ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Articles  (3,088)
  • American Geophysical Union  (1,922)
  • Wiley  (1,166)
  • American Association for the Advancement of Science (AAAS)
  • American Meteorological Society
  • American Physical Society (APS)
  • Public Library of Science
  • Springer
  • Springer Nature
  • 2010-2014  (2,522)
  • 2000-2004  (566)
  • 1985-1989
  • 1980-1984
  • 1960-1964
  • 1955-1959
  • 1935-1939
  • 1930-1934
  • Geochemistry Geophysics Geosystems (G3)  (1,166)
  • 6521
  • Geosciences  (3,088)
  • Information Science and Librarianship
  • Philosophy
  • Natural Sciences in General
Collection
  • Articles  (3,088)
Source
Publisher
  • American Geophysical Union  (1,922)
  • Wiley  (1,166)
  • American Association for the Advancement of Science (AAAS)
  • American Meteorological Society
  • American Physical Society (APS)
    • +
Years
Year
Journal
Topic
  • 1
    facet.materialart.
    Unknown
    Velocity structure beneath the Southern Puna Plateau: Evidence for delamination (2013)
    Wiley
    Details
    Publication Date: 2013-09-08
    Description: The high elevation of the Southern Puna Plateau, the widespread melting of its crust, the gap in intermediate depth seismicity and the recent eruptions of ignimbrite complexes can be explained by delamination of the lithospheric mantle beneath it. To test this hypothesis, an array consisting of 73 broad band and short period seismic stations was deployed in the region for a period of two years starting in 2007. We inverted the data using the two plane wave approach and obtained 1D and 3D Rayleigh wave phase velocities. Our dispersion curve shows that at short periods (〈70 s) the phase velocities are slightly higher than those of the Tibetan plateau and lower than those of the Anatolian plateau. At periods of 100-140 s we observe a low velocity zone that might be remnant hot asthenosphere below a flat slab (7-10 Ma). We estimate the average continental lithosphere thickness for the region to be between 100 and 130 km. Our three dimensional Rayleigh wave phase velocities show a high velocity anomaly at low frequencies (0.007, 0.008 and 0.009 Hz) slightly to the north of Cerro Galan. This would be consistent with the hypothesis of delamination in which a piece of lithosphere has detached and caused upwelling of hot asthenosphere which in turn caused widespread alkaline-collision related volcanism. This interpretation is also corroborated by our shear wave velocity model where a high velocity anomaly beneath the northern edge of Cerro Galan at 130 km depth is interpreted as the delaminated block on top of the subducting Nazca slab.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Chlorine Isotope constraints on fluid-rock interactions during subduction and exhumation of the Zermatt-Saas Ophiolite (2013)
    Wiley
    Details
    Publication Date: 2013-09-21
    Description: Chlorine isotope compositions of high-pressure (~2.3 GPa) serpentinite, rodingite, and hydrothermally altered oceanic crust (AOC) differ significantly from high- and ultrahigh-pressure (〉3.2 GPa) metasedimentary rocks in the Aosta region, Italy. Texturally early serpentinites, rodingites, and AOC have bulk δ 37 Cl values indistinguishable from those of modern seafloor analogues (δ 37 Cl = -1.0 to +1.0‰). In contrast, serpentinites and AOC samples that recrystallized during exhumation have low δ 37 Cl values (-2.7 to -0.5‰); 37 Cl depletion correlates with progressive changes in bulk chemistry. HP/UHP metasediments have low δ 37 Cl values (median = -2.5‰) that differ statistically from modern marine sediments (median = -0.6‰). Cl in metasedimentary rocks is concentrated in texturally early minerals, indicating modification of seafloor compositions early in the subduction history. The data constrain fluid sources during both subduction- and exhumation-related phases of fluid-rock interaction: (1) Marine sediments at the top of the downgoing plate likely interacted with isotopically light pore fluids from the accretionary wedge in the early stages of subduction. (2) No pervasive interaction with externally derived fluid occurred during subsequent subduction to the maximum depths of burial. (3) Localized mixing between serpentinites and fluids released by previously isotopically modified metasediments occurred during exhumation in the subduction channel. Most samples, however, preserved protolith signatures during subduction to near-arc depths.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Lithological structure of the Galápagos plume (2013)
    Wiley
    Details
    Publication Date: 2013-09-21
    Description: We have measured Ni, Ca, and Mn in olivine phenocrysts from volcanoes in the Galápagos Archipelago to infer the mantle source lithologies. Results show that peridotite is the dominant source lithology for Fernandina, Floreana, Genovesa, Wolf Island, and Darwin Island. These volcanoes largely characterize the PLUME, WD, FLO and DUM Nd, Sr, and Pb isotopic endmembers of Harpp and White (2001). Volcan Wolf, Alcedo, Marchena, and Cerro Azul, also produced from the melting of peridotite sources, have isotopic compositions that can be defined by mixing of the 4 isotopic endmembers. Our analysis suggests that peridotite was present in the sources of the volcanoes covered in this study and therefore is the dominant source lithology of the Galápagos plume. Pyroxenite melting is generally focused in two isotopically distinct domains: Roca Redonda, Volcan Ecuador, and Sierra Negra in the enriched western part of the archipelago, and Santiago, Santa Cruz, and Santa Fe in the depleted east. One implication of this finding is that the Western and Eastern Pyroxenite Domains represent two separate bodies of recycled crust within the Galápagos mantle plume. Furthermore, both isotopically enriched and depleted domains of the archipelago were generated from mixtures of peridotite and pyroxenite. This suggests that there is no relationship between the source lithology of the Galápagos plume and its isotopic characteristics. The identification of peridotite source melting in volcanoes with isotopic characteristics that have been attributed to recycled crust points to the importance of mixing in OIB genesis, consistent with studies in the Canary Islands.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    The influence of high latitude flux lobes on the Holocene paleomagnetic record of IODP Site U1305 and the northern North Atlantic (2013)
    Wiley
    Details
    Publication Date: 2013-09-25
    Description: Paleomagnetic analysis and radiocarbon dating of an expanded Holocene deep-sea sediment sequence recovered by Integrated Ocean Drilling Program (IODP) Expedition 303 from Labrador Sea Site U1305 (Lat: 57°28.5 N, Long. 48°31.8 W, water depth 3459 m) provides insights into mechanisms that drive both paleomagnetic secular variation (PSV) and magnetization acquisition in deep-sea sediments. Seventeen radiocarbon dates on planktonic foraminifera define postglacial (c. 8 ka) sedimentation rates as ranging from 35 to 〉 90 cm/kyr. Alternating field (AF) demagnetization of u-channel samples show that these homogeneous sediments preserve a strong, stable, and consistently well-defined component magnetization. Normalized remanence records pass reliability criteria for relative paleointensity (RPI) estimates. Assuming that the age of magnetization is most accurately defined by well dated PSV records with the highest sedimentation rates, allows us to estimate and correct for temporal offsets at Site U1305 interpreted to result from post-depositional remanence acquisition at a depth of ~ 20 cm. Comparisons indicate that the northern North Atlantic PSV and RPI records are more consistent with European than North American records, and the evolution of virtual geomagnetic poles (VGP) are temporally and longitudinally similar to global reconstructions, though with much larger latitudinal variation. The largest deviations from a geocentric axial dipole (GAD) are observed during times of the highest intensities, in contrast to the usual assumption. These observations are consistent with the idea that PSV in the North Atlantic and elsewhere during the Holocene results from temporal oscillations of high latitude flux concentrations at a few recurrent locations.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Interrelation between rifting, faulting, sedimentation, and mantle serpentinization during continental margin formation - including examples from the Norwegian Sea (2013)
    Wiley
    Details
    Publication Date: 2013-09-12
    Description: The conditions permitting mantle serpentinization during continental rifting are explored within 2D thermotectonostratigraphic basin models, which track the rheological evolution of the continental crust, account for sediment blanketing effects, and allow for kinetically controlled mantle serpentinization processes. The basic idea is that the entire extending continental crust has to be brittle for crustal scale faulting and mantle serpentinization to occur [ Perez-Gussinye and Reston , 2001]. The isostatic and latent heat effects of the reaction are fully coupled to the structural and thermal solutions. A systematic parameter study shows that a critical stretching factor exists for which complete crustal embrittlement and serpentinization occurs. Increased sedimentation rates shift this critical stretching factor to higher values as sediment blanketing effects result in higher crustal temperatures. Sediment supply has therefore, through the temperature-dependence of the viscous flow laws, strong control on crustal strength and mantle serpentinization reactions are only likely when sedimentation rates are low and stretching factors high. In a case study for the Norwegian margin we test whether the inner lower crustal bodies (LCB) imaged beneath the Møre and Vøring margin could be serpentinized mantle. Multiple 2D transects have been reconstructed through the 3D data set by Scheck-Wenderoth and Maystrenko [2011]. We find that serpentinization reactions are possible and likely during the Jurassic rift phase. Predicted thicknesses and locations of partially serpentinized mantle rocks fit to information on LCBs from seismic and gravity data. We conclude that some of the inner LCBs beneath the Norwegian margin may be partially serpentinized mantle.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Anomalously thin transition zone and apparently isotropic upper mantle beneath Bermuda: Evidence for upwelling (2013)
    Wiley
    Details
    Publication Date: 2013-10-03
    Description: The origin of the Bermuda swell and volcanism remains enigmatic. The lack of an associated time-progressive hotspot track and absence of present-day volcanic activity make it difficult to reconcile with a deep mantle plume model. We analyze shear wave splitting measurements to estimate mantle flow direction and receiver function stacks to place constraints on the mantle transition zone thermal structure. *KS phases exhibit well-resolved null arrivals (no splitting) beneath the swell over a range of back azimuths. We find that the 410 and 660 km discontinuities are 49 ± 5 km and 19 ± 5 km deeper than the global average, respectively, leading to a transition zone thickness that is 27 ± 4 km thinner than average. Together, an apparently isotropic upper mantle and a thinned mantle transition zone suggest that mantle flow is primarily vertical beneath the swell, consistent with the presence of hot, buoyant mantle at depth.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    The active portion of the Campi Flegrei caldera structure imaged by 3D inversion of gravity data (2013)
    Wiley
    Details
    Publication Date: 2013-10-04
    Description: We present an improved density model and a new structural map of the Neapolitan Yellow Tuff caldera, the active portion of the nested Campi Flegrei caldera. The model was built using a new 3D inversion of the available high-precision gravity data, and a new digital terrain and marine model. The inversion procedure, based on a variable-depth lumped assembling of the subsurface gravity distribution via cell aggregation, gives better defined insights into the internal caldera architecture, that well agree with the available geological, geophysical and geochemical data. The adopted 3D gravity method is highly efficient for characterizing the shallow caldera structure (down to 3 km depth) and defining features related to regional or volcano tectonic lineaments and dynamics. In particular, the resulting density distribution highlights a pronounced density low in correspondence of the central portion of the caldera with a detail not available till now. The joint interpretation of the available data, suggests a subsurface structural setting that supports a piecemeal collapse of the caldera, and allows the identification of its headwall. Positive gravity anomalies localize dense intrusions (presently covered by late volcanic deposits) along the caldera marginal faults, and the main structural lineaments both bordering the resurgent block and cutting the caldera floor. These results allow us to both refine the current geological-structural framework and propose a new structural map that highlights the caldera boundary and its internal setting. This map is useful to interpret the phenomena occurring during unrest, and to improve both short- and long-term volcanic hazards assessment.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Geophysical modeling of collapse-prone zones at Rumble III seamount, southern Pacific ocean, New Zealand (2013)
    Wiley
    Details
    Publication Date: 2013-10-04
    Description: Catastrophic collapses of submarine volcanoes have the potential to generate major tsunami, threatening many coastal populations. Recognizing the difficulties surrounding anticipations of these events, quantitative assessment of collapse-prone regions based on detailed morphological, geological and geophysical mapping can still provide important information about the hazards associated with these collapses. Rumble III is one of the shallowest, and largest, submarine volcanoes found along the Kermadec arc, and is both volcanically and hydrothermally active. Previous surveys have delineated major collapse features at Rumble III; based on time-lapse bathymetry, dramatic changes in the volcano morphology have been shown to have occurred over the interval 2007 to 2009. Furthermore, this volcano is located just ˜300 km from the east coast of the North Island of New Zealand. Here, we present a geophysical model for Rumble III, that provides the locations and sizes of potential weak regions of this volcano. Shipborne and near-seafloor geological and geophysical data collected by the AUV Sentry are used to determine the subsurface distribution of weak and unstable volcanic rocks. The resulting model provides evidence for potentially unstable areas located in the Southeastern flank of this volcano which should be included in future hazard predictions.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Tibetan and Indian lithospheres in the upper mantle beneath Tibet: Evidence from broadband surface-wave dispersion (2013)
    Wiley
    Details
    Publication Date: 2013-10-04
    Description: Broadband seismic experiments over the last two decades have produced dense data coverage across Tibet. Yet, the mechanism of the India-Asia lithospheric convergence beneath it remains a puzzle, with even its basic features debated and with very different end-member models advocated today. We measured highly accurate Rayleigh- and Love-wave phase-velocity curves in broad period ranges (up to 5-200 s) for a few tens of pairs and groups of stations across Tibet, combining, in each case, hundreds to thousands of inter-station measurements made with cross-correlation and waveform-inversion methods. Robust shear-velocity profiles were then determined by extensive series of non-linear inversions of the data, designed to constrain the depth-dependent ranges of isotropic-average shear speeds and radial anisotropy. Temperature anomalies in the upper mantle were estimated from shear velocities using accurate petro-physical relationships. Our results reveal strong heterogeneity in the upper mantle beneath Tibet. Very large high-velocity anomalies in the upper mantle are consistent with the presence of underthrust (beneath southwestern Tibet) and subducted (beneath central and eastern Tibet) Indian lithosphere. The lithosphere. In contrast to the Indian lithosphere, Tibetan lithosphere and asthenosphere display low to normal shear speeds; Tibetan lithosphere is thus warm and thin. Radial anisotropy in the upper mantle is weak in central and strong in northeastern Tibet, possibly reflecting asthenospheric flow above the subducting Indian lithospheric slab.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Distinctive upper mantle anisotropy beneath the High Lava Plains and Eastern Snake River Plain, Pacific Northwest, USA (2013)
    Wiley
    Details
    Publication Date: 2013-10-04
    Description: The Pacific Northwest (PNW) has experienced voluminous intraplate volcanism over the past ~17 Ma, beginning with the Steens/Columbia River flood basalts and continuing with the still-ongoing volcanism in the High Lava Plains (HLP) and eastern Snake River Plain (SRP). Here we present two complementary datasets (SKS splitting and Rayleigh wave phase velocity anisotropy) that place constraints on the anisotropic structure of the upper mantle beneath the HLP and SRP regions. Beneath the HLP, SKS phases reveal dominantly E-W fast splitting directions and large (up to ~2.7 sec) delay times, with pronounced lateral variations in δ t . Lateral and depth variability in the strength of anisotropy beneath the HLP is also evident from Rayleigh wave dispersion. Beneath the SRP, SKS splitting delay times are much smaller (~0.5 sec) and surface wave observations suggest a region of upper mantle anisotropy (~50-150 km depth) with a geometry that deviates significantly from the generally plate motion parallel fast directions observed just outside of the SRP. Beneath the HLP, the geometry of the anomalously strong anisotropy is similar to the anisotropy in the deeper parts of the upper mantle, resulting in constructive interference and large SKS splitting delay times. Beneath the SRP, the geometry of the anomalous anisotropic region in the shallow mantle is different, resulting in destructive interference and reduced SKS splitting delay times. We discuss several possible explanations for these observations, including variations in olivine lattice preferred orientation (LPO) strength, transitions in olivine fabric type, and a contribution from aligned partial melt.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...