ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Collection
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 303 (1983), S. 205-209 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Isotope geochemistry of Cenozoic volcanic rocks from the western USA demonstrates considerable mantle heterogeneity in the source regions. The Basin and Range volcanic rocks have tapped a source similar to mid-oceanic ridge basalts and the Hawaiian islands, while the magmas erupted in the Sierran ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0819
    Keywords: Continental flood basalts ; Rhyolites ; Chemical stratigraphy ; Magma types ; Boreholes ; Paraná ; continental break-up
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A new classification scheme has been developed to assign the lava flows of the Paraná continental flood basalt province (South America) into geochemically distinct magma types, with six basaltic major and trace element abundances and/or ratios. By mapping out the spatial distribution of these magma types within the lava sequences, it has been possible to determine the internal stratigraphy of the lava pile on a regional scale. Previous studies on road profiles traversing the well-exposed coastal Serra Geral escarpment of southern Brazil are summarised together with results from some new sampled sections. More widespread stratigraphical investigations of the Paraná lavas have been hampered by the lack of sufficient topographic relief and the cover of sedimentary rocks. However, access to drill-core chippings from nine boreholes in the central Paraná region has provided a unique opportunity to investigate the stratigraphy of the otherwise inaccessible deeper levels of the lava pile and to map out stratigraphic variations in three dimensions. The borehole samples have indicated cated a stacking of units of different magma types all overlapping towards the north, which suggests that the main locus of magmatism moved northwards with time within the Paraná basin. This migration could be related to the northward propagation of rifting during the initiation of the South Atlantic Ocean. Maps of the surface distribution of samples of each magma type show a pattern consistent with the stratigraphy inferred from the boreholes, although suggesting that the shift in magmatism may have been towards the northwest. On the basis of geochemical similarities between magma types and their inferred stratigraphical relationships, it is proposed that the Paraná can be divided into two principal magmatic centres: (1) an older one in the south, comprising the Gramado, Esmeralda and Urubici magma types; and (2) a younger one, developed about 750 km to the north, formed by the Pitanga, Paranapanema and Ribeira magma types.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 303 (1983), S. 205-209 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Isotope geochemistry of Cenozoic volcanic rocks from the western USA demonstrates considerable mantle heterogeneity in the source regions. The Basin and Range volcanic rocks have tapped a source similar to mid-oceanic ridge basalts and the Hawaiian islands, while the magmas erupted in the Sierran ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The technique of single zircon dating from the thermal evaporation of 207Pb/206Pb (Kober 1986, 1987) provides a means of dating successive periods of growth and nucleation of zircons in polymetamorphic assemblages. In contrast Nd model ages may provide a measure of the period of crustal residency for the sample or its protolith. These two techniques have been combined to elucidate the tectonic history of the Proterozoic mobile belt of southern India, exposed south of the Palghat-Cauvery Shear Zone that marks the southern boundary of the Archaean craton of Karnataka. The two main tectonic units of this mobile belt comprise the Madurai and Trivandrum Blocks, both of which are characterised by massive charnockite uplands and low-lying polymetamorphic metasedimentary belts that have undergone a complex tectonic history throughout the Proterozoic. Evidence for early Palaeoproterozoic magmatism is restricted to the Madurai Block where single zircon evaporation ages from a metagranite (2436 ± 4 Ma) are similar to model Nd ages from a range of lithologies suggesting crustal growth at that time. The Trivandrum Block, to the south of the Achankovil shear zone, is comprised of the Kerala Khondalite Belt, the Nagercoil charnockites and the Achankovil metasediments. Single zircon evaporation ages, together with conventional zircon and garnet chronometry, suggest that all three units underwent upper-amphibolite facies metamorphism at ∼1800 Ma, an event unrecorded in the metagranite from the Madurai Block. This implies that the Madurai and Trivandrum blocks represent distinct terrains throughout the Palaeoproterozoic. Model Nd ages from the Achankovil metasediments are much younger (1500–1200 Ma) than those from the adjacent Kerala Khondalite Belt and Madurai Blocks (3000–2100 Ma), but there is no evidence for zircon growth in these metasediments during the Mesoproterozoic. Hence the comparatively young model Nd ages of the metasediments are indicative of a mixed provenance rather than a discrete period of crustal growth. Zircon overgrowths from the Madurai Block (547 ± 17 Ma) and Achankovil metasediments (530 ± 21 Ma) suggest that all tectonic units of the Proterozoic mobile belt of South India shared the same metamorphic history from the early Palaeozoic. This event has been recognised in the basement lithologies of Sri Lanka and East Antarctica, confirming that the constituent terrains of East Gondwana had assembled by this time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Precambrian Research 236 (2013): 31–45, doi:10.1016/j.precamres.2013.07.006.
