a positive phase interpreted as the Moho, occurring at 35 to 40 km. The great Maule earthquake of 27 February 2010 nucleated up-dip of the continental Moho. The rupture of this earthquake seems to have propagated down-dip of the Moho. The Moho reflection show a positive polarity, indicating that the mantle is either dry or only moderately hydrated. We observed converted energy from an intracrustal boundary at around 2 s that disappears near the coast. Further, positive polarity peaks occur that are possibly caused by the down going plate.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Publication Date: 2019-09-23
    Description: EGU2011-8738 At present, the Arctic is responding faster to global warming than most other areas on earth, as indicated by rising air temperatures, melting glaciers and ice sheets and a decline of the sea ice cover. As part of the meridional overturning circulation which connects all ocean basins and influences global climate, northward flowing Atlantic Water is the major means of heat and salt advection towards the Arctic where it strongly affects the sea ice distribution. Records of its natural variability are critical for the understanding of feedback mechanisms and the future of the Arctic climate system, but continuous historical records reach back only ca. 150 years. To reconstruct the history of temperature variations in the Fram Strait Branch of the Atlantic Current we analyzed a marine sediment core from the western Svalbard margin. In multidecadal resolution the Atlantic Water temperature record derived from planktic foraminifer associations and Mg/Ca measurements shows variations corresponding to the well-known climatic periods of the last millennium (Medieval Climate Anomaly, Little Ice Age, Modern/Industrial Period). We find that prior to the beginning of atmospheric CO2 rise at ca. 1850 A.D. average summer temperatures in the uppermost Atlantic Water entering the Arctic Ocean were in the range of 3-4.5°C. Within the 20th century, however, temperatures rose by ca. 2°C and eventually reached the modern level of ca. 6°C. Such values are unprecedented in the 1000 years before and are presumably linked to the Arctic Amplification of global warming. Taking into account the ongoing rise of global temperatures, further warming of inflowing Atlantic Water is expected to have a profound influence on sea ice and air temperatures in the Arctic.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    facet.materialart.
    Unknown
    Copernicus
    In:  [Poster] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria .
    Publication Date: 2012-07-06
    Description: EGU2011-1847-3 Lake Van is a lake by volume of 607 km3 and a maximum depth of 450 meters in a tectonically active zone in eastern Anatolia, Turkey. In summer 2010, Lake Van was the target of a deep drilling campaign (PaleoVan) in the frame of ICDP (International Continental Scientific Drilling Program). Two sites were drilled based on reflection seismic data collected during a seismic campaign in 2004. Here we present a first joint interpretation of the seismic and drilling data. Interpretation of seismic reflection data from lake reveals three physiographic provinces: a lacustrine shelf, a lacustrine slope, and a deep, relatively flat lake basin. The most prominent features of the lacustrine shelf and slope are prograding deltaic sequences, numerous unconformities, submerged channels, as well as closely spaced U- and/or V-shaped depressions, reflecting the variable lake level history of Lake Van. The seismic units of the shelf are dominantly composed of low-to-good continuity, variable amplitude reflections interpreted as fluvial deposits. The lake consists of three prominent basins (Tatvan, Deveboynu, and Northern Basins), separated by basement highs or ridges (Ahlat Ridge). The seismic units corresponding to these basins mainly consist of low to very high amplitude, well-stratified reflection patterns. Chaotic reflections are seen in parts of these basins. The Deveboynu Basin consists mainly of chaotic reflections. The Tatvan and Northern Basins are characterized by an alternating succession of well-stratified and chaotic reflecting layers. The chaotic seismic facies are interpreted as slump and slide deposits, which are probably the result of quick lake level fluctuations and/or earthquakes. The moderateto high amplitude, well-stratified facies seen in the deep parts of the basins away from the terrigenous sediment sources are interpreted as lacustrine deposits and tephra layers. The total sediment thickness in the deep parts of the lake is over 400 m. Prominent clinoforms indicate the initial flooding of Lake Van about 500 ka ago. The acoustic basement and the sediments lying on top of the basement in the southern part of the lake are disrupted by various intrusions and extrusions suggesting active volcanism. Synthetic seismograms calculated based on core logging, wire-line logging and check shot data will allow the correlation between seismic and drill data. This approach will allow extrapolating the stratigraphy from the wells to 3D-space by using the seismic data.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2014-12-23
    Description: EGU2011-4235 The Arctic is undergoing rapid environmental and economic transformations. Recent climate warming, which is simplifying access to oil and gas resources, enabling trans Arctic shipping, and shifting the distribution of harvestable resources, has brought the Arctic Ocean to the top of national and international political agendas. Scientific knowledge of the present status of the Arctic Ocean and the process-based understanding of the mechanics of change are urgently needed to make useful predictions of future conditions throughout the Arctic region. These are required to plan for the consequences of climate change. A step towards improving our capacity to predict future Arctic change was undertaken with the Second International Conference on Arctic Research Planning (ICARP II) meetings in 2005 and 2006, which brought together scientists, policymakers, research managers, Arctic residents, and other stakeholders interested in the future of the Arctic region. The Arctic in Rapid Transition (ART) Initiative developed out of the synthesis of the several resulting ICARP II science plans specific to the marine environment. This process started in October 2008 and has been driven by early career scientists. The ART Initiative is an integrative, international, multi-disciplinary, long-term pan-Arctic network to study changes and feedbacks with respect to physical characteristics and biogeochemical cycles in the Arctic Ocean in a state of rapid transition and its impact on the biological production. The first ART workshop was held in Fairbanks, Alaska, in November 2009 with 58 participants from 9 countries. Workshop discussions and reports were used to develop a science plan that integrates, updates, and develops priorities for Arctic Marine Science over the next decade. The science plan was accepted and approved by the International Arctic Science Committee (IASC) Marine Group, the former Arctic Ocean Science Board. The second ART workshop was held in Winnipeg, Canada, in October 2010 with 20 participants from 7 countries to develop the implementation plan. Our focus within the ART Initiative will be to bridge gaps in knowledge not only across disciplinary boundaries (e.g., biology, geochemistry, geology, meteorology, physical oceanography), but also across geographic (e.g., international boundaries, shelves, margins, and the central Arctic Ocean) and temporal boundaries (e.g., alaeo/geologic records, current process observations, and future modeling studies). This approach of the ART Initiative will provide a means to better understand and predict change, particularly the consequences for biological productivity, and ultimate responses in the Arctic Ocean system. More information about the ART Initiative can be found at http://aosb.arcticportal.org/art.html.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    facet.materialart.
    Unknown
    Copernicus
    In:  [Poster] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria .
    Publication Date: 2012-07-06
    Description: EGU2011-13199 Images of crustal construction provide a key to understand the interplay of magmatism and tectonism while oceanic crust is build up. Bathymetric data show that the crustal construction is highly variable. Areas that are dominated by magmatic processes are adjacent to areas that are highly tectonised and where mantle rocks were found. The Mid-Atlantic Ridge at 22°N shows this high variability along the ridge axis, within the TAMMAR segment, and from segment to segment. However, this strong variability occurs also off-axis, spreading parallel, representing different times in the same area of the ridge. A fracture zone, with limited magma supply, has been replaced by a segment centre with a high magmatic budget. Roughly 4.5 million years ago, the growing magmatic active TAMMAR segment, propagated into the fracture zone, started the migration of the ridge offset to the south, and stopped the formation of core complexes. We present data from seismic refraction and wide-angle reflection profiles that surveyed the crustal structure across the ridge crest of the TAMMAR segment. These yield the crustal structure at the segment centre as a function of melt supply. The results suggest that crust is ~8 km thick near the ridge and decreases in thickness with offset to the ridge axis. Seismic layer 3 shows profound changes in thickness and becomes rapidly one kilometre thicker approx. 5 million years ago. This correlates with gravimetric data and the observed “Bull’s eye” anomaly in that region. Our observations support a temporal change from thick lithosphere with oceanic core complex formation to thin lithosphere with focussed mantle upwelling and segment growing. The formation of ‘thick-crust’ volcanic centre seems to have coincided with the onset of propagation 4.5 million years ago.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria ; p. 6081 .
    Publication Date: 2012-07-06
    Description: EGU2011-6081 Natural stable isotopes are a powerful tool in marine sciences to investigate biological processes, such as present and past nutrient utilization. In this study we present the first dissolved silicon isotope data in the upwelling area off Peru, where one of the world’s largest Oxygen Minimum Zones (OMZ) is located. Silicon is the most important component required for phytoplankton (diatom) growth, which dominates primary productivity in this region. Stable Si isotopes are fractionated during diatom growth in that the lighter Si isotopes are preferentially incorporated into diatoms with a fractionation factor of -1.1 promille. The Si isotope composition of dissolved silicic acid of the corresponding surface waters is therefore left isotopically heavier. The Si isotope composition, 30Si/28Si, is expressed as δ30Si values, which stand forh deviations from a given standard (NBS28). Investigation of the dissolved seawater Si isotope composition thus provides a measure for the utilization and, combined with information on the Si isotope composition of the water masses upwelling off Peru, it is a measure for the supply pathways of Si to the coastal upwelling centres. Surface waters on the shelf off Peru are mainly fed by the Equatorial Undercurrent, which mainly consists of waters originating from the western and Central Pacific and which has a characteristic δ30Si of +1.5 promille. In areas and during phases of intense upwelling the fractionation of Si isotopes was observed to be weaker due to upwelling-driven supply of less fractionated Si (δ30Si = 1.7 promille, from water depths of around 100-150 m, whereas under weak upwelling conditions fractionation is higher (δ30Si ~3 promille due to a more complete utilization of the available dissolved silicate. The distribution of dissolved δ30Si correlates strongly with particulate biogenic silicate (opal) concentrations in that highest opal concentrations in the surface waters show the lowest δ30Si values thus strongest upwelling intensity. The most extreme δ30Si values in surface waters (δ30Si = 4.5 promille are observed offshore where silicic acid concentrations are nearly zero. Furthermore we compare the δ30Si data with the dissolved nitrogen isotope distribution, which in addition to nitrate utilization is mainly influenced by denitrification and annamox processes in the OMZ. Combined silicon and nitrogen isotope compositions can thus help to disentangle different fractionation processes within the nitrogen cycle.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    Copernicus
    In:  [Poster] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria ; p. 2455 .
    Publication Date: 2012-07-06
    Description: EGU2011-2455 The current interglacial has gone through a variety of warmer and colder periods. Consistent with the decreasing solar insolation during the Holocene, warmest conditions have occurred particularly within its earliest phase. We studied high-resolution sediment sequences from the Western Svalbard margin covering the last ca 10,000 years in order to reconstruct the variations of Atlantic Water advection to the Arctic, the sea ice extent, and the structure of the water column on the Westspitsbergen continental margin. The Fram Strait, often referred to as the Arctic Gateway, is the only deep-water passage for Atlantic-derived water masses to enter the Arctic Ocean. Northward advection of relatively warm and saline Atlantic Water masses keeps the eastern part of the Fram Strait ice-free all year. It therefore plays a crucial role for the heat budget of the Arctic. A multiproxy data set including geochemical, micropaleontological, and sedimentological parameters was established with centennial to multidecadal time resolution. Records of foraminiferal oxygen and carbon isotopes, planktic foraminifer assemblages, and the amount of ice rafted debris clearly reveal distinct variations between climatically warmer and colder intervals throughout this period. Planktic foraminifer assemblages reveal warmest conditions for the early Holocene period (ca 10-8 ka). A second warming pulse is detected between 5 and 6 ka. In the second half of the Holocene, increased IRD contents are indicative of a significant cooling trend. Despite of the decreasing solar insolation planktic foraminiferal assemblages suggest a return of slightly strengthened Atlantic Water advection around 3 to 2 ka and a strong warming event in the present, anthropogenically influenced period.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2011, 03.04.-08.04.2011, Vienna, Austria ; p. 3514 .
    Publication Date: 2012-07-06
    Description: We determined the isotopic composition of neodymium (Nd) and lead (Pb) of past seawater to reconstruct water mass exchange and erosional input between the Arctic Ocean and the Norwegian-Greenland Seas over the past 5 Ma. For this purpose, sediments of ODP site 911 (leg 151) located at 900 m water depth on the Yermak Plateau in the Fram Strait were used. The paleo-seawater variability of Nd and Pb isotopes was extracted from the sea water-derived metal oxide coatings on the sediment particles following the leaching method of Gutjahr et al. (2007). All radiogenic isotope data were acquired by Multi-Collector (MC) ICP-MS. The site 911 stratigraphy of Knies et al. (2009) was applied. Surface sediment Sr and Nd isotope data, as well as downcore Sr isotope data obtained on the same leaches are close to seawater and confirm the seawater origin of the Nd and Pb isotope signatures. The deep water Nd isotope time series extracted from site 911 was in general more radiogenic ("Nd = -7.5 to -10) than present day deep water ("Nd = -9.8 to -11.8) in the area of the Fram Strait (Andersson et al., 2008) and does not show a systematic trend with time. In contrast, the radiogenic isotope composition of Pb evolved from 206Pb/204Pb ratios around 18.7 to more radiogenic values around 19.2 between 2 Ma and today. The data indicate that mixing of water masses from the Arctic Ocean and the Norwegian-Greenland Seas has controlled the Nd isotope signatures of deep waters on the Yermak Plateau over the past 5 Ma. Prior to 1.7 Ma the Nd isotope signatures on the Yermak Plateau were less radiogenic than waters from the same depth in the central Arctic Ocean (Haley et al., 2008) pointing to a greater influence from the Norwegian-Greenland Seas. After 1.7 Ma the central Arctic and Yermak Plateau data have varied around similar values indicating water mass mixing overall similar to today. In contrast, the Pb isotope composition of deep waters in the Fram Strait appears to have been dominated by weathering inputs from glacially weathering old continental landmasses, such as Greenland or parts of Svalbard since 2 Ma. A similar control over the Pb isotope evolution of seawater since the onset of Northern Hemisphere Glaciation was recorded by ferromanganese crusts that grew from North Atlantic DeepWater in the western North Atlantic. References: Gutjahr, M., Frank, M., Stirling, C.H., Klemm, V., van de Flierdt, T. and Halliday, A.N. (2007): Reliable extraction of a deepwater trace metal isotope signal from Fe-Mn oxyhydroxide coatings of marine sediments.- Chemical Geology 242, 351-370 Haley B. A., M. Frank, R.F. Spielhagen and A. Eisenhauer (2008): Influence of brine formation on Arctic Ocean circulation over the past 15 million years. Nature Geoscience 1, 68–72 Andersson, P.S., Porcelli, D., Frank, M., Björk, G., Dahlqvist, R. and Gustafsson, Ö. (2008): Neodymium isotopes in seawater from the Barents Sea and Fram Strait Arctic- Atlantic gateways.- Geochim. Cosmochim. Acta 72, 2854-2867 Knies, J., J. Matthiessen, C. Vogt, J.S. Laberg, B.O. Hjelstuen, M.Smelror, E. Larsen, K. Andreassen, T. Eidvin and T.O. Vorren (2009): The Plio-Pleistocene glaciation of the Barents Sea–Svalbard region: a new model based on revised chronostratigraphy - Quaternary Science Reviews 28, 9-10, 812-829
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Analytical Chemistry, 83 (16). pp. 6395-6400.
    Publication Date: 2016-04-25
    Description: Titanium (Ti) is present as a trace element in seawater at extremely low concentrations (5-350 pM, where 1 pM = 10(-12) mol L(-1)) throughout the water column. Presently, little is known about the marine biogeochemistry of Ti and there is a distinct lack of oceanic measurements of Ti, because of the combined difficulties of trace-metal clean sampling for an element at such low levels and the lack of a suitable shipboard method of analysis. Here, a new cathodic stripping voltammetry procedure is presented for the rapid determination of Ti at pM concentrations in seawater that is capable of being used directly at sea. This method utilizes the catalytic enhancement of the reduction of the complex formed between Cupferron (N-nitrosophenylhydroxylamine) and Ti(IV). While Cupferron itself acts as both a complexing agent and an oxidizing agent, it was found that the optimal sensitivity was with bromate as an auxiliary oxidant. An advantage of this method is that it is useable over the pH range of 5.5-8. Under the conditions employed in this work, detection limits ranged from 5 pM to 12 pM. This new catalytic method is significantly more sensitive than existing methods and has been extensively tested at sea in the Atlantic and Southern Oceans.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Journal of the American Chemical Society, 133 (15). pp. 5913-5920.
    Publication Date: 2020-07-16
    Description: The conversion of alkylboranes to the corresponding alkanes is classically per-formed via protonolysis of alkylboranes. This simple reaction requires the use of severe reaction conditions, that is, treatment with a carboxylic acid at high temperature (〉150 °C). We report here a mild radical procedure for the transformation of organoboranes to alkanes. 4-tert-Butylcatechol, a well-established radical inhibitor and antioxidant, is acting as a source of hydrogen atoms. An efficient chain reaction is observed due to the exceptional reactivity of phenoxyl radicals toward alkylboranes. The reaction has been applied to a wide range of organoboron derivatives such as B-alkylcatecholboranes, trialkylboranes, pinacolboronates, and alkylboronic acids. Furthermore, the so far elusive rate constants for the hydrogen transfer between secondary alkyl radical and catechol derivatives have been experimentally determined. Interestingly, they are less than 1 order of magnitude slower than that of tin hydride at 80 °C, making catechols particularly attractive for a wide range of transformations involving C−C bond formation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Journal of Agricultural and Food Chemistry, 59 (13). pp. 6829-6836.
    Publication Date: 2020-07-27
    Description: Macroalgae have for centuries been consumed whole among the East Asian populations of China, Korea, and Japan. Due to the environment in which they grow, macroalgae produce unique and interesting biologically active compounds. Protein can account for up to 47% of the dry weight of macroalgae depending on species and time of cultivation and harvest. Peptides derived from marcoalgae are proven to have hypotensive effects in the human circulatory system. Hypertension is one of the major, yet controllable, risk factors in cardiovascular disease (CVD). CVD is the main cause of death in Europe, accounting for over 4.3 million deaths each year. In the United States it affects one in three individuals. Hypotensive peptides derived from marine and other sources have already been incorporated into functional foods such as beverages and soups. The purpose of this review is to highlight the potential of heart health peptides from macroalgae and to discuss the feasibility of expanding the variety of foods these peptides may be used in.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2023-11-08
    Description: EGU2011-12864 The Woodlark Basin east of Papua New Guinea represents one of the few places on Earth where a spreading axis propagates into continental crust. This special tectonic setting allows insights into the evolution of magma composition as continental extension and break-up changes to the formation of ocean crust. We report here geochemical results on samples collected in 2009 from the four segments closest to the continental breakup, from segment 1 which abuts the detachment fault responsible for continental extension on Moresby Seamount in the West, to segment 4, representing mature oceanic crust in the East. A total of 208 glass samples have been analyzed for their major (EMPA) and trace element (LA-ICPMS) compositions. The data show strong E-W variations. Samples ranging from tholeiitic basalt and basaltic andesite to andesite and rhyolite are found on Segment 1. They have generally high alkali values and a wide range of trace element contents and ratios. Segments 2 to 4 magmas in contrast only comprise tholeiitic basalt with lower alkali contents and a more restricted range of trace element chemistry. The geochemical differences between the segments cannot be attributed to differentiation processes alone, and different sources are required. High Ba/La, (La/Sm)N, Rb/Sr, and Th/La on Segment 1 suggest a derivation from an enriched mantle source, while low Nd/Pb and Nb/U suggest that some of the enrichment may also reflect the influence of continental crust during magma genesis. Whether this continental signature is present in the form of recycled material in the mantle or as rafted continental blocks in the axial region is at present unclear. In contrast to rocks from segment 1, trace element compositions of volcanic glasses from segments 2 to 4 show a stronger MORB signature, presumably reflecting more mature spreading in this part of the basin. The influence of continental material appears to be minimal, suggesting that uncontaminated asthenosphere quickly flows into the rift and/or that continental blocks are not retained in the axial region for long time periods following the rifting-spreading transition.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2021-03-29
    Description: This proceeding volume results from the submitted abstracts of the international symposium “The Stability of Rainforest Margins: Linking Ecological, Economic and Social Constraints” held on September 19 – 23, 2005 in Göttingen, Germany. Tropical rainforests disappear at an alarming rate causing unprecedented losses in biodiversity and ecosystem services. Rainforests are hot spots of biodiversity as well as important carbon sinks. Despite an increased recognition of the value of these and other valuable public goods provided by tropical rainforests at national and international levels, the rainforests of Asia, Africa, Australia and Latin America continue to be seriously threatened by various forms of human encroachment. The analysis of policies and socio-economic and ecological determinants that either stabilize or threaten tropical forest margins requires a holistic interdisciplinary scientific approach. Such an approach has been adopted by a large scale research program titled “Stability of Rainforest Margins in Indonesia” (www.storma.de). This research program started in 2000 and is jointly conducted by the two German Universities, the Georg-August-University of Göttingen (GAUG) and the University of Kassel (UNIK), and by two Indonesian Universities, the Agricultural University of Bogor (Institut Pertanian Bogor, IPB) and the Tadulako University (UNTAD) in Palu. Referring to the main research foci of STORMA, the symposium features three interconnected thematic foci of interdisciplinary research. They refer to changes in the extent and intensity of agricultural and forest land use in tropical forest margins and their implications for rural development and for conservation of natural resources such as biodiversity, soils and water. The first focus “Integrated spatial modeling of land use in tropical forest margins” concerns rain forest margins around the world which comprise a variety of landuse systems, with forest gardens, annual crops in slash-and-burn and agroforestry systems, as well as intensive cultivation, mostly in the valleys. An understanding of the dynamics of land-use change and related resource degradation under various policies scenarios is required, and strategies to reduce and potentially reverse degradation processes are to be developed. The second focus “Sustainable management of agroforestry systems” concerns lowintensity agroforestry which may support high biodiversity stabilizing ecosystem functioning, in particular when shaded by natural trees and neighboured by natural forest. In contrast, high-intensity agroforestry with planted shade trees and in an agricultural landscape context may be characterized by less environmental benefits and high agrochemical inputs. In this focus, the ecological and socio-economic benefits of different management practices will be compared and related to patterns and processes in natural forests. The third focus “Ecological and socio-economic impacts of different forest-use intensities” analyzes ecological and socio-economic benefits and costs across different types of forest use. The consequences of low- and medium-intensity forest-use practices, such as selective timber and rattan extraction, for biodiversity and ecosystem functioning are assessed. We are grateful to our sponsors, namely the German Research Council (DFG), the Georg-August-University Göttingen and the University of Kassel. Our special Thanks goes to the Universities Institut Pertanian Bogor (IPB) and Tadulako University (UNTAD) in Palu for their cooperation in the Collaborative Research Centre (SFB 552) “Stability of Rainforest Margins in Indonesia” (STORMA).
    Description: conference
    Keywords: 333.7 ; QEL 000 ; QG 380 ; UBA 700 ; UBO 600 ; VOI 210 ; QFC 210 ; QFC 200 ; QFC 450 ; QFC 445 ; human activity ; tropical environment ; rain forests ; land-use ; natural resources ; water balance ; pollution ; ecosystems ; biodiversity ; symposia ; meeting ; 38.09
    Language: English
    Type: anthology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    American Chemical Society
    In:  Industrial & Engineering Chemistry Research, 49 (11). pp. 5231-5245.
    Publication Date: 2020-07-29
    Description: Methane hydrate, a potential future energy resource, is known to occur naturally in vast quantities beneath the ocean floor and in permafrost regions. It is important to evaluate how much methane is recoverable from these hydrate reserves. This article introduces the theoretical background of HydrateResSim, the National Energy Technology Laboratory (NETL) methane production simulator for hydrate-containing reservoirs, originally developed for NETL by Lawrence Berkeley National Laboratory (LBNL). It describes the mathematical model that governs the dissociation of methane hydrate by depressurization or thermal stimulation of the system, including the transport of multiple temperature-dependent components in multiple phases through a porous medium. The model equations are obtained by incorporating the multiphase Darcy’s law for gas and liquid into both the mass component balances and the energy conservation equations. Two submodels in HydrateResSim for hydrate dissociation are also considered: a kinetic model and a pure thermodynamic model. Contrary to more traditional reservoir simulations, the set of model unknowns or primary variables in HydrateResSim changes throughout the simulation as a result of the formation or dissociation of ice and hydrate phases during the simulation. The primary variable switch method (PVSM) is used to effectively track these phase changes. The equations are solved by utilizing the implicit time finite-difference method on the grid system, which can properly describe phase appearance or disappearance as well as the boundary conditions. The Newton-Raphson method is used to solve the linear equations after discretization and setup of the Jacobian matrix. We report here the application of HydrateResSim to a three-component, four-phase flow system in order to predict the methane produced from a laboratory-scale reservoir. The first results of HydrateResSim code in a peer-reviewed publication are presented in this article. The numerical solution was verified against the state-of-the art simulator TOUGH+Hydrate. The model was then used to compare twodissociation theories: kinetic and pure equilibrium. Generally, the kinetic model revealed a lower dissociation rate than the equilibrium model. The hydrate dissociation patterns differed significantly when the thermal boundary condition was shifted from adiabatic to constant-temperature. The surface area factor was found to have an important effect on the rate of hydrate dissociation for the kinetic model. The deviation between the kinetic and equilibrium models was found to increase with decreasing surface area factor.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2010, 02.05.-07.05.2010, Vienna, Austria . Geophysical Research Abstracts .
    Publication Date: 2019-09-23
    Description: EGU2010-13373 The frequency of volcanic activity varies on a wide rangeof spatial and temporal scales, from 〈1 yr. periodicities in single volcanic systems to periodicities of 106 yrs. in global volcanism. The causes of these periodicities are poorly understood although the long-term global variations are likely linked to plate-tectonic processes. Here we present evidence for temporal changes in eruption frequencies at an intermediate time scale (104 yrs.) using the Pleistocene to recent records of widespread tephras of sub-Plinian to Plinian, and occasionally co-ignimbrite origin, along the Pacific Ring of Fire, which accounts for about half of the global length of 44,000 km of active subduction. Eruptions at arc volcanoes tend to be highly explosive and the well-preserved tephra records from the ocean floor can be assumed to be representative of how eruption frequencies varied with time. Volcanic activity along the Pacific Ring of Fire evolved through alternating phases of high and low frequency; although there is modulation by local and regional geologic conditions, these variations have a statistically significant periodicity of 43 ka that overlaps with the temporal variation in the obliquity of the Earth’s rotation axis, an orbital parameter that also exerts a strong control on global climate changes. This may suggest that the frequency of volcanic activity is controlled by effects of global climate changes. However, the strongest physical effects of climate change occur at 100 ka periods which are not seen in the volcanic record. We therefore propose that the frequency of volcanic activity is directly influenced by minute changes in the tidal forces induced by the varying obliquity resulting in long-period gravitational disturbances acting on the upper mantle.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2010, 02.05.-07.05.2010, Vienna, Austria . Geophysical Research Abstracts .
    Publication Date: 2012-07-06
    Description: EGU2010-10518 Seafloor compliance is the transfer function between pressure and vertical displacement at the seafloor Infragravity waves in the oceanic layer have long periods in the range of 30 – 500 s and obey a simple frequencywavenumber relation. Seafloor compliance from infragravity waves can be analyzed with single station recordings to determinate sub-seafloor shear wave velocities. Previous studies in the Pacific Ocean have demonstrated that reliable near-surface shear wave profiles can be derived from infragravity wave compliance. However, these studies indicate that, beside the water depth the compliance measurements are limited by instrument sensitivity, calibration uncertainties and possibly other effects. In this work seafloor compliance and infragravity waves are observed at two different locations in the Atlantic Ocean: the Logatchev hydrothermal field at the Mid Atlantic Ridge and the Azores (Sao Miguel Island). The data was acquired with the broadband ocean compliance station developed at the University of Hamburg as well as ocean station from the German instrument pool for amphibian seismology (DEPAS) equipped with broadband seismometers and pressure sensors. Vertical velocity and pressure data were used to calculate power spectral densities and normalized compliance along two profiles (one in each location). Power spectral densities show a dominant peak at low frequencies (0.01-0.035Hz) limited by the expected cut-off frequency, which is dependent on the water depth at each station. The peak has been interpreted as a strong infragravity wave with values between 10-14 and 10-11 (m/s2)2/Hz and 104 and 106 (Pa2)2/Hz for acceleration and pressure respectively. The results show compliance values between 10-10 and 10-8 1/Pa and its estimations take into account the coherence between seismic and pressure signals in order to confirm that the seismic signals in the infragravity waves are caused by pressure sources. Shear wave velocity models, with depth resolution from 200 to 2500 m for the deep water stations, were derived from compliance. Preliminary results indicate shear wave velocity increasing from 200 to 3500 m/s.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2010, 02.05.-07.05.2010, Vienna, Austria . Geophysical Research Abstracts .
    Publication Date: 2012-07-06
    Description: EGU2010-9841 Active mud volcanoes, where changing salinities of pore fluids, large temperature gradients and occurrences of free gas are frequently observed, should potentially exhibit significant variability in their internal resistivity structure. This is due to the fact that the bulk resistivity is mainly determined by the porosity of sediments and the electrical resistivity of the pore filling contained therein. The resistivity variations may be derived from controlled source electromagnetic (CSEM) measurements. CSEM systems consist of an electric dipole transmitter producing a time varying source field and electric dipole receivers, which measure the earth´s response to this signal. For a RWE Dea funded investigation of fluid and gas leakages at the North Alex Mud Volcano (NAMV) - a comparatively small target with an area of about 1km2 - we have developed a new high resolution CSEM system. The system consists of several autonomous electric dipole receivers and a lightweight electric dipole transmitter, which can be mounted on a small remotely operated underwater vehicle (ROV). The use of a ROV allows for a precise placement of the transmitter, which is a necessary prerequisite for the investigation of such a small target. Furthermore, electromagnetic signals may be transmitted from different directions with respect to the stationary receivers, allowing for a 3D-style tomographic experiment. In this experiment, ten receivers were deployed over the surface of NAMV at a total of 16 receiver locations. During three successful dives with a Cherokee ROV (Ghent University, Belgium), the transmitter was deployed at a total of 80 locations. Here we present first quantitative results consisting of apparent resistivity estimations from the CSEM time domain data for each transmitter-receiver pair. The apparent resistivity map shows that the NAMV indeed has a heterogeneous resistivity structure with apparent resistivities varying by at least a factor of two: low apparent resistivities (~ 0.8Ωm) are found towards the center of the MV, whereas higher apparent resistivities (~ 1.6Ωm) prevail away from the center. In a second step, we interpret the time-domain data based on 1D inversions. Good data fits can be achieved by models containing 2-3 layers. Generally, the models indicate low resistivities at the surface, which can be associated with penetrating salt water and/or high temperatures. Toward greater depths, increasing resistivities presumably are due to a combination of compaction of sediments (i.e. reduced pore space), an increased presence of fresh water and possible occurrences of free gas. For some 1D models, the increase in resistivity exceeds a factor of 10 or more and layer interfaces are indicated down to depths of up to 70m. The derived resistivity variations observed at the NAMV will be interpreted in conjunction with temperature (Feseker, this session), fluid flow (Brückmann et al., this session) and seismic data (Bialas et al., this session) acquired. Temperature variations measured in the upper few meters are related to fluid flow, where high temperatures are indicative of upwelling fluids of low salinity and low temperature of either a downward flow of saline fluids or no flow activity. This type of surface measurement constitutes an integrative fluid flow gauge, which we can resolve vertically with our resistivity models. Seismic data yield a background structure to our resistivity model. New analysis of seismic data shows that seismic activity may also be linked to fluid flow activity, which we aim to match with resistivity variations and oscillations, which were observed in the electric and magnetic fields (Lefeldt et al., this session).
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    facet.materialart.
    Unknown
    Copernicus
    In:  [Talk] In: EGU General Assembly 2010, 02.05.-07.05.2010, Vienna, Austria . Geophysical Research Abstracts ; EGU2010-5184 .
    Publication Date: 2012-07-06
    Description: Recently Hathorne et al. (2009) documented large intratest trace element (TE) variations in planktonic foraminifera from a single sediment trap sample that could not be explained by variations in water column properties. The laser ablation ICP-MS depth profiles of trace elements through the test walls revealed strong positive correlations between Li, Mg, Mn and Ba resulting from the mixing of a lower TE outer calcite with a higher TE inner calcite. In contrast Sr/Ca ratios remained relatively constant throughout the test wall. These intratest TE variations likely result from biomineralization processes and therefore should be explained by any valid biomineralization model. However, changes in calcite precipitation rate, crystal structure, or the chemical composition of the internal calcification reservoir could not, by themselves, fully account for the pattern of cation intratest variability. Here I expand on this work and investigate if a model of coral biomineralization by Sinclair and Risk (2006) can be adapted to explain the pattern of intratest TE variability in foraminifera. It is clear that the low Mg calcite secreting foraminifera must reduce the Mg/Ca ratio of the calcifying solution by at least a factor of 10 (e.g. Hathorne et al., 2009) and it has been suggested this is achieved by active removal of Mg from the calcification reservoir, although the actual mechanisms remain debatable (e.g. Bentov and Erez, 2006). However, a recent study of the calcification of a low Mg calcite species in the laboratory found a large shortcoming in the amount of Ca potentially provided by seawater transported to the site of calcification in vacuoles compared to a conservative estimate of the amount required to form the new calcite wall (de Nooijer et al., 2009a). This suggests active Ca transport to the site of calcification is required to provide sufficient Ca. If Ca specific, this Ca addition would effectively dilute the TE content (including Mg) of the calcification reservoir to varying degrees and potentially cause the positive TE correlations seen across the test wall. Sinclair and Risk (2006) used this dilution model to successfully explain some TE correlations in coral skeletons. This model can be effectively adapted to foraminifera as it accounts for recent observations of foraminiferal calcification including the transport of seawater by liquid endocytosis to the calcification site and an elevated pH at the site of calcification (Bentov et al., 2009; de Nooijer et al., 2009a, 2009b). This model therefore provides a powerful tool with which to integrate constraints from experimental observation with those from micro-analytical measurements to improve the accuracy, precision and scale of the palaepalaeoceanographic application of foraminiferal geochemistry. Bentov and Erez (2006) Geochem. Geophys. Gepsyst. 7, Q01P08. Bentov et al. (2009) PNAS 106, 21500. de Nooijer et al. (2009a) Biogeosciences 6, 2669. de Nooijer et al. (2009b) PNAS 106, 15374. Hathorne et al. (2009) Paleoceanography 24, PA4204. Sinclair and Risk (2006) Geochim. Cosmochim. Acta 70, 3855.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    facet.materialart.
    Unknown
    Copernicus
    In:  [Poster] In: EGU General Assembly 2010, 02.05.-07.05.2010, Vienna, Austria . Geophysical Research Abstracts ; /EGU2010-12153 .
    Publication Date: 2012-07-06
    Description: We present Mg/Ca analyses performed via a Flow Through sequential dissolution device connected to an ICP-OES on the planktonic foraminifer Globorotalia inflata. The aim of the study is to explore the possibility to reconstruct the thermal gradient in the water column by separating non-crusted and crusted calcite phases in the tests of G. inflata using the difference between their Mg/Ca ratios as a measure of the thermal gradient. An important assumption is that the non-crusted part of the tests is calcified in shallow, warmer water than the crusted part. For analyses a range of different preparation steps were used to determine the ideal way of separating the phases. Foraminifer tests were (not) cleaned, (not) crushed, and (not) pulverized before online analysis with the FT device. To analyze samples with a FT device the foraminifer tests are placed on a filter with a mesh of 0.45 μm preventing clay minerals to wash through. A sequential dissolution protocol first rinses the samples with buffered Seralpur water before QD HNO3 is added in small steps to create a ramp of increasing acid strength. As acid is kept constant at each concentration for several minutes, dissolution of a specific calcite phase can take place. Initial results show that it is most effective to slightly crush the tests without applying standard cleaning procedures, but rather analyze them without cleaning. Samples were selected from the South Atlantic (core tops and specific downcore samples) and the Mediteterranean (plankton tows). All samples were chosen based on previous work on them to provide comparison with routinely analysed Mg/Ca ratios. The South Atlantic samples have been analyzed extensively as bulk samples separated in difference size fractions and crusted vs. non-crusted (Groeneveld and Chiessi). The Mediterranean samples were not only analyzed as bulk samples but also by Laser Ablation ICP-MS (von Raden et al.). Results show that bulk analyses are reliably reproduced by the FT method, especially for samples which are dominated by crusted calcite. Samples which were uncrusted often gave much higher Mg/Ca ratios than the bulk analyses. These higher Mg/Ca ratios mainly occur in the plankton tow samples and were also identified with Laser Ablation ICP-MS. A possible reason for this could be the presence of a high Mg amorphous calcite layer on the outside of foraminifer tests which have not completed their calcification yet as was recently also pointed out in several other studies. Identification of the crusted and uncrusted phases, and therewith a thermal gradient, seems to give the expected differences but a more rigorous statistical treatment is needed to pinpoint singular dissolution phases.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2012-07-06
    Description: EGU2010-2934 The exploration of the arctic seas require an integrated approach applying different infrastructures. In Fall 2009 German and Russian scientists performed a geo marine cruise off Kamchatka and in the western Bering Sea within the frame of the KALMAR-Project. Two main research subjects formed the scientific backbone of the cruise: The first objective focuses on the geodynamic and volcanological magmatic development of the Kuril-Kamchatka island arc system and the Kamchatka Aleutean Islands Triple-Junction. Very little is known about the composition of the mantle and the oceanic crust as well as of the seamounts including their ages. The best studied site is the Volcanologist’s Massif located between the Bering- and the Alpha Fracture Zone (Tsvetkov 1990, Volynets et al. 1992, Yogodzinsky et al. 1994), which structurally belongs to the Komandorsky Basin. The oldest rocks of the Volcanologist´s Massif show very similar trace element and isotope signatures like those rocks cropping out in the volcanoes on Kamchatka in the prolongation of the Alpha Fracture Zone (Portnyagin et al. 2005a), indicating similar conditions of magma formation. The top of the Volcanologist´s Massif is characterized by the young (〈 0.5 Ma) and hydrothermally active Piip volcano, which consists of special magnesium rich andesites ("Piip type"). Another hot site was the Meiji-Seamount which is the northernmost Seamount of the hotspot spur of the Hawaii-Emperor-Seamount chain, having an age of probably 〉 85 Ma. The only existing basement rocks from this seamount were gained during DSDP Leg 19. These are basalts with MORB like trace element and isotope signatures (Keller et al. 2000, Regelous et al. 2003). These data indicate that the Hawaii-Hotspot was at a MOR in Cretaceous time and that large volumes of depleted mantle material played a´role during the magma formation. The second objective focuses on paleo-oceanographic investigations concentrating on the sediments along the eastern continental slope of Kamchatka, in the Komandorsky Basin, and on the Shirshov Ridge in order to explore paleoclimate archives to better understand the subpolar water mass transfer and the oceanographic and climatic development in the subarctic NW-Pacific. Comparisons of Late Pleistocene and Holocene temperature changes within the near surface water masses between the NW-Pacific and the N-Atlantic resulted in a new hypothesis, the "Atlantic-Pacific seesaw" (Kiefer et al. 2001, Kim et al. 2004, Kiefer and Kienast, 2005). This Atlantic-Pacific pattern of opposite temperature variations dominates the last 60ka on millennial timescales. Modelling results of Saenko et al. (2004) support the hypothesis of the "Atlantic-Pacific seesaw" and they postulate a mechanistic connection between the two regions driven by salinity variations, which couples both regions through the thermohaline circulation. A different model relates the Holocene Atlantic-Pacific dipole to the atmospheric tele-connection between the Arctic Oscillation/N-Atlantic Oscillation and the Pacific N-American Oscillation (Kim et al. 2004). http://kalmar.ifm-geomar.de
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2020-07-21
    Description: The chemical composition of the Caribbean sponge Pandaros acanthifolium was reinvestigated and led to the isolation of 12 new steroidal glycosides, namely, pandarosides E-J (1-6) and their methyl esters (7-12). Their structures were determined on the basis of extensive spectroscopic analyses, including two-dimensional NMR and HRESIMS data. Like the previously isolated pandarosides A-D (13-16), the new compounds 1-12 share an unusual oxidized D-ring and a cis C/D ring junction. The absolute configurations of the aglycones were assigned by interpretation of CD spectra, whereas the absolute configurations of the monosaccharide units were determined by chiral GC analyses of the acid methanolysates. The majority of the metabolites showed in vitro activity against three or four parasitic protozoa. Particularly active were the compounds 3 (pandaroside G) and its methyl ester (9), which potently inhibited the growth of Trypanosoma brucei rhodesiense (IC(50) values 0.78 and 0.038 mu M, respectively) and Leishmania donovani (IC(50)'s 1.3 and 0.051 mu M, respectively).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2021-03-29
    Description: Die Västervik Region liegt an einer Haupt-Terran-Grenze im Baltischen Schild. Im NE schließen sich die Einheiten des Südsvecofennischen Vulkanitgürtels mit Altern 〉1,85Ga an, im SW folgen die Granitoide des Transskandinavischen Magmatitgürtles (TMZ) mit Altern 〈1,85Ga. Die Metasedimente der Västervik Formation bilden die stratigraphisch älteste Einheit der Västervik Region. Ihre Stellung in Bezug auf die svecofennischen Metasedimente des Bothnischen Beckens ist noch unklar. Sie können nach ihren mineralogischen Paragenesen in vier Gruppen klassifiziert werden: reine Quarzite, glimmerführende Quarzite, Glimmerquarzite und quarzitische Gneise. Vermutlich zeitgleich mit der Intrusion der großvolumigen Granitoidmagmen ab 1.85 Ga wurde die Västervik Formation amphibolitfaziell überprägt. Dies führte innerhalb der Metasedimente zur Bildung von Cordierit, Sillimanit und Andalusit sowie akzessorischem Granat. Der Beginn der Sedimentation ist begrenzt durch das Vorkommen detritischer Zirkone mit Altern ab 1.87Ga. Etwa 75% der gemessenen detritische Zirkone zeigt eine Altersgruppierung von 1,8 bis 2,1 Ga, die restlichen 25% zeigen archaische U/Pb-Alter von 2,8 bis 3,0 Ga (Claesson et al. 1993, Sultan et al. 2005). Die Nd-Isotopensignaturen der Proben zeigen eine sehr homogene Mischung und Schüttung der Sedimente mit subparallelem Verlauf der Nd- Entwicklungslinien und einem sehr engen TDM (Nd) Altersspektrum von 2,2 bis 2,4Ga. Diese Ergebnisse deuten auf ein konstantes Mischungsverhältnis von proterozoischen und archaischen Anteilen hin...
    Description: conference
    Keywords: 551 ; VBO 000 ; VBN 500 ; VKB 292 ; VKB 250 ; VJJ 110 ; VJB 312 ; VED 200 ; VEG 110 ; Isotopengeologie ; Geochronologie einzelner Regionen im allgemeinen ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Metasedimente {Petrologie} ; Geochemie der Stabilen Isotopen ; Geochemie der Metamorphite ; Schweden {Geologie} ; Europäische Plattform {Geologie} ; Svekofenniden ; Västervik 〈Region〉 ; Proterozoikum ; Metasediment ; Samarium ; Neodym ; Isotopengeochemie
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2021-03-29
    Description: The synformal geometry of the 1.85Ga Sudbury Igneous Complex (SIC), an impact melt sheet resulting from largemagnitude meteorite impact, attests to post-impact deformation. However, in contrast to the overlying Onaping Formation, a heterolithic impact melt breccia, the SIC shows little evidence for pervasive ductile strain. This pertains in particular to its NE-lobe characterized by a curvature of about 100° in plain view. This curvature has been interpreted either as a fold or as a primary feature. In order to test these scenarios, a detailed structural analysis was conducted in the core of the NE-lobe, which consists of rocks of the Onaping Formation...
    Description: conference
    Keywords: 551 ; VKB 280 ; VKB 295 ; VAE 140 ; VEV 127 ; VKA 200 ; Impaktgesteine {Petrologie} ; Metamorphe Komplexe, Nordamerika {Petrologie} ; Gesteinsdeformation {Strukturgeologie} ; Ontario {Geologie} ; Gefügekunde der Gesteine ; Sudbury 〈Ontario. Region〉 ; Mehrfachringbassin ; Proterozoikum ; Impaktmetamorphes Gestein ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2021-03-29
    Description: Seit dem Mesozoikum wächst die kontinentale Kruste am aktiven Plattenrand von Kamtschatka durch Akkretion allochthoner Terrane. Dieses Wachstum manifestiert sich in der differenziellen Exhumierung und Hebung tektonischer Blöcke innerhalb des Akkretionskeils, parallel zum Kamtschatka- Graben. Die Kinematik der Exhumierung soll mittels strukturgeologischer und neotektonischer Deformationsanalyse erfasst und mit thermochronologischen Untersuchungen an Apatiten bis etwa ins Untere Pliozän quantifiziert werden.
    Description: conference
    Keywords: 551 ; VAE 880 ; VAE 400 ; VBN 500 ; VEG 190 ; Passive und aktive Kontinentalränder {Geologie} ; Tektogenese {Geologie} ; Geochronologie einzelner Regionen im allgemeinen ; Koriakia-Kamtchatkasystem {Geologie} ; Kamtschatka 〈Oblast〉 ; Kontinentalrand ; Deformation 〈Geologie〉 ; Hebung 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2021-03-29
    Description: Die Grenze zwischen zwei ophiolithischen Decken der penninischen Alpen, der Zermatt-Saas-Zone (unten) und der Combinzone (oben), markiert zugleich einen bedeutenden Sprung der bei der tertiären alpinen Metamorphose maximal erreichten Drücke. Während die Zermatt-Saas-Zone Ultrahochdruckmetamorphose (25–30 kbar/550–600°C, Bucher et al. 2005) erfuhr, erreichte die Combinzone lediglich blauschieferfazielle Bedingungen (13–18 kbar/380– 550°C, Bousquet et al. 2004). Vor allem die Polarität des Drucksprunges führte dazu, daß die Deckengrenze zumeist als gewaltige südostvergente Abschiebung interpretiert wurde (z.B. Ballèvre & Merle 1993, Reddy et al. 1999). Strukturgeologische Geländebeobachtungen ergeben jedoch sowohl für das Hangende als auch das Liegende der Combinstörung die folgende kinematische Entwicklung: i) Nordwestvergente, überschiebende Scherung (D1), ii) (Süd)westvergente Scherung (D2),iii) Südostvergente, abschiebende Scherung (D3). Alle drei Deformationsphasen fanden in beiden Einheiten unter grünschieferfaziellen Bedingungen statt... Die Rekonstruktion ergibt, daß die Combinstörung hauptsächlich als Überschiebung aktiv war. Die Exhumierung der Gesteinseinheiten im Liegenden wurde nicht durch Extension, sondern durch vertikale Ausdünnung der Kruste während horizontaler Kontraktion bewirkt.
    Description: conference
    Keywords: 551 ; VAE 811 ; VAE 400 ; VEB 168 ; VAE 140 ; Alpidische Orogene {Geologie} ; Tektogenese {Geologie} ; Schweizer Alpen {Geologie} ; Gesteinsdeformation {Strukturgeologie} ; Penninikum ; Tektonische Decke ; Scherzone ; Deformation 〈Geologie〉 ; Hebung 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Analytical modelling of geological fractures is now at an exciting stage. In view of the ever-mounting amount of fracture data available, and the need for a European overview of the state of the art, we correlate fractures from across the continent. In order to achieve relevant and meaningful statistics, the dataset of millions of entries was downsampled to filter out inadequate and irrelevant values. The resulting data are the object of this study...
    Description: conference
    Keywords: 551 ; VEA 000 ; VAE 150 ; VAE 830 ; Europa insgesamt {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Bruchschollenstrukturen {Geologie} ; Europa ; Bruchtektonik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2021-03-29
    Description: Piton de la Fournaise (Réunion Island) is an active basaltic shield volcano in the south-western part of the Indian Ocean. The activity consists essentially of lava being issued from two rift zones close to the summit cone. The summit cone has been monitored since 1980 by the OVPF (Volcanological Observatory of Piton de la Fournaise). Geodetic data and radar interferometry show a systematic asymmetric pattern of deformation associated with all the N–S trending eruptive fissures (Briole et al. 1998, Sigmundsson et al. 1999). The asymmetric deformation has been interpreted in various ways. The two main models proposed are (1) eastward dip of the dykes, based on inversion of data provided by radar interferometry (Sigmundsson et al 1999), and (2) the existence of a free boundary in the east part of the volcano. The second model allows the accommodation of dykes by eastward displacements, whilst the western part of the volcano is supported by the existing Piton des Neiges (Lénat et al., 1989). However,no displacements occur along the eastern coastline of Piton de la Fournaise. The only parts of the volcano affected by deformation are the rift zones and the summit cone. Moreover, geodetic data provided by the new real-time GPS network show that there is an asymmetric deformation of the summit cone prior to eruption (Staudacher 2005). The deformation itself seems to be related to pressure increase in the magma chamber. Absence of permanent displacements during periods of rest (such as 1992–1998) (Briole et al. 1998) support this link between magmatic pressure and deformation. Here we complement previous deformation studies by the results of several numerical models that aim at understanding the internal processes resulting in deformation of the volcano...
    Description: conference
    Keywords: 551 ; VAD 700 ; VAD 300 ; VAE 200 ; VEZ 200 ; Regionaler Vulkanismus {Geologie} ; Vulkanformen und Vulkantypen {Geologie} ; Geodynamik der Lithosphäre {Geologie} ; Indischer Ozean {Geologie} ; Piton de la Fournaise ; Schildvulkan ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2021-03-29
    Description: Impact of solid bodies is the most fundamental of all processes that have taken place on the terrestrial planets in our Solar system (Shoemaker 1977). On Earth, impact cratering was the dominant geologic process during the period of the early heavy bombardment until 3.8Ga. A constant asteroid impact flux exists since that time. Although deformation of the crust by meteorite impacts is now subordinate with respect to tectonics, it represents an important, but often underestimated fraction of the bulk crustal deformation. Short-term deformation during hypervelocity impact events differs in many respects from standard tectonics: Unique conditions exist at pressures above the so-called Hugoniot elastic limit (HEL) of a particular mineral or rock. This state of compression is reached in a shock wave that propagates from the point of impact. Shock waves travel at supersonic velocity, heat and irreversibly deform the rock, and cause a residual motion of the material they have passed, which ultimately leads to the formation of parabolically shaped crater cavity of much larger extent than the projectile diameter. At pressure above the HEL minerals are subjected to shock metamorphism...
    Description: conference
    Keywords: 551 ; VKB 280 ; Impaktgesteine {Petrologie} ; Sandstein ; Impaktmetamorphose
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2021-03-29
    Description: Microscopic study is an indispensable step in the determination of the petrographic characteristics of rocks. In Cameroon just like in most developing countries, simple polarizing microscopes of the 20th Century constitute the only available material for macroscopic studies. A major difficulty encountered in the use of these instruments resides in the realisation of photographs of the different parts of the thin section that require illustrations. The technique that has been used upto now has been inefficient and unsatisfactory. Faced with this recurrent situation, we thought of setting up a new, semi-modern, practical and very economical technique for photographing the thin section.
    Description: conference
    Keywords: 551 ; VAE 120 ; VGB 400 ; VKA 130 ; Methodik {Strukturgeologie} ; Optische Bestimmungsmethoden {Mineralogie} ; Optische Petrographie ; Dünnschliffmikroskopie ; Mikrofotographie
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2021-03-29
    Description: Intense seismicity and intensely developed active and ancient fault systems are common to the Aegean Region. Extending/ thinning crust involves a complex interplay of (1) Gulf of Corinth riftexpansion, (2) west- and south-ward retreat of the Hellenic Trench, (3) westward impingement of the Anatolian Platen, and/or (4) propagation of the Anatolian Fault system into the Aegean. New geological/structural investigations on Kea (also known as Tzia), in the Western Cyclades reveal a low angle crustal-scale, detachment-type ductile shear zone probably formed during Miocene extension and thinning of the continental crust...
    Description: conference
    Keywords: 551 ; VEF 300 ; VAE 130 ; VKB 270 ; VAE 400 ; Griechenland und griechische Inseln {Geologie} ; Geomechanik ; Produkte mechanischer Deformation {Petrologie} ; Tektogenese {Geologie} ; Kea ; Erdkruste ; Extension 〈Geologie〉 ; Scherzone
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Gruppen von parallel einfallenden Abschiebungen treten in der Natur sehr häufig und in unterschiedlichsten Dimensionen auf. Existierende, überwiegend experimentelle Arbeiten führen einheitliches Einfallen auf laterale Festigkeitsschwankungen oder, vor allem, auf horizontale Scherspannungen zurück (e.g. Brun et al. 1994, Behn et al. 2002). Einheitliche horizontale Scherspannungen im großen Maßstab werden mit einer konsistenten Fließrichtung in der mittleren und/oder unteren Kruste erklärt. Beobachtungen in einigen der bedeutensten Rift-Systeme lassen jedoch beide Erklärungen als zentrale Ursache unwahrscheinlich erscheinen. In der Basin-and-Range-Provinz in den westlichen Vereinigten Staaten ändert sich die Einfallrichtung von parallelen Abschiebungen im Streichen der Störungen, so dass strukturelle Domänen mit intern einheitlicher Einfallrichtung entstehen, die von Blattverschiebungen untereinander getrennt werden. Eine solche Geometrie ließe sich nur mit bizarren Fließmustern in der Unterkruste erklären. Wir präsentieren numerische Extensionsexperimente von sprödem Material, das auf einem linear-viskosen Substrat ruht... In unseren Modell sind parallele Abschiebungen nicht, wie bisher angenommen, auf einheitlichen horizontalen Scherstress, sondern auf vertikale Normalspannungen zurückzuführen, d.h. auf den Widerstand, den das viskose Substrat vertikalen Blockbewegungen in der spröden Lage entgegensetzt. Wenn unser Modell richtig ist, würde das für Gebiete wie die Basin-and- Range-Provinz bedeuten, dass die spröde Oberkruste auf einer wenige Kilometer dicken, viskosen mittleren Kruste liegt, die wiederum ein festeres Substrat hat. Die Unterkruste müsste deutlich fester sein als die mittlere Kruste. Es scheint, dass Folgen von parallelen Abschiebungen häufig in dünnen, niedrig viskosen Lagen (etwa Ton oder Salz) wurzeln.
    Description: conference
    Keywords: 551 ; VAE 830 ; VAE 130 ; VAE 120 ; VBE 000 ; Bruchschollenstrukturen {Geologie} ; Geomechanik ; Methodik {Strukturgeologie} ; Modellierung von Prozessen in der Geosphäre ; Bruchscholle ; Abschiebung 〈Geologie〉 ; Geomechanik ; Numerisches Modell
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2021-03-29
    Description: There is substantial need in mineral exploration to understand the structural controls on ore deposition for these types of deposits in order to predict the localities of new ones. Application of basic principles of rock mechanics, and numerical simulations of deformation and fluid flow processes provide fundamental insights to Proterozoic hydrothermal mineralization atMount Isa, Australia. The rheology of layered meta-sedimentary rocks, and the orientation and position of these layered rocks relative to major fault systems were the key controls on ore deposition...
    Description: conference
    Keywords: 551 ; VQB 000 ; VQD 200 ; VRA 300 ; VTS 400 ; VQC 000 ; Tektonik von Lagerstätten ; Metamorphe Lagerstätten ; Buntmetalle {Lagerstättenkunde} ; Queensland {Rohstoffgeologie} ; Lagerstättengenese ; Mount-Isa-Gebiet ; Hydrothermale Erzlagerstätte ; Geodynamik ; Metallogenese
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2021-03-29
    Description: Most asteroids strike their target at an oblique angle (Pierazzo & Melosh 2000). The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and morphological, structural, geophysical as well as depositional criteria were used to infer an oblique impact (e.g. for Chicxulub, Schultz & D’Hondt 1996, Ries- Steinheim, Stöffler et al. 2003, Mjölnir & Tsikalas 2005). However, the significance of such criteria in predicting impact angle or direction is a matter of debate (c.f. Schultz & Anderson, 1996, Ekholm & Melosh 2001). Particularly, it is not yet known whether there is an influence of the impact angle on the displacement field during the collapse of large transient cavities, and thus, the final crater. For most impact angles, the shape of the final crater is controlled by its size. At a critical diameter (ca. 2–5 km on Earth), simple bowl shaped craters are getting gravitationally unstable and collapse to form complex craters, with a flat floor and a terraced rim (Melosh 1989). During collapse, the crater floor rises to form a central uplift, that may or may not be visible as a central peak, or, when the peak in turn collapses, as a peak ring at yet larger diameters.
    Description: conference
    Keywords: 551 ; VAE 150 ; VAX 000 ; VEV 277 ; Strukturelle Erscheinungen {Strukturgeologie} ; Akkretion extraterrestrischen Materials {Geologie} ; Utah {Geologie} ; Utah 〈Südost〉 ; Impaktstruktur ; Strukturgeologie
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2021-03-29
    Description: The 1.85 Ga Sudbury Igneous Complex (SIC) in central Ontario is now widely considered to be the erosional remnant of a deformed paleo-horizontal impact melt sheet, about 2.5 km in thickness. Deformed impact melt breccias of the Onaping Formation and postimpact metasedimentary rocks overlie the layered SIC, which in turn rests on shocked Archean basement and Paleoproterozoic cover rocks. The main mass of the Igneous Complex is subdivided from top to bottom into granophyre, quartz-gabbro and norite layers. Previous workers considered noncylindrical folding and NW-directed reverse faulting as the main structural processes that formed the asymmetric, syn-formal geometry of the SIC apparent in map view and seismic section. Structural studies support this model in the southern part of the impact structure, where greenschist-facies metamorphic tectonites of the South Range Shear Zone (SRSZ) accomplished structural uplift of the southern SIC by NW-directed reverse shearing. However, little evidence for pervasive ductile strain has been reported from the weakly metamorphosed eastern part of the SIC, the East Range, which is characterised by steep basal dips and maximal curvature in plan view. The objective of this study is to assess the structural inventory of the East Range in terms of post-emplacement deformation mechanisms. Our interpretation is based on published and newly acquired structural data. Planar mineral shape fabrics of cumulate plagioclase and pyroxene are developed in the intermediate quartz-gabbro and lower norite layers of the southern East Range SIC. Microstructures show little intracrystalline deformation in quartz. Euhedral cumulate plagioclase retains an angular outline indicating magmatic mineral fabric development. This magmatic foliation is concordant to SIC contacts or large-scale discontinuities in their vicinity (Fig. 1). Magmatic fabrics are observed rarely in the northern portion of the East Range. Here, tectonic foliations and S–C fabrics are developed sporadically at, and concordant to, brittle structures striking N–S. A weak tectonic foliation defined by chlorite that replaces magmatic minerals is developed in the upper granophyric SIC of the NE-lobe that connects the SIC’s North and East Ranges via a 105° arc. This foliation grades into a shape-preferred orientation of primary, i.e., magmatic, mafic minerals observed in the lower granophyre and underlying layers of the SIC. Mineral fabrics observed in the NE-lobe SIC are concordant to metamorphic foliations developed in the overlying Onaping Formation breccias. Both foliations strike parallel to the NE-Lobe’s acute bisectrix and, thus, display an axial-planar geometry typical for fabrics formed in the core of a buckle fold (Fig. 1). Brittle structures including centimetre-scale shear-fractures to kilometre-scale faultzones are observed in the eastern SIC and its host rocks. Largescale faults striking N–S cut the NElobe’s eastern limb causing variable magnitudes of strike separation of SIC contacts. Centimetre- to metrescale, brittle faults and chlorite-filled brittle-ductile shear-zones occur pervasively in the eastern SIC, often causing centimetre-scale offset of markers. Microstructures from first-order fault-zones indicate deformation at, and below, greenschist-facies metamorphic conditions. The concordance of magmatic and tectonic mineral shape fabrics in the NElobe indicates progressive deformation of the SIC during cooling from the magmatic state to lower greenschistfacies metamorphic conditions. Synmagmatic deformation of the SIC suggests that it was emplaced during ongoing orogenic deformation. Furthermore, maximum principal stress directions inferred from inversion of faultslip data collected in the Onaping Formation are orthogonal to metamorphic foliation surfaces at the same localities. This points to a similar deformation regime in the Onaping Formation during ductile and brittle deformation. The concordance of magmatic, metamorphic and brittle fabrics is explained best by a single progressive deformation event that was active while the SIC cooled and solidified. The lack of pervasive ductile deformation fabrics in the East Range SIC can be explained by rapid cooling of the impact melt sheet (within 100–500 ka) with respect to natural tectonic strain rates. While the geometry of mineral fabrics in the study area is compatible with large-scale, non-cylindrical folding, the low levels of ductile deformation suggest that shape-change of the eastern SIC has been accomplished mainly by discontinuous deformation. This deformation mechanism may have accomplished bulk NW-SE shortening that was accommodated by reverse shearing within the SRSZ, resulting in large strike separations of SIC contacts observed in the western part of the impact structure. By contrast, the eastern SIC may have accomplished such shortening by brittleductile, non-cylindrical folding at the eastern terminus of the SRSZ. The complex post-impact deformation pattern of the central Sudbury Structure results from impact into an active orogen.
    Description: conference
    Keywords: 551 ; VEV 127 ; VAE 150 ; VKB 280 ; VAE 400 ; Ontario {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Impaktgesteine {Petrologie} ; Tektogenese {Geologie} ; Sudbury 〈Ontario, Region〉 ; Mehrfachringbassin ; Tiefengestein ; Impaktmetamorphes Gestein ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2021-03-29
    Description: The anisotropy of magnetic susceptibility (AMS) can serve as a good indicator of strain in deformed carbonate rocks with diamagnetic susceptibility (Owens and Rutter 1978; de Wall 2000). However, the magnetic fabric due to the diamagnetic carbonate minerals is usually very weak and interpretation of the AMS in these rocks is often complicated by the presence of paramagnetic and ferromagnetic phases which overprint the diamagnetic subfabric. For this reason contributions from ferromagnetic and paramagnetic minerals to the AMS should be separated for a reliable interpretation of the AMS. Ferromagnetic contributions to the AMS can be separated by high-field measurements, using a torque magnetometer (Martin- Hernandez and Hirt 2001). The remaining paramagnetic and diamagnetic contributions can be discriminated by their different temperature dependencies. The paramagnetic susceptibility increases as an inverse function of temperature, whereas the diamagnetic part remains constant. Altogether, AMS measurements at high fields and low temperatures allow for the discrimination of all three subfabrics. Test measurements with the high-field torque magnetometer at liquid nitrogen temperature were performed. It is possible to keep the specimens at low temperature over the measurement period using a cryostat. The main problem is the suppression of mechanical disturbances during the measurement so that the sensitivity of the instrument is retained. The torque of paramagnetic minerals increases strongly at low temperature which results in an amplification of the paramagnetic subfabric. The quantitative separation of diamagnetic and paramagnetic subfabric is under investigation. The result is promising when there is a significant diamagnetic signal.
    Description: conference
    Keywords: 551 ; TQB 000 ; TOT 310 ; VAE 120 ; Erdmagnetische Verfahren {Geophysik} ; Gesteinsmagnetismus {Geophysik} ; Methodik {Strukturgeologie} ; Magnetische Suszeptibilität ; Drehmagnetometer
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2021-03-29
    Description: Gravitative Massenverlagerungen entlang der Muschelkalkschichtstufe gehören zur natürlichen Morphodynamik. Durch die unterschiedliche Erosionsresistenz der relativ inkompetenten Ton- und Mergelsteine des Röt und der direkt darüber anstehenden widerstandsfähigeren Kalkgesteinen des Unteren Muschelkalks hat sich ein Steilhang im Übergang dieser Einheiten ausgeprägt. Ein unruhiges Relief des Schichtstufenhangs zeugt an vielen Stellen von gravitativen Massenverlagerungen. Zur detaillierten Kartierung dieser gravitativen Massenverlagerungen am Hünstollen im Göttinger Wald (10km nordöstlich von Göttingen) wurden Zweifrequenz-GPS-Messungen durchgeführt. Mittels differentieller Korrektur der gesammelten GPS-Daten konnte eine horizontale Präzision der Positionsbestimmung von bis zu 10 cm auf freier Fläche und bis zu 40 cm im Wald erreicht werden. Zusammen mit Schichtflächenmessungen ermöglichen die gesammelten Daten eine hochauflösende Darstellung einzelner Strukturelemente, Rückschlüsse auf die stattgefundenen Bewegungsabläufe sowie eine relative zeitliche Zuordnung der einzelnen Rutschkörper...
    Description: conference
    Keywords: 551 ; VEB 126 ; VDH 110 ; VDH 120 ; VAJ 100 ; VBG 100 ; Niedersächsisches Bergland {Geologie} ; Untere Trias ; Mittlere Trias ; Massenbewegungen {Geologie} ; Geologisches Kartieren ; Göttinger Wald ; Röt-Muschelkalk-Grenze ; Massentransport 〈Geowissenschaften〉 ; Kartierung
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2021-03-29
    Description: Im nördlichen Teil des Appenin in Italien ist der metamorphe Komplex der Alpi Apuane in Form eines tektonischen Fensters sehr gut aufgeschlosssen. Die metamorphen Gesteine der Alpi Apuane — Metakarbonate, Kiesel- und Karbonatschiefer sowie Phyllite — sind aufgrund der Kollision der korsischsardischen Mikroplatte mit der italienischen Halbinsel im mm bis km- Maßstab verfaltet worden. Im zentralen Teil der Alpi Apuane biegt das generelle N–S Streichen der Faltenstrukturen in eine E–W Richtung um. Faltenstrukturen mit senkrecht zueinander stehenden Faltenachsen sind charakteristisches Strukturmerkmal u.a. ‘Metamorpher Kernkomplexe’ und Schlüssel zum Verständnis von Deformationsgeschichte und mechanismen. Die Entwicklung dieser Strukturen wird kontrovers diskutiert...
    Description: conference
    Keywords: 551 ; VEF 200 ; VKB 292 ; VKB 270 ; VKA 200 ; VAE 140 ; VAE 120 ; Italien {Geologie} ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Produkte mechanischer Deformation {Petrologie} ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Methodik {Strukturgeologie} ; Apuaner Alpen ; Karbonatgestein ; Marmor ; Deformation 〈Geologie〉 ; Faltentektonik ; Gefüge 〈Gesteinskunde〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2021-03-29
    Description: Fission-track (FT) data always depend on the thermal history of a 3-D geological complex. Therefore it is expedient to display FT data sets in 3-D models. Such a model in which tectonic, sedimentological and hydrological features are combined can greatly improve the interpretation of the palaeo-thermal pattern derived from FT analyses. Since 1988 several FT studies have been conducted in the Black Forest (BF) (Michalski 1988, Wyss 2000, Timar- Geng et al. 2004, 2005). Timar-Geng et al. (2006) analyse the crystalline basement and the Permian Rotliegend beneath the Mesozoic units in the Tabular Jura (TJ) east of Basel, Switzerland, using samples taken from the three Nagra boreholes at Kaisten, Riniken and Leuggern. In particular Timar-Geng et al. (2005, 2006) characterise the thermal history of this pre-Mesozoic basement. For the BF they estimate at least one heating phase during the lower and middle Mesozoic while similar heating could not be observed in northern Switzerland. However, the FT-data in both regions show moderate to rapid cooling during the Cretaceous and Lower Eocene, which was followed by an Upper Eocene heating event. The software package GOCAD (Geological Objects Computer-Aided Design) was used to build a digital elevation model (DEM), which provide a new detailed view of these FT data sets. The model is located about 20 km east of Basel, Switzerland, and extends over an area of about 21km by 24 km and spans a vertical height difference of about 2 km. The data sets described above along with two additional FT analyses from the Buntsandstein which lies directly on the BF crystalline, were compiled and plotted at their topographic heights in the DEM. The FT central-ages (Galbraith & Laslett 1993) of this region range between 25 ± 2Ma and 98 ± 6.5 Ma. The topographic positions extend between −1412m at the Borehole Riniken and 960m in the BF with mean sea level as a reference. FT central-age isochron surfaces were drawn in order to visualize the thermal evolution within the model range. Because the FT central-ages also correspond to a closure temperature, these surfaces can also be considered an isotherm. The FT closure temperature of apatite is about 90±30°C (Laslett et al. 1987). Therefore each surface shows the position and shape of the ca. 90°C isotherm of a specific age. This 3-D model points out an important difference in the thermal evolution of the BF und the TJ. The vertical distance between the isothermal surfaces increases from north to south. Between 90Ma and 60Ma the ca. 90°C isotherm drops at the Kaisten borehole by 1000m while in the same time span in the BF a lowering of the same isotherm by 300m can be observed. In the eastern part of the model this feature is not as marked as in the west but nevertheless it is observable. To explain this entirely different thermal evolution it is necessary to turn to the tectonic and other geological features of the region. South of the exposed BF crystalline and beneath the TJ there lies an old Variscan structure: the Permo-Carboniferous trough (PCT). This trough strikes in WSWENE direction and extends from Lake Constance to the Bresse Graben and contains up to 6000m of Palaeozoic sediments. Additionally, some Variscan fault structures strike in WNW–ESE direction and cut both the BF an the PCT, for example the Eggberg Fault and the Vorwald Fault. Beside the tectonic structures the hydrological characteristics played an important role during the palaeo-thermal evolution. Circulating hot fluids controlled the thermal pattern. Variscan faults were often reactivated during the Mesozoic (e.g. Wetzel et al. 2003) and also during the formation of the Upper Rhine Graben. (e.g. Illies 1967) These faults are the major water-conducting features in the crystalline basement of the BF, joints and fracture networks are tributaries. Below the aquifers within the Mesozoic of the TJ, the PCT trough sediments predominantly act as an aquitard. Only the border faults of the trough were important pathways for fluids (Thury 1994). Considering the Mesozoic sedimentological history of the region it is unlikely that fault movements are responsible for the different palaeo-thermal pattern of the BF and the TJ. Only different magnitudes of heat flow caused by hydrothermal circulating fluids can explain the ‘warm’ BF crystalline in comparison to the ‘cold’ basement of the TJ at the transition between the Mesozoic and Tertiary.
    Description: conference
    Keywords: 551 ; VBN 500 ; VBN 200 ; VEB 143 ; Geochronologie einzelner Regionen im allgemeinen ; Radiometrische Altersbestimmung ; Oberrheinische Massen {Geologie} ; Schwarzwald 〈Südost〉 ; Kernspaltspurenmethode
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Regional strains in tectonically active volcanic provinces may have a profound influence on the mode of collapse caldera formation. Conversely, the deformation pattern, more specifically, the symmetry of plan-view strain fields imparted to caldera floors may assist in elucidating the regional deformation active during caldera formation. The symmetry of plan-view strain fields is chiefly controlled by the mode of floor subsidence, particularly whether subsidence is uniform, symmetric or asymmetric, portraying collapse mechanisms known respectively as plate, downsag and trapdoor. Plate and downsag subsidence generates centro-symmetric strain fields characterized by radial and concentric discontinuities and subvolcanic dikes. Such strain fields appear to develop preferably where magma pressure controls collapse. By contrast, rectilinear horizontal strain fields form under unidirectional stretching and generate normal faults and subvolcanic dikes transverse to the stretching direction. Rectilinear strain fields are typical for trapdoor subsidence but also for straight orogenic belts and suggests that the formation of both may be related. This was tested for six central Andean collapse calderas that formed between 10.5 and 2Ma and are located on prominent NW–SE striking fault zones. A combined geochronological and structural analysis of the Miocene Negra Muerta Caldera in particular was designed to better understand caldera formation associated with the prominent Olacapato – El Toro Fault Zone...
    Description: conference
    Keywords: 551 ; VAE 150 ; VEX 100 ; VAD 300 ; VAE 400 ; VAE 200 ; Strukturelle Erscheinungen {Strukturgeologie} ; Anden {Geologie} ; Vulkanformen und Vulkantypen {Geologie} ; Tektogenese {Geologie} ; Geodynamik der Lithosphäre {Geologie} ; Zentralanden ; Caldera ; Einsturzstruktur ; Deformation 〈Geologie〉 ; Geodynamik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2021-03-29
    Description: The Upper Rhine Graben forms the major segment of the Cenozoic Rift system of Western Europe. Although the rift was the target of many seismic and geological investigations, the style of lithospheric extension below the inferred faults, the depth to detachment, and the amounts of horizontal extension and lateral translation are still being debated. In this study, the date base to the Upper Rhine Graben was subjected to a finite element approach in order to include thermomechanical processes of the lithosphere as well as erosion and sedimentation. The study concentrated on the consequences of extension and lateral translational events on the structure and evolution in terms of basin geometry, sediment layer thicknesses, Moho elevation, and shoulder uplift on a lithospheric scale. The numerical approach was three dimensional in order to incorporate the lateral crustal heterogenities in the Upper Rhine area and the varying ambient stress field...
    Description: conference
    Keywords: 551 ; VEB 145 ; VAE 840 ; VAE 400 ; VAE 120 ; VBE 000 ; Rhein-Main-Tiefland {Geologie} ; Rifts {Geologie} ; Tektogenese {Geologie} ; Methodik {Strukturgeologie} ; Modellierung von Prozessen in der Geosphäre ; Oberrheingraben ; Tektonik ; Rifting ; Numerisches Modell
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2021-03-29
    Description: Der Ság-hegy Vulkan Komplex befindet sich in dem Vulkanfeld der Kleinen Ungarischen Tiefebene. Eine 39Ar/40Ar Datierung ergab ein Alter von 5, 42 ± 0, 06Ma für den Ság-hegy (Wijbrans et al. 2004). Die Entwicklung des Vulkans weist zwei verschiedene Ereignisse auf. Als erstes trifft aufsteigendes Magma auf meteorisches Wasser in einer fluviolakustinen Umgebung (fuel-coolant interaction FCI). Die FCI von Wasser bzw. wassergesättigtem Sediment und Magma führte zur Bildung eines phreatomagmatischen Tuffrings. Nachdem das Wasserangebot aufgebraucht war, füllte sich das Innere des Tephrarings mit einem Lavasee. Lokal kollabierte der Tuffring, so dass Lava aus dem See herausfließen konnte. Durch die Anlage eines Steinbruches im zentralen Bereich des Vulkankomplexes ergibt sich ein 3-D Aufschluss mit hervorragenden Einblick auf die Intrusionsbeziehungen von Förderdykes, Sills und Überresten des Lavasees (Martin & Németh, 2004). In dieser Studie sollen die magnetischen Charakteristika einer Sektion von pyroklastischen Gesteinen, die von Dykes und Sills abgeschnitten wird, untersucht werden. Vorläufige Ergebnisse zeigen, dass die magnetische Suszeptibilität aller pyroklastischen Einheiten im Bereich der ferrimagnetischen Suszeptibilität liegt und von (2 − 20 × 10−3 SI variiert...
    Description: conference
    Keywords: 551 ; VAD 500 ; VAD 700 ; VKB 128 ; TOT 320 ; TQB 000 ; TSE 000 ; VEE 200 ; Exhalationen und postvulkanische Erscheinungen {Geologie} ; Regionaler Vulkanismus {Geologie} ; Pyroklastika {Petrologie} ; Paläomagnetismus {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Südosteuropa {Geophysik} ; Pannonisches Becken {Geologie} ; Ungarische Tiefebene ; Pyroklastit ; Magnetische Suszeptibilität
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2021-03-29
    Description: Geology as a science has an important visual component and the knowledge of any geologist is deeply linked to visual experience of rock outcrops, thin sections and analytical images. One of the shortcomings of most geological images such as maps, cross sections and outcrop photographs is that they are 2D, while processes geologists are interested in are typically occurring in 3D space. The 3D geometry of faults, fractures and joints is crucial to quantify geological processes related to fracture mechanics, such as hydrothermal mineralization and ground water flow, but also geotechnical problems such as rock mass stability. A number of studies have shown that some geological structures can be described with a scale invariant, fractal distribution. So far these observations on which these findings are based were restricted to one and two dimensions and has been difficult to obtain a full spatial geometric picture of fracture sets from rock outcrops, because much of the rock is not directly accessible. However, without taking into account the spatial distribution of geological structures the true geometry of joint patterns cannot be fully described and scaling laws, fractal or not, cannot be derived. We present images of joint patterns based on datasets acquired by digital photographs which are processed to three dimensional images using the photogrammetry software Siro3D. This technique allows to obtain a highly accurate 3D picture of the visible outcrop. The spatial pattern of joints in nature is investigated using the software SiroJoint. For the analysis of joint systems a large data set was collected from the Heavitree Quarzite at Ormiston Gorge, near Alice Springs. The Heavitree Quartzite is fragmented by a spectacularly regular three-dimensional joint pattern, which is repeated at different scales and therefore represents a perfect laboratory for our investigations (Hobbs 1993). Siro3D generates a spatially fully referenced 3D image from overlapping digital images, such that each pixel of the image is assigned spatial coordinates. The software SiroJoint routinely constructs planes from the intersection of the rock-face with the linear trace of planar features (Poropat 2001). It provides stereographic plots of structural elements and additionally measures joint persistence, area, and joint spacing. Our measurements allow to analyse geometrical scaling relationships of joint sets with high accuracy and will help explore the character of their 3D complexity. Several hundred joint planes were defined with SiroJoint in an Ormiston Gorge outcrop. Three different joint sets can be distinguished. Joint set one and two are characterized by steeply inclined planes with joint spacings ranging between 2 cm to 40 cm and 2 cm to 10m respectively. Both joints sets depict a power law distribution in joint spacing/frequency plots. The third set is defined by a subhorizontal orientation. It shows a very regular spacing in the meter scale and lacks an exponential distribution. We intend to use the results as a basis to compare observed fracture pattern with those generated by computational methods like Iterated Function Systems. This might help to understand how physical rock properties influence the spatial complexity of fracture systems and develop constitutive scaling relationships for certain rock types.
    Description: conference
    Keywords: 551 ; VAE 120 ; VBH 000 ; VAE 150 ; Methodik {Strukturgeologie} ; Fernerkundung ; Strukturelle Erscheinungen {Strukturgeologie} ; Klüftung ; Bruch 〈Geologie〉 ; Photogrammetrie ; Dreidimensionale Rekonstruktion
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2021-03-29
    Description: Die Region - mit den markanten Erhebungen des Hohen Meißners und des Thüringer Waldes - stellt geologisch und bergbaugeschichtlich einen Teil der deutschen Mittelgebirge dar, der Fachleute sowie Amateure und Naturfreunde gleichermaßen fasziniert. Die vorliegende Bibliographie versucht erstmals länderübergreifend die umfangreiche Fachliteratur der Dreiländer-Region zu erschließen. Dabei wurden sowohl fachwissenschaftliche als auch heimatkundliche Publikationen und unveröffentlichtes Material berücksichtigt.
    Description: bibliography
    Keywords: 551 ; VEB 125 ; VEB 126 ; Hessisch-thüringisches Bergland {Geologie} ; Niedersächsisches Bergland {Geologie} ; Nordhessen ; Thüringen 〈West〉 ; Niedersachsen 〈Süd〉 ; Werra-Meißner-Kreis ; Geowissenschaften ; Bergbau ; Bibliographie ; 38.55 ; 57.01
    Language: German
    Type: monograph , publishedVersion , monograph
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2021-03-29
    Description: Grain boundary migration during dynamic recrystallization of quartz results in grain boundary suturing of various extent. The geometry of the sutured boundaries is affected not only by temperature, strain rate, finite strain and differential stress, but also by internal properties such as the defect distribution and crystallographic orientations. Consequently, the grain boundary geometry may provide information about these conditions and properties. In continuation of a previous study (Kuntcheva et al.) the complete crystallographic orientation of quartz grain boundaries was measured, based on a combination of electron backscatter diffraction (EBSD) and universal-stage (U-stage) measurements. For this purpose a sample of granite from the northern Aar Massif (Central Alps, Switzerland) was taken, deformed at temperatures up to 300–350°C at the end of the Lepontine event of the Alpine Orogenesis...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 120 ; VAE 130 ; Gefügekunde der Gesteine ; Methodik {Strukturgeologie} ; Geomechanik ; Aare-Massiv ; Granitgneis ; Quarz ; Rekristallisationstextur
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2021-03-29
    Description: Am Ostrand des Hauzenberger Plutons im südlichen Bayerischen Wald treten Ganggesteine auf, die spät- bis postvariskische Granitoide und ihre Rahmengesteine (anatektische und diatektische Gneise) durchschlagen. Die Intrusion der Gänge wurde auf 307Ma datiert (Siebel, pers. comm.). Sie stellen somit das jüngste magmatische Ereignis mit deutlichem zeitlichen Hiatus zur Platznahme der Granitplutone des Bayerischen Waldes zwischen 316 und 324Ma (Propach 2000) dar. Die Hauptverbreitung dieser Ganggesteine liegt in einem herzynisch verlaufenden Zug von Oberndorf im Nordwesten über Waldkirchen zum Oberfrauenwald und weiter nachWegscheid im Südosten. Die Gänge streichen in den zwei Hauptrichtungen WNW–ESE (etwa 140°), also in etwa parallel zum Bayerischen Pfahl, sowie annähernd N–S (etwa 170°). Die Gänge stehen generell saiger und haben Mächtigkeiten von wenigen dm bis zu 15 m. An 14 Gängen wurde im Gelände und Labor die magnetische Suszeptibilität gemessen.
    Description: conference
    Keywords: 551 ; VEB 211 ; VKB 130 ; TSB 000 ; TOT 310 ; TQB 000 ; VKA 200 ; Baden Württemberg {Geologie} ; Petrologie der Ganggesteine ; Mitteleuropa {Geophysik} ; Gesteinsmagnetismus {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Gefügekunde der Gesteine ; Bayerischer Wald ; Gang 〈Geologie〉 ; Magnetische Suszeptibilität ; Gefüge 〈Gesteinskunde〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2021-03-29
    Description: The Austroalpine microplate traces the Alpine collision event between the Africa-related southern Alpine realm and the European continent. The southern margin of this microplate, the basement to the north of Meran (including Texel unit and Schneeberg Zug) is characterized by regional eo-Alpine high-pressure metamorphism (Hoinkes & Thöni, 1987). PT conditions decrease from SE (Texel unit) to the pre-alpine basement in the NW. The HP Rocks were exhumed within a ca. 15km broad SW-NE-striking, NWdipping high strain zone (Sölva et al. 2001). The high-pressure Texel crystalline is tectonically underlain by the Campo unit in the south and overlain by the Ötztal-Stubai Basement in the north(west). The Schneeberg Zug forms an up to 5km thick shear zone at its base, representing the study area. It shows normal-sense kinematics and separates pre-Alpine basement rocks in the hanging wall from high-pressure rocks in the footwall, the Texel unit. These were emplaced on top of pre-Alpine basement rocks (Campo unit) by an eo-Alpine ductile thrust. Lithologically the western termination of the Schneeberg Zug comprises characteristic garnet micaschists, marble layers, amphibolites, quartzites, hornblende-garben-schists and calcschists. These lithologies are called Bunte Serie (Mauracher, 1981) and differ from the polyphase adjacent Texel unit and the polymetamorphic basement rocks in the hanging wall due to their lithological content and their monometamorphic evolution. Petrological and geochronological investigations on the eastern continuation of these characteristic metapelitic rocks evidence the time of garnet growth during D1 close to the Cretaceous pressure peak. Sm-Nd isochron data of these continuously zoned garnets yielded crystallization ages between 90 and 95 Ma. Preliminary structural investigations yielded four major deformation events: D1 produced a compositional layering and a mylonitic foliation; generally this ductile deformation in the northwestern portion of the Schneeberg Zug is characterized by contemporaneous shearing and folding forming isoclinal folds with axes oriented parallel to the NW–SE plunging stretching lineation. Deformation stage D2 formed tight folds with steep NW to WSW plunging axes and NW to W dipping axial planes, which refold the D1 related structures. Deformation stage D3 is characterized by a crenulation with NW-plunging axes and NW-dipping axial planes. Lower greenschist-facies shear-zones dipping to the W and with shear sense top to W– WNW represent the last ductile event. They crosscut the older structural inventory. Brittle deformation evidences normal faulting reactivating the NW dipping main foliation as well as related dextral strike slip movement. Geochronological data and structural investigations indicate a continuous eo- Alpine tectono-metamorphic evolution, which started at high grade conditions homogenously distributed over the whole shear zone. With decreasing temperature conditions the deformation progressively partitioned into distinct shear zones.
    Description: conference
    Keywords: 551 ; VEB 163 ; VAE 150 ; VAE 850 ; VKB 291 ; Zentrale Ostalpen {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Festländische Lineamente {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Südtirol ; Campo-Kristallin ; Scherzone
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2021-03-29
    Description: Die Exkursion stellt repräsentative Aufschlüsse triassischer und jurassischer Sedimente aus der direkten Umgebung von Göttingen vor. Dabei werden deren stratigraphische Stellung, Ablagerungsmilieus und Fossilgemeinschaften diskutiert. Zunächst werden Aufschlüsse auf der östlichen Schulter des Leinetalgrabens (Muschelkalk- Plateau des Göttinger Waldes), danach auch im Leinetalgraben selbst (Keuper, Schwarzjura) besucht. Hinreichend gute Aufschlußbedingungen sind vor allem in Tongruben (Röt, Mittlerer Keuper, Schwarzjura) und Steinbrüchen (Unterer Muschelkalk) gegeben.
    Description: excursionguide
    Keywords: 551 ; VEB 126 ; VDH 100 ; VDH 200 ; Niedersächsisches Bergland {Geologie} ; Trias ; Jura ; Göttingen ; Geologie ; Trias ; Jura 〈Geologie〉 ; 38.10
    Language: German
    Type: article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2021-03-29
    Description: Basement-cover-interfaces are important crustal boundaries. In many cases they act as detachment horizons. Criteria like pre-erosional basement characteristics, intensity of palaeoweathering and post-erosional processes during burial stage lead to a huge variety of observable alteration and fabric features of basement-cover-interfaces, which may influence the shear-strength. Unconformity-parallel planar fabrics in the weathering profile were facilitated by palaeo-alteration and later processes (Angerer 2005 unpubl. data). Such fabrics may be a factor for lowering the shear-strength (e.g. Wintsch et al. 1995). The probably ubiquitous existence of those fabrics at basement-coverinterfaces is investigated in case studies by means of AMS-fabric analysis, which is a sensitive indicator of rock fabric changes. The present case study is based on sections from two drill cores across the erosional unconformity between Fennoscandian Granite (Revsund) and Cambrian Gärdsjön Fm. (Långviken SGU 73007 and Hara 79002) (petrographic descriptions in Gee, 1978 and Gee et al. 1982).
    Description: conference
    Keywords: 551 ; VAH 000 ; VAE 813 ; TOT 310 ; VED 200 ; Verwitterung {Geologie} ; Kaledonische Orogene {Geologie} ; Gesteinsmagnetismus {Geophysik} ; Schweden {Geologie} ; Mittelschweden ; Kaledoniden ; Verwitterungshorizont ; Magnetische Anisotropie ; Gesteinsgefüge ; Magnetische Suszeptibiblität
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2021-03-29
    Description: The suevitic Onaping Formation overlies the layered Main Mass of the 1.85Ga Sudbury Igneous Complex (SIC) of the Sudbury Impact Structure, Ontario. The Formation consists of four Members, namely from top to bottom, the Black, the Green, the Gray and the Basal. Post-impact NWSE shortening during the Penokean Orogeny (ca. 1.9–1.75 Ga) affected the Onaping Formation and led to the lobate shape of the SIC in plan view. In order to investigate the possible fold origin of the NE-lobe of the SIC, a field-based structural analysis of the Onaping Formation was conducted in the Frenchman Lake area. The analysis is based on structural measurements at 580 stations and encompasses the orientation of mineral shape fabrics as well as their intensity. In addition to these quantities, lithological variation and metamorphic overprint of the Onaping Formation was examined. Special attention was paid thereby to the Green Member since previous workers stated that it forms a continuous unit at the base of the Black Member...
    Description: conference
    Keywords: 551 ; VKB 280 ; VKB 295 ; VAE 140 ; VEV 127 ; VKA 200 ; Impaktgesteine {Petrologie} ; Metamorphe Komplexe, Nordamerika {Petrologie} ; Gesteinsdeformation {Strukturgeologie} ; Ontario {Geologie} ; Gefügekunde der Gesteine ; Sudbury 〈Ontario. Region〉 ; Mehrfachringbassin ; Proterozoikum ; Impaktmetamorphes Gestein ; Suevit ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2021-03-29
    Description: Lokalisierung unter retrograden Deformationsbedingungen kann häufig in groß-maßstäblichen Scherzonen beobachtet werden. Dabei nimmt die Scherzonenbreite kontinuierlich ab. Gleichzeitig passt sich das Gefüge (Korngröße, Kornform, Kornorientierung, Zwillingsdichte, kristallographische Orientierung, usw.) den neuen Umgebungsbedingungen (Temperatur, Spannung und Verformungsrate) an. Die Glarner Hauptüberschiebung in den Ostschweizer Alpen ist ein gutes Beispiel, um das Ausmaß und die Entwicklung einer Verformungslokalisierung zu bestimmen. In der Vergangenheit wurde sie detailliert in Hinblick auf ihre Isotopenverteilung und daraus resultierenden Fluidbewegungen und Überprägungen untersucht. Dies erlaubt das Zusammenspiel der Lokalisierung und der Fluidüberprägung zur Zeit der Platznahme der Glarnerdecke zu bestimmen...
    Description: conference
    Keywords: 551 ; VAE 130 ; VAE 400 ; VAE 150 ; VJC 400 ; VEB 168 ; Geomechanik ; Tektogenese {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Fluid-Gestein-Wechselwirkungen {Geochemie} ; Schweizer Alpen {Geologie} ; Glarner Alpen ; Scherzone ; Deformation 〈Geologie〉 ; Fluid-Fels-System
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2021-03-29
    Description: Als Teil des International Continental Drilling Projects (ICDP), wurde von März bis September 1999 im Rahmen des Hawai’i Scientific Drilling Projects (HSDP) die etwa 3109m tiefe HSDP-2 Bohrung in der Nähe von Hilo auf Big Island, Hawai’i niedergebracht. Die mit einem Durchmesser von 98mm (3.8500) durchgehend gekernte Bohrung, durchteuft sowohl die subaerischen Einheiten des Mauna Loa, als auch die darunter liegenden submarinen Laven des Mauna Kea. Ab etwa 1080m Teufe wurden die jüngsten, während der Entwicklung dieses Vulkans abgelagerten submarinen Laven erbohrt. Die Verteilung von Hyaloklastiten, Pillowlaven, massiver Intrusiva sowie sedimentärer Ablagerungen, wurde durch die lithologische Beschreibung des durchgehend geförderten Kernprofils von DePaolo et al. (1999) aufgenommen. Verschiedene Autoren, wie z.B. Bücker et al. (1999) oder Helm-Clark et al. (2004) haben bereits gezeigt, dass sich Messungen der natürlichen Gammastrahlung (GR), die üblicherweise sehr gut zur lithologischen Einteilung von Gesteinen herangezogen werden können, in vergleichbaren Bohrungen nur sehr bedingt zur primären Unterscheidung basaltischer Gesteinseinheiten eignen. Dies ist vor allem auf die sehr geringe Variation des K-, U- und Th-Gehalts der Basalte zurückzuführen. Daher wurden von der Operational Support Group (OSG) des GFZ-Potsdam im November 2002 bohrlochgeophysikalische Messungen in dem 98mm Bohrloch in einem Bereich von etwa 1830 bis 2615m durchgeführt. Diese wurden speziell zum Test einer Bohrlochsonde zur Messung der magnetischen Suszeptibilität (MS) im Rahmen des DFG-Projektes Wa 1015/4 angesetzt. Dazu wurde die MSdH-2 Sonde der OSG, hergestellt von der Fa. Antares GmbH (Stuhr, Germany) eingesetzt.
    Description: conference
    Keywords: 551 ; VAD 400 ; TOT 310 ; TQG 000 ; VEV 285 ; VBL 500 ; VKB 124 ; Vulkanische Förderprodukte {Geologie} ; Gesteinsmagnetismus {Geophysik} ; Geophysikalische Bohrlochmessungen ; Hawaii {Geologie} ; Geologische Bohrungen in einzelnen Regionen ; Basaltische Vulkanite {Petrologie} ; Mauna Kea ; Tiefbohrung ; Bohrlochgeophysik ; Magnetische Suszeptibilität ; Lava ; Basalt
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2021-03-29
    Description: Dykes are magma-driven extension fractures and the main conduits for magma in volcanic eruptions. To understand the mechanics of dyke emplacement is thus essential to assess volcanic hazards. To improve the understanding of the processes of dyke initiation from shallow magma chambers and dyke propagation through a mechanicallylayered crust, field measurements and observations from Tenerife (Canary Islands) are used and compared with the results from numerical models. Careful studies of 550 dykes in three profiles in the Anaga massif (Tenerife) include measurements of dyke geometry and orientation. The results of these measurements show that dykes have been injected from a deep-seated reservoir during the shield-building phase. Furthermore, the dyke attitudes agree with the main axial trends of Tenerife that are preserved in the old massifs of Teno, Anaga, and Roque del Conde...
    Description: conference
    Keywords: 551 ; VAE 150 ; VEZ 130 ; Strukturelle Erscheinungen {Strukturgeologie} ; Inselgruppen {Atlantischer Ozean: Geologie} ; Teneriffa ; Gang 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2021-03-29
    Description: The North Equatorial Panafrican belt is constituted by orthogneissified metamorphic and magmatic sets linked to tectonometamorphic events of the neoproterozoic orogeny. This belt whose formations are situated in the North of the congo craton is divided into three distinct geodynamic domains: a southern domain, a northern domain and a central domain. The deformation and metamorphism relationships are a function of the different geodynamic domains of the belt. The central domains, to which belongs the Banefo region, is affected by large strike-slip faults among which is the central cameroonian shear zone. This domain is marked out by numerous syntectonic granitoids. At Banefo (NE Bafoussam, West Cameroon), those massifs are mainly constituted by mylotinised orthogneisses and granites of various degrees. The country rock is made up of gneiss and amphibolite. In the Banefo massifs, the orthogneiss is the least deformed petrographic unit. It shows a heterogranular granoblastic texture with a mineral assemblage formed by quartz, K-feldspars, biotite, etc., within the orthogneiss, remains of magmatic fluidality can still be observed marked by feldspar megacrystal. Field observations reveal a net progression of the intensity of deformation of orthogeisses to ultramylotinised granites having an identical chemical composition as the orthogneisses...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 140 ; VAE 850 ; VKB 270 ; VEP 500 ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Festländische Lineamente {Geologie} ; Produkte mechanischer Deformation {Petrologie} ; Kamerun {Geologie} ; Kamerun-Linie ; Granitgneis ; Mylonit ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2021-03-29
    Description: The geothermal field at Reykjanes peninsula is located at the boundary where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The geothermal field coincides with a magnetic low in the aeromagnetic anomaly map and is situated within a dense NE–SW fissure and fault zone. Surface geology is characterized by different historic fissure eruptions (youngest from 1226AD), shield lava (12.5–14.5 ka) and intercalated pillow basalt–hyaloclastite ridges probably formed during the last glacial episode (14.5–20 ka). During a field magnetic study in the vicinity of the geothermal field in summer 2005 different volcanic rock units have been sampled to correlate rock magnetic and magneto-mineralogical properties with magnetic field intensity. Additionally, measurements on a dense dolerite intrusion, recovered from the RN–19 borehole (2245–2248m depth) in May 2005 within the frame of IDDP, should shed light on the influence of crustal rocks on the total magnetic field intensity. Generally, the natural remanent magnetization and magnetic susceptibility, measured on rock specimen, is high, ranging between 2.5 and 33.6Am−1 and 2–37 ×10−3 SI, respectively...
    Description: conference
    Keywords: 551 ; TOT 320 ; TSZ 100 ; TSD 000 ; TQB 000 ; VED 500 ; VEZ 110 ; VAE 890 ; VKA 150 ; VKB 326 ; Paläomagnetismus {Geophysik} ; Atlantischer Ozean {Geophysik} ; Nordeuropa {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Island {Geologie} ; Teilgebiete {Geologie} ; Ozeanische Kruste {Tektonik} ; Physikalische Petrologie ; Magnetische Stratigraphie {Sedimentologie} ; Reykjanes ; Reykjanesrücken ; Ergussgestein ; Magnetische Suszeptibilität ; Magnetostratigraphie
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2021-03-29
    Description: Der oberflächennahe geologische Untergrund Norddeutschlands wird durch das Auftreten zahlreicher Salzvorkommen geprägt. Während der Triaszeit und des unteren Juras herrschte ein EW gerichtetes, extensives tektonisches Regime vor. Durch zusätzliche Umlagerung klastischer Sedimente wurden darunter liegende Salzmassen permischen Alters (Zechstein) aus Tiefen von bis zu 5000Metern an die Erdoberfläche empor gepresst. Durch diesen Salzaufstieg wurden darüber liegende mesozoische Schichten durchschlagen, randlich der Salzdiapire deformiert und teilweise mitgeschleppt. Eine letzte Phase salztektonischer Aktivitäten während der oberen Kreide und des unteren Tertiärs zeichnet sich zum einen durch weiteren Salzaufstieg aus und zum anderen durch horizontale Einengung der Salzstöcke. Begleitgesteine der Salze, wie Gips, Anhydrit, und Karst, sowie Tertiäre und Quartäre Ablagerungen überlagern die Salzstöcke mit unterschiedlichen Mächtigkeiten. Das humide Klima Norddeutschlands begünstigt natürliche Auslaugungsprozesse (Subrosion) der Evaporite durch Grundwasser. Je nach Tiefenlage des Salzspiegels (Salzstock Lüneburg: −20 bis −40 m; Salzstock Othmarschen-Langenfelde (Hamburg): ca 0 bis −250 m) kann es zu intensiver Hohlraumbildung im tieferen Untergrund kommen. Die fortschreitende Vergrößerung einer solchen Höhle steht in Abhängigkeit zur Intensität der Lösungsprozesse, während die Stabilität des Hohlraumes zusätzlich von der Materialbeschaffenheit abhängt. So können feste Gesteine oder bindige Böden zwar ein stabiles Höhlendach bilden, jedoch ist bei andauernden Lösungsprozessen langfristig ein statisches Versagen des Höhlendaches unvermeidlich. Der damit verbundene Kollaps und die Verfüllung des Hohlraumes mit Sediment spiegelt sich häufig in Form von sub-zirkularen und konischen Einsturzröhren oder weitläufigen morphologischen Trichtern an der Erdoberfläche wieder. Die Terminologie der Erdfälle wird anhand der Subsidenzrate gewählt...
    Description: conference
    Keywords: 551 ; TQD 800 ; VAO 120 ; VEB 110 ; Georadar {Geophysik} ; Karsterscheinungen an der Erdoberfläche ; Norddeutsche Senke {Geologie} ; Hamburg 〈Region〉 ; Lüneburg 〈Region〉 ; Erdfall ; Elektromagnetische Reflexionsmethode ; Risikoanalyse ; Salztektonik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2021-03-29
    Description: Structural analysis of Paleozoic Middle and Upper Austroalpine (MAA, UAA) units of the Gurktal Nappe Complex (GNC) in combination with electron microprobe analyses of multiphase garnets reveal a complex Variscan and Alpidic tectonometamorphic evolution of the GNC. Our study is focussed on the UAA ‘Murau Nappe’ and its tectonic transition to the MAA respectively to the overlying UAA Stolzalpen Nappe. The ‘Murau Nappe’ may rather be interpreted as a major zone of imbricate thrust slices of the underlying and overlying units than a distinct nappe. The results of our study lead to a reinterpretation of the ‘Murau Nappe’ as a major shear zone generated during the Eo-Alpine thrusting of the Stolzalpen Nappe over the MAA. Concerning the central GNC we conclude, that the genetic term ‘Murau Nappe’ for the lower UAA unit between MAA and Stolzalpen Nappe is not valid. Instead, its reinterpretation as a major shear zone (‘Murau shear zone’), genetically belonging to the MAA, generated during Eo-Alpine overthrusting of the Stolzalpen Nappe, is favoured. The Mesozoic Stangalm unit is interpreted as a local sequence imbricated during the northward movement of the MAA units.
    Description: conference
    Keywords: 551 ; VEB 163 ; VAE 400 ; VKB 291 ; VAE 811 ; Zentrale Ostalpen {Geologie} ; Tektogenese {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Alpidische Orogene {Geologie} ; Gurktaler Decke ; Alpidische Gebirgsbildung ; Tektogenese ; Metamorphose 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2021-03-29
    Description: Structural analysts are often faced with the problem of identifying prominent structural discontinuities covered by post-tectonic sedimentary or volcanic rocks. Gravity fields are often used to delineate the trace of buried discontinuities but are frequently found to be too crude to localize discontinuities adequately. Here, we introduce the importance of dip curvature of the isostatic residual gravity for identifying upper-crustal discontinuities. The relationship between Bouguer gravity, isostatic residual gravity and its dip curvature, first-order structural elements and distribution of Neogene volcanic rocks was examined in the central Andean plateau, more specifically, the southern Altiplano and the Puna...
    Description: conference
    Keywords: 551 ; TSX 000 ; TQA 000 ; VAE 811 ; VEX 100 ; Südamerika {Geophysik} ; Gravimetrische Verfahren {Geophysik} ; Alpidische Orogene {Geologie} ; Anden {Geologie} ; Zentralanden ; Erdkruste ; Diskontinuität 〈Geologie〉 ; Gravimetrie
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2021-03-29
    Description: Der Holozäne Thingvellir Spaltenschwarm ist Teil des 60 km langen Hengill Vulkansystems, das sich in der Westvulkanischen Zone in Island befindet und ein etwa 9000 Jahre altes basaltisches Lavafeld nördlich des Sees Thingvallavatn durchquert. Dieser Spaltenschwarm enthält einige der größten postglazialen Verwerfungen und Brüche, die in der Riftzone Islands anzutreffen sind. Das Zentrum des Hengill Vulkansystems bildet der 0.8 Ma alte gleichnamige Vulkan. Der Gipfel des Vulkans ist durchzogen von NE-SW streichenden Abschiebungen, von denen einige bis zum See Thingvallavatn verfolgt werden können. Der Thingvellir Spaltenschwarm wird von nahezu vertikalen Zugbrüchen und geöffneten Abschiebungen dominiert...
    Description: conference
    Keywords: 551 ; VAE 830 ; VAE 150 ; VED 500 ; Bruchschollenstrukturen {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Island {Geologie} ; Island ; Thingvellir ; Abschiebung 〉Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2021-03-29
    Description: Die Insel Kreta bildet den südlichen Rand der externen Helleniden, welche üblicherweise in zwei Deckenstapel untergliedert werden: Die unteren Decken (Plattenkalk und Phyllit-Quarzit- Einheit) sind durch eine alpidische HP-Metamorphose (Oligozän/Miozän) gekennzeichnet (Seidel et al. 1982, Jolivet et al. 1996), welche im Hangenden bislang nicht nachgewiesen wurde. Die Oberen Decken (i.w. Tripolitza- und Pindos-Einheit) bestehen aus karbonatischen Gesteinen und sind für eine petrologische PT-Abschätzung ungeeignet. Aufgrund des Gesteinshabitus wurden sie als unmetamorph eingestuft. Schlußfolgernd wird der Kontakt der beiden Stapel seit etwa zwanzig Jahren als krustales Megadetachment (‚Kreta- Detachment‘) aufgefaßt (Jolivet et al. 1996, Fassoulas et al. 1994, Kilias et al. 1994), wobei Versatzbeträge von über 100km angenommen werden (Ring et al. 2001, 2001). Ziel dieser Arbeit ist es Gemeinsamkeiten und Unterschiede der unmittelbar an das Detachment angrenzenden Einheiten herauszuarbeiten, um Rückschlüsse auf die tatsächliche Signifikanz der Störungszone zu ziehen.
    Description: conference
    Keywords: 551 ; VEF 000 ; VAE 140 ; VAE 400 ; VKA 200 ; VKB 292 ; VKB 250 ; Südeuropa und Mittelmeergebiet {Geologie} ; Gesteinsdeformation {Strukturgeologie} ; Tektogenese {Geologie} ; Gefügekunde der Gesteine ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Metasedimente {Petrologie} ; Kreta ; Abscherung ; Deformation 〈Geologie〉 ; Alpidische Gebirgsbildung ; Metamorphose 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2021-03-29
    Description: The EZ is an approximately 20km long and 2–3km wide coherent unit of the Tauern Window in the Eastern Alps. It is sandwiched between the Venedigerand the Glockner Nappe. While rocks in the EZ experienced HP metamorphic conditions (24 kbar/650°C), rocks from the underlying Venediger Nappe and the overlying Glockner Nappe only record lower alpine metamorphic conditions with peak pressures not exceeding 10 and 8 kbar, respectively. While metamorphism in the EZ is well dated with an average age of 31.5±0.7Ma (Glodny et al. 2005) the final emplacement of these different nappes is still under debate. Our Rb-Sr-data indicate that top-N thrusting at the base and large-scale folding of the EZ was coeval with sinistral strike-slip faulting at its upper boundary and eclogite-facies metamorphism in the EZ. The data also indicate that today’s nappe architecture must have been established in less than 2Ma after the eclogite facies metamorphism in the EZ. Very fast exhumation of the EZ was accomplished in a transpressional setting, which might explain why the exposed EZ is such a small unit.
    Description: conference
    Keywords: 551 ; VEB 163 ; VKB 291 ; VAE 400 ; VBN 500 ; VAE 811 ; Zentrale Ostalpen {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Tektogenese {Geologie} ; Geochronologie einzelner Regionen im allgemeinen ; Alpidische Orogene {Geologie} ; Tauernfenster ; Decke 〈Geologie〉 ; Eklogit ; Rubidium-Strontium-Methode ; Überschiebung ; Oligozän
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2021-03-29
    Description: During impact, rocks at the surface and accessible depths encounter extreme conditions. The hydrostatic component of the shock wave-associatedstress, the so-called shock pressure, canreach several tens of GPa in the central part of the structure. The shock crust and its comprehensive experimental calibration. Two distinct types of quartz microstructure in charnockitic target rocks and quartz veins of the Charlevoix impact structure are compared and contrasted in order to distinguish shock-induced microstructures that indicate a high hydrostatic stress component of the shock wave-associated stress from those that indicate a high deviatoric component, as well as associated microstructures that were generated during post-shock relaxation...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 140 ; VHB 400 ; VKB 280 ; VEB 128 ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Oxide und Hydroxide {Mineralogie} ; Impaktgesteine {Petrologie} ; Saxothuringikum {Geologie} ; Charlevoix 〈Quebec〉 ; Impaktstruktur ; Impaltmetamorphes Gestein ; Deformation 〈Geologie〉 ; Quarz ; Mikrostruktur
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2021-03-29
    Description: The tectonic history of the Kamchatka Peninsula is dominated by continuous accumulation and amalgamation of terranes with different origins, which were delivered by convergence between the Pacific plate and in former times, the Kula plate against Eurasia (Freitag, 2002). The Kronotsky and Cape Kamchatka Peninsulas show that the collision of terranes and the resulting tectonics are still important for major parts of East-Kamchatka. While the collision of the Kronotsky Peninsula is sorely influenced by the convergence of the Pacific plate, the Cape Kamchatka Peninsula is affected by the collision of the Aleutian Arc with Kamchatka, what gives the opportunity to compare two different processes that resulted in the amalgamation of terranes to Kamchatka.
    Description: conference
    Keywords: 551 ; VEG 190 ; VAE 400 ; VAE 300 ; VAE 120 ; VBJ 000 ; Koriakia-Kamtchatkasystem {Geologie} ; Tektogenese {Geologie} ; Epirogenese {{Geologie}} ; Methodik {Strukturgeologie} ; Satellitenbildgeologie ; Kamtschatka 〈Oblast〉 ; Neotektonik ; Fernerkundung
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2021-03-29
    Description: The radiogeic 4He isotope is continuously forming in the lithosphere mainly by the alpha-decay of U, Th and Sm. This decay process was discovered already at the beginning of the 20th century, and the first U/He dating was made by Rutherford (1905). Although his result indicated that the dimensions of the Earth’s history ranges to millions of years, the U/He method was used only scarcely later on because the minerals are usually not closed to the decay product. The helium is extremely mobile and diffuse through the crystal lattices. Thus, the apparent U/He ages were always younger than the radiometric ages determined by other isotope geochronometers like U/Pb, Rb/Sr or K/Ar. The current renaissance of the method has been started at the end of eighties, when H. Lippolt, P. Zeitler, K. Farley and their co-workers have described the parameters of diffusion of some uraniumbearing minerals (e.g. Lippolt & Weigel 1987, Zeitler et al. 1987). It turned out that the (U-Th)/He apparent ages do carry meaningful geological information. The closure temperature of the most widely used apatite-He system is around 70°C. Thus, by the usage of this mineral/method pair it became possible to date low-temperature geological processes, which were undatable by other geochronometers...
    Description: conference
    Keywords: 551 ; VBN 200 ; VBN 500 ; VEB 164 ; Radiometrische Altersbestimmung ; Geochronologie einzelner Regionen im allgemeinen ; Südalpen {Geologie} ; Helium-Methode ; Thermochronologie ; Südalpen
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2021-03-29
    Description: In den vergangenen Jahren wurden von den Mitgliedern unseres Departments mehrere Feldstudien über elektromagnetische Emissionen in tektonisch aktiven Regionen durchgeführt. Die Untersuchungsgebiete lagen in Südspanien, Sizilien, Malta, Eger-Graben/Tschechische Republik und die Provence/Frankreich als auch in Süd-Chile. Das Ziel dieser Untersuchungen war die Erfassung der größten horizontalen Spannungs-Richtung in der oberen Erdkruste. Dazu wurden die Intensität des elektromagnetischen Feldes in Bezug zu der Orientierung einer Richtantenne gemessen. Diese Ergebnisse wurden mit aktiven Stress-Richtungen verglichen die aus Doorstopper-Messungen, Bohrloch- Randausbrüchen, Herdflächenlösungen und neotektonischen Strukturanalysen gewonnen wurden. Die Richtungen der größten Horizontalspannungen stimmen sehr gut mit der Orientierung der maximalen elektromagnetischen Emission überein.
    Description: conference
    Keywords: 551 ; VAE 120 ; VAE 130 ; TQD 000 ; Methodik {Strukturgeologie} ; Geomechanik ; Elektrische Verfahren {Geophysik} ; Erdkruste ; Spannung 〈Geologie〉 ; Spannungszustand ; Elektromagnetisches Verfahren
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2021-03-29
    Description: Der Aufsatz beschreibt die geowissenschaftlichen Sondersammelgebiete der Niedersäschsischen Staats- und Universitätsbibliothek Göttingen und die Entwicklungsgeschichte internetbasierter Informationssysteme für die Geowissenschaften.
    Description: report
    Keywords: 551 ; V 200 ; Wissenschaftsorganisation und -Pflege {Geologische Wissenschaften} ; Göttingen ; Niedersächsische Staats- und Universitätsbibliothek ; Geowissenschaften ; Sondersammelgebiet ; Virtuelle Bibliothek ; 38.04
    Language: German
    Type: article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2021-03-29
    Description: Die Region - mit den markanten Erhebungen des Hohen Meißners und des Thüringer Waldes - stellt geologisch und bergbaugeschichtlich einen Teil der deutschen Mittelgebirge dar, der Fachleute sowie Amateure und Naturfreunde gleichermaßen fasziniert. Die vorliegende Bibliographie versucht erstmals länderübergreifend die umfangreiche Fachliteratur der Dreiländer-Region zu erschließen. Dabei wurden sowohl fachwissenschaftliche als auch heimatkundliche Publikationen und unveröffentlichtes Material berücksichtigt.
    Description: bibliography
    Keywords: 551 ; VEB 125 ; VEB 126 ; Hessisch-thüringisches Bergland {Geologie} ; Niedersächsisches Bergland {Geologie} ; Nordhessen ; Thüringen 〈West〉 ; Niedersachsen 〈Süd〉 ; Werra-Meißner-Kreis ; Geowissenschaften ; Bergbau ; Bibliographie ; 38.55 ; 57.01
    Language: German
    Type: monograph , publishedVersion , monograph
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2021-03-29
    Description: Metamorphic rocks approaching the crustal scale brittle-ductile transition (BDT) during exhumation are expected to become increasingly affected by short term stress fluctuations related to seismic activity in the overlying seismogenic layer (schizosphere), while still residing in a long-term viscous environment (plastosphere). The structural and microstructural record of quartz veins in low grade – high pressure metamorphic rocks from southern Evia, Greece, yields insight into the processes and conditions just beneath the long-term BDT at temperatures of about 300 to 350°C, with switches between brittle failure and viscous flow as a function of imposed stress or strain rate...
    Description: conference
    Keywords: 551 ; VAE 400 ; VAE 150 ; VKB 130 ; VEF 300 ; Tektogenese {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Petrologie der Ganggesteine ; Griechenland und griechische Inseln {Geologie} ; Euböa ; Krustenbewegung ; Hydraulische Rissbildung ; Bruch 〈Geologie〉 ; Quarzgang
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2021-03-29
    Description: Oceanic transform faults and ridge segments form a network where mechanical interaction is to be expected. In particular, dike emplacement in ridge segments is likely to affect earthquake activity in the adjacent transform faults through processes such as stress transfer. Similarly, strike-slip displacement across transform faults may trigger dike injections and, eventually, eruptions in the adjacent ridge segments. For obvious reasons, direct observations of the possible mechanical interaction between submarine transform zones and ridge segments at mid-ocean ridges are difficult. The subaerial seismic zones of Iceland, however, are in clear spatial connections with the adjacent volcanic zones. These zones, therefore, provide excellent opportunities to study stress transfer between volcanic and seismic zones (Gudmundsson 2000)...
    Description: conference
    Keywords: 551 ; VAE 130 ; VAE 200 ; TOH 520 ; VAD 200 ; Geomechanik ; Geodynamik der Lithosphäre {Geologie} ; Mechanismen von Erdbeben und seismischen Störungen {Geophysik} ; Vulkanische Tätigkeit {Geologie} ; Island ; Horizontalverschiebung ; Vulkanismus ; Induzierte Seismizität
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2021-03-29
    Description: Geophysikalische Untersuchungen im Gebiet der Grube Messel (25km südlich von Frankfurt) ließen schon vor einigen Jahren eine Maar-Diatrem-Struktur im Untergrund vermuten. Jedoch erst die gekernte Forschungsbohrung im Jahr 2001 bewies die Existenz eines durch phreatomagmatische Eruptionen gekennzeichneten Maar- Vulkans, der vor ca. 48Ma aktiv war. Neben den berühmten fossilreichen Ölschiefern wurde im Teufenbereich zwischen −240m und −370m unter der Erdoberfläche vulkaniklastisches Material entdeckt. Unterhalb des so genannten Lapillituffs wurden bis zur Endteufe von −433m Gesteine der Diatrem-Brekzie erbohrt. Um das schwer differenzierbare, vulkanische Gestein in situ detaillierter untersuchen zu können, sind gesteinsmagnetische Messungen besonders wertvoll. Hierbei kann die magnetische Suszeptibilität (MS), die Magnetisierbarkeit eines Gesteins, für quantitative und qualitative Analysen sehr hilfreich sein. Die juvenilen Lapilli, an die die ferrimagnetischen Minerale bzw. die magnetischen Träger gebunden sind, sind dabei von besonderem Interesse. Bildanalytische Auswertungen sowohl an Kernen als auch an Dünnschliffen dienen dabei zur Interpretation des Suszeptibilitätslogs der durchgeführten Bohrlochmessungen. In dieser Studie ist weiterhin ein besonderes Augenmerk dem magnetischen Gefüge der Vulkaniklastika verliehen. Dabei liefern Messungen der Anisotropie der magnetischen Suszeptibilität (AMS) Informationen über die räumliche Anordnung der magnetischen Minerale (Foliation und Lineation) und offenbaren dadurch interne Strukturen des Gesteins.
    Description: conference
    Keywords: 551 ; VAD 700 ; TOT 310 ; VAD 400 ; TQG 000 ; TSB 000 ; VEB 149 ; Regionaler Vulkanismus {Geologie} ; Gesteinsmagnetismus {Geophysik} ; Vulkanische Förderprodukte {Geologie} ; Geophysikalische Bohrlochmessungen ; Mitteleuropa {Geophysik} ; Tertiäre Vulkangebiete und Nördlinger Ries {Geologie} ; Messel Grube ; Maar ; Bohrlochmessung ; Vulkanoklastische Ablagerung ; Magnetische Suszeptibilität ; Pipe 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2021-03-29
    Description: Granitic gneisses of the Central Aar Granite host a shear zone network that formed at greenschist facies conditions. The work area is located in the Bächlital (Grimsel area, Central Switzerland) and was chosen for the analysis of shear zones because of the weakly anisotropic fabric of the host gneisses. Contrary to previous publications (e.g. Choukroune & Gapais, 1983), none of these host rocks are undeformed. They contain a penetrative foliation (S1) that strikes consistently ENE-WSW with a steep dip of around 70° to the south. This foliation is overprinted by the aforementioned shear zone network, which was the main focus of this study...
    Description: conference
    Keywords: 551 ; VAE 140 ; VKA 200 ; VKB 291 ; VEB 168 ; VKB 230 ; VKB 270 ; Gesteinsdeformation {Strukturgeologie} ; Gefügekunde der Gesteine ; Metamorphe Komplexe, Alpen {Petrologie} ; Schweizer Alpen {Geologie} ; Metamorphite aus sauren bis intermediären Edukten {Petrologie} ; Produkte mechanischer Deformation {Petrologie} ; Aarmassiv ; Scherzone ; Granitgneis ; Feldspäte ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2021-03-29
    Description: Fluid overpressures are well known from hydrocarbon exploration in many sedimentary basins. They can reach almost lithostatic values, and may cause the fracturing of rock. Fracturing allows the discharge of fluid overpressure, and fluid flows along a hydraulic gradient towards a low pressure reservoir. Different mechanisms may cause the precipitation from the fluid, such as a fluid pressure drop, a variation of temperature at the low pressure reservoir, or a different rock type inducing different Eh-pH conditions. Such precipitates in fractures are called veins, which often display paleo-fluid overpressures in rocks. In this study, we present some results from Devonian clastic sedimentary rocks of the Eifel area. Results are compared with other sedimentary basins to highlight some general aspects.
    Description: conference
    Keywords: 551 ; VAE 812 ; VAE 140 ; Variszisch-herzynische Orogene {Geologie} ; Gesteinsdeformation {Strukturgeologie} ; Rheinisches Schiefergebirge 〈West〉 ; Unterdevon ; Quarzgang ; Hydraulische Rissbildung
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Holocene shield volcanoes (lava shields) are common in Iceland, but they are restricted in space and time. As regards space, most of the shield volcanoes in Iceland occur within two bands in the West and North Volcanic Zones. There are no shields in the East Volcanic Zone apart from the island of Surtsey. The shields are mostly at the margins of or outside the volcanic systems. As regards time, many Holocene shield volcanoes formed some 5000–10000 years ago during early postglacial time. Apart from the shield on top of the island of Surtsey, there are no known shields in Iceland younger than about 3500B.P....
    Description: conference
    Keywords: 551 ; VAD 700 ; VAD 300 ; Regionaler Vulkanismus {Geologie} ; Vulkanformen und Vulkantypen {Geologie} ; Island ; Holozän ; Schildvulkan
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2021-03-29
    Description: Halite veins hosted in clastic sedimentary rocks are frequently observed next to evaporite layers. Their microstructure can be enhanced by gamma irradiation and etching, which can be used to infer the deformation mechanism of halite (e.g. Howard & Kerr 1960, Schleder & Urai 2005). In this study, we present results from gammadecorated vein microstructures of fibrous halite veins hosted in claystone.
    Description: conference
    Keywords: 551 ; VAE 160 ; VKA 200 ; VAE 140 ; Salztektonik {Strukturgeologie} ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Steinsalz ; Mikrogefüge ; Deformation 〈Geologie〉 ; Salztektonik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2021-03-29
    Description: Archaische Granitoide und paläoproterozoische Metasedimente der Huronian Supergroup werden von dem schüsselförmigen und partiell erodierten 1.85 Ga alten Impaktschmelzkomplex der Sudbury-Impaktstruktur überlagert. Huronische Metasedimente und deren basaler Kontakt zum granitoiden Grundgebirge stehen in einer Entfernung bis zu 15km von dem lagigen Komplex und um diesen herum steil. Obwohl diese Steilstellung durch die Bildung eines impakt-induzierten Zentralberges erklärt werden kann, ist unklar, ob orogene Verformung vor dem Impakt an der Steilstellung beteiligt war. Um hierüber Aufschluss zu gewinnen, wurden die basalen Huronischen Einheiten, insbesondere die karbonatische Espanola Formation und deren benachbarte Metakonglomerate und Metasandsteine, nordöstlich des Impaktschmelzkomplexes strukturell untersucht. Aufgrund er Nähe der metasedimentären Einheiten zu dem 2,5km mächtigen Schmelzkomplex wurde daher auch dessen möglicher thermischer Einfluss auf die Metasedimente untersucht...
    Description: conference
    Keywords: 551 ; VKB 280 ; VKB 295 ; VAE 140 ; VEV 127 ; VKA 200 ; Impaktgesteine {Petrologie} ; Metamorphe Komplexe, Nordamerika {Petrologie} ; Gesteinsdeformation {Strukturgeologie} ; Ontario {Geologie} ; Gefügekunde der Gesteine ; Sudbury 〈Ontario. Region〉 ; Mehrfachringbassin ; Proterozoikum ; mpaktmetamorphes Gestein ; Karbonatgestein ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2021-03-29
    Description: The Precambrian basement of southern Madagascar was reworked at high-grade metamorphic conditions during the East African Orogen (EAO of Stern, 1994) that formed during assembly of Gondwana in late Neoproterozoic/early Paleozoic times. At the end of the EAO, Madagascar is generally thought to be sandwiched between southern India and eastern Africa. Constraints on its paleoposition are often inferred from similarities in structural features on now dispersed continental fragments, in particular high-strain zones. Major zones with (sub)vertical foliation planes can be traced over hundreds of kilometres in southern Madagascar and have been interpreted as major vertical ductile shear zones (e.g. Windley et al. 1994; Martelat, 1998). The NW–SE trending Ranotsara Zone (dashed rectangle in Fig. 1) is regarded as an intracrustal mega strike-slip shear zone with a sinistral sense of shear that formed at the end of the Proterozoic (e.g. Nicollet, 1990; de Wit et al., 2001). A large number of studies have used the Ranotsara Zone to propose Gondwana reconstructions. The Ranotsara Zone has been correlated with various ductile shear zones in southern India, e.g. with the Bhavani Shear Zone or the Moyar Shear Zone (Katz & Premoli, 1979), the Palghat-Cauvery Shear Zone (de Wit et al., 1995), the Karur-Kamban- Painavum-Trichur Shear Zone (de Wit et al., 2001; Ghosh et al. 2004) or with the Achankovil Shear Zone (Windley et al., 1994; Martelat, 1998). Within Madagascar, the Ranotsara Zone has been correlated along strike with the more N–S trending Bongolava Zone in central-western Madagascar (Hottin 1976), and the Bongolava- Ranotsara Zone has been further traced into the Surma Shear Zone (Windley et al. 1994) and its along-strike continuation, the Aswa Shear Zone in eastern Africa (Müller 2000). Chetty (2003) suggested that the Ranotsara Zone is not only a mega shear zone, but also a terrane boundary separating a region with Archean crust to the north from a region with Neoproterozoic crust to the south. Our remote sensing and field studies of southern Madagascar indicate that the Ranotsara Zone is neither a major terrane boundary nor an intracrustal mega strike-slip shear zone and therefore can not be used as a ‘piercing point’ in Gondwana reconstructions...
    Description: conference
    Keywords: 551 ; VAE 700 ; VAE 500 ; VAE 850 ; VEQ 300 ; VKB 294 ; Bau der Erdkruste großer Regionen der Erde {Geologie} ; Geotektonische Entwicklung der Erdkruste {Geologie} ; Festländische Lineamente {Geologie} ; Madagaskar {Geologie} ; Metamorphe Komplexe, Afrika {Petrologie} ; Madagaskar 〈Süd〉 ; Präkambrium ; Kristallin ; Scherzone ; Korrelation ; Gondwana
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2021-03-29
    Description: The multidetector texture diffractometer SKAT (from Russian: Spektrometer Kolitshestvennovo Analiza Tekstury) at the pulsed reactor IBR-2 in Dubna, Russia, started operation in March 1997 and is open for users from all countries. Application of time-of-flight (TOF) diffraction to texture measurements offers the opportunity to record complete diffraction patterns, i.e., to measure several pole figures simultaneously. To allow high spectral resolution for measurements on polyphase geological samples with many diffraction patterns, the instrument was placed at the end of an over 100m long flight path. In this paper, we will summarize advantages and disadvantages of the SKAT, as well as intended improvements.
    Description: conference
    Keywords: 551 ; VAE 120 ; VGA 440 ; VGB 900 ; VKA 200 ; Methodik {Strukturgeologie} ; Sonstige Methoden {Mineralogie: Kristallographie} ; Sonstige: Luminiszens etc. {Mineralogie} ; Gefügekunde der Gesteine ; Dubna ; SKAT ; Neutronendiffraktrometer ; Neutronendiffraktrometrie ; Texturanalyse
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2021-03-29
    Description: To understand seismogenesis in shallow parts of subduction zones, it is vital to know about strength and frictional parameters of subducted sediment. For this purpose, PETROTEC, as part of the TIPTEQ-Project, gathers geotechnical data for sediments deposited on the incoming Nazca Plate, the trench and the slope off the southern Chilean coast during the last 5 Ma, and whose equivalents are now being underthrusted into the seismogenic zone beneath South America. Material comes from gravity cores collected during R/V SONNE Cruises SO181 (Flüh E. & Grevemeyer I (Editors) 2005), SO102 (Hebbeln D, Wefer G, et al. 1995) and SO156 (Hebbeln D, et al. 2001), as well as from ODP Leg 141 (Behrmann JH, et al. 1992) drill cores. Sediment strength and frictional properties are determined by triaxial testing, ring shear testing and direct shear testing...
    Description: conference
    Keywords: 551 ; VAT 210 ; VBP 100 ; VBP 400 ; VAE 130 ; VKB 311 ; Untersuchungsverfahren mariner Sedimente {Geologie} ; Methodik, Untersuchungsverfahren und Instrumente {Ingenieurgeologie} ; Felsmechanik, Gebirgsmechanik, Gebirgsdruck ; Geomechanik ; Untersuchungsmethoden und Probennahme im Gelände {Sedimentologie} ; Chile ; Kontinentalrand ; Konturit ; Gesteinsmechanik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2021-03-29
    Description: Aus der Verteilung und Lage tertiärer und quartärer Ablagerungen in Mitteleuropa lassen sich tertiäre Paläooberflächen rekonstruieren. Die spätere Verstellung dieser Oberflächen erlaubt es, die vertikalen Krustenbewegungen der jüngeren und jüngsten geologischen Vergangenheit zu quantifizieren. Diese Hebungs- und Senkungsbewegungen sind nur wenig durch die lokale Heraushebung der mitteldeutschen Mittelgebirge beeinflusst. Sie sind vor allem die Folge sehr großräumiger Verstellungen der Erdkruste zwischen Nordsee und Fichtelgebirge, bei denen Prozesse im Erdmantel einen entscheidenden Einfluss im großräumigen (mitteleuropäischen) Maßstab haben.
    Description: conference
    Keywords: 551 ; VAG 130 ; VEB 210 ; VAE 400 ; VAE 120 ; VBF 000 ; Paläogeomorphologie {Geomorphologie} ; Deutschland {Geologie} ; Tektogenese {Geologie} ; Methodik {Strukturgeologie} ; Elektronische Datenverarbeitung in der Geologie ; Mitteldeutschland ; Tertiär ; Quartär ; Hebung 〈Geologie〉 ; Rezente Krustenbewegung ; Geoinformationssystem ; Fossile Erdoberfläche ; Rekonstruktion
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: When viewed as ideal elastic cracks, seismogenic faults are often modeled as decreases from the host rock to the boundary between the core and the damage zone. mode II or mode III cracks in semiinfinite elastic bodies or half spaces. These models normally assume the rock to be homogeneous and isotropic. Such assumptions may be justified and necessary when using closed-form analytical solutions for fault displacement. They are not justified, however, when we attempt to understand fault-displacement profiles along earthquake rupture sites or in paleofault studies. This follows because crustal segments hosting faults are, as a rule, not homogeneous and isotropic, but rather heterogeneous and anisotropic. In particular, the fault rocks commonly form layers or units parallel with the fault plane. Also, the mechanical properties of the rocks next to the fault change as the fault develops (Gudmundsson 2004). During repeated earthquakes in a seismogenic fault zone, two main rock units develop around the fault plane. One unit is the core, located next to the fault plane and normally composed of soft (low Young’s modulus) breccia, gouge, and other cataclastic rocks. The other unit is the damage zone, containing some cataclastic rocks but characterized by fractures of various types...
    Description: conference
    Keywords: 551 ; VAE 140 ; VAE 150 ; Gesteinsdeformation {Strukturgeologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Bruchzone ; Deformation 〈Geologie〉 ; Verwerfung ; Modellierung
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2021-03-29
    Description: Grain coarsening is a process that occurs in a wide variety of rock types. The application of grain growth theory to natural geologic materials has its beginnings in the theoretical foundations of the metallurgical and material sciences. Two types of grain growth can be statistically defined: 1) normal grain growth describing a uniform grain structure and 2) abnormal grain growth, where some grains grow more rapidly in size at the expense of matrix grains, thus creating a bimodal grain size distribution. This study aims to understand the grain coarsening phenomenon in metacarbonate rocks, to determine the mechanisms involved and to elucidate the role of fluids (e.g. hydrothermal alteration). Metacarbonate units exhibiting coarsely crystalline fabrics, representing abnormal grain growth, and hydrothermal alteration have been investigated from two major geologic formations of the Damara Orogen (Namibia)...
    Description: conference
    Keywords: 551 ; VKA 200 ; VKB 294 ; VKB 250 ; VAE 814 ; VER 200 ; Gefügekunde der Gesteine ; Metamorphe Komplexe, Afrika {Petrologie} ; Metasedimente {Petrologie} ; Präkambrische Orogene {Geologie} ; Namibia {Geologie} ; Damara Orogen ; Marmor ; Korngröße ; Gefügeumwandlung ; Hydrothermalprozess
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2021-03-29
    Description: Der Geitafell-Vulkan ist ein erloschener tertiärer Zentralvulkan (Stratovulkan) in Südost-Island. Aufgrund tiefer glazialer Erosion ist das Innere des Vulkans bis hinab zur erloschenen krustalen Magmakammer aufgeschlossen. Das bietet die einmalige Möglichkeit, die Infrastruktur und die tektonische Entwicklung eines typischen isländischen Zentralvulkans zu untersuchen. Der Geitafell-Vulkan besteht aus einer Abfolge von eruptiven Materialien unterschiedlicher mechanischer Eigenschaften wie zum Beispiel basaltische Laven, Hyaloklastite und saure Extrusiva. Im Kern des Vulkans ist der obere Teil einer erloschenen krustalen Magmakammer in Form mehrerer Gabbrokörper aufgeschlossen. Im direkten Kontakt mit der Magmakammer befindet sich ein sehr dichter Schwarm von Kegelgängen, die von der Magmakammer injiziert wurden, als der Geitafell-Vulkan von etwa 5 bis 6Ma aktiv war (Fridleifsson, 1983). Um unser Verständnis über die vulkanotektonische Entwicklung des Zentralvulkans zu verbessern, wurden im Geitafell-Gebiet mehr als 500 Gänge und Kegelgänge, 400 Mineralgänge und etwa 1100 Klüfte gemessen...
    Description: conference
    Keywords: 551 ; VAD 300 ; VAD 700 ; VEZ 130 ; Vulkanformen und Vulkantypen {Geologie} ; Regionaler Vulkanismus {Geologie} ; Inselgruppen {Atlantischer Ozean: Geologie} ; Island ; Stratovulkan
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2021-03-29
    Description: The Tamtsag Basin in NE Mongolia is part of a widespread basin system which formed during Late Jurassic and Cretaceous times (Graham et al. 2001, Qing-Ren et al. 2003). It is filled with continental sediments and volcanics which can reach up to 4 km in thickness. Rifting and subsequent basin inversion led to a complex basin geometry characterized by several horst and graben structures. The geodynamic causes for regional basin formation are discussed controversially and several hypothesis ranging from orogenic collaps via subduction rollback to collision-induced rifting have been put forward. Scientific research on the Mesozoic basins in Mongolia has so far concentrated on the East Gobi Basin to the south (Graham et al 2001, Prost 2004, Johnson 2004) and some work has also been published on the Hailar Basin (Qing-Ren et al. 2003), the northeastward continuation of the Tamtsag Basin into China. Fundamental data on the fill and tectonics of the Tamtsag Basin in between is still missing. This is partly due to poor exposure as most of the basin fill is covered by Cenozoic sediments and only locally, near the bordering faults, rocks are accessible for surface investigations. However, recent discoveries of oil in the Tamtsag and Hailar Basins have resulted in intense exploration activity and a strong interest in the area. This contribution describes the results of a field campaign in fall 2005 focusing on the basin fill while a companion paper (Davaa et al. this volume) deals with the basin structure and hydrocarbon potential of the Tamtsag Basin.
    Description: conference
    Keywords: 551 ; VAE 820 ; VEK 500 ; VAE 200 ; Sedimentationsbecken als Erdkrustentypen {Geologie} ; Mongolei (Mongolische Volksrepublik) {Geologie} ; Geodynamik der Lithosphäre {Geologie} ; Mongolei 〈Südost〉 ; Sedimentationsbecken ; Geodynamik
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...