    Description: The reconstruction of the palaeogeography and supercontinent amalgamation processes in the Precambrian is generally guided by the age of magmatic and metamorphic rocks in orogenic belts, which formed along the sutures of colliding continents or smaller terranes (e.g., Wareham et al., 1998; Dalziel et al., 2000). Yet, the investigation and interpretation of these belts becomes increasingly difficult with increasing age of the orogenic cycles, due to metamorphic overprint, fragmentation by subsequent rifting processes, erosive loss, and covering by younger deposits or by ice. An alternative and important recorder of geodynamic processes are clastic sediments that are fed from the eroding orogenic belts and are deposited on stable cratonic platforms, where they may escape erosion and high-grade metamorphism for billions of years. These clastic sediment deposits generally contain abundant detrital zircon, which provides an age record of the eroded orogenic belts, reflecting a large number of rock types. The age spectra of detrital zircon recovered from sedimentary basins can be used to distinguish between different tectonic settings in which the sediments were deposited, such as convergent margins, collisional orogens or extensional settings (von Eynatten & Dunkl, 2012; Cawood et al., 2012). The supercontinent Rodinia formed by convergence and collision of all the major landmasses between 1200 and 950Ma, i.e. in the late Mesoproterozoic (Hoffman, 1991; Li et al., 2008). Key evidence for the collisions is found in the late Mesoproterozoic orogenic belts, which span thousands of kilometres through North and South America, southern Africa, Australia, Asia and East Antarctica. Yet, the paleogeographic reconstruction of Rodinia is still uncertain, and at least three different configurations have been discussed (Li et al., 2008). Issues arise in part from the uncertainties in terrane boundaries within East Antarctica and possible connections to the African Kalahari Craton. At least one major late Mesoproterozoic (Stenian) suture must be located in Dronning Maud Land (DML; East Antarctica), but its location and the extent of possible crustal blocks are still enigmatic (Jacobs et al., 2008a).
    Description: This study was financially supported by the NERC Antarctic Funding Initiative (grant NE/D008689/1 to CJH), a NERC analytical grant (grant IMF364/1008 to CJH/HRM) and the NSF polar program (AES grant 1142156 to HRM).
    Keywords: Detrital zircon ; Geochronology ; Dronning Maud Land ; Rodinia ; Mesoproterozoic
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Hawkesworth, Chris J; Elderfield, Henry (1978): The strontium isotopic composition of interstitial waters from sites 245 and 336 of the Deep Sea Drilling Project. Earth and Planetary Science Letters, 40(3), 423-432, https://doi.org/10.1016/0012-821X(78)90165-6
    Publication Date: 2023-06-27
    Description: Measurements of 87Sr/86Sr ratios of interstitial waters from leg 25, site 245 and leg 38, site 336 of the Deep Sea Drilling Project show that the enrichment of Sr[2+] with depth is caused both by the alteration of volcanic material and by the introduction of strontium derived from calcium carbonate. 87Sr/86 Sr ratios range from 0.70913 to 0.70794 at site 245 and from 0.70916 to 0.70694 at site 336. The low ratios compared with contemporaneous seawater reflect the release of Sr from a volcanic source having, according to material-balance calculations, a 87Sr/86 Sr ratio of about 0.7034 at site 336. At this site the source appears to be volcanic ash and not basaltic basement which acts as a sink for Sr[2+] during in situ low-temperature weathering. The volcanic contribution to the strontium enrichment in the basal interstitial waters varies from 〈10% at site 245 to 〉50% at site 336. The remaining Sr[2+] is derived from Sr-rich biogenic carbonate during diagenetic recrystallization to form Sr-poor calcite.
    Keywords: 25-245_Site; 38-336; COMPCORE; Composite Core; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Indian Ocean//BASIN; Leg25; Leg38; North Atlantic/Norwegian Sea
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2023-06-27
    Keywords: 91-595A; Beryllium; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Inductively coupled plasma - mass spectrometry (ICP-MS); Leg91; Lithium; Lithium/Beryllium ratio; Lithologic unit/sequence; Sample code/label; South Pacific; Thorium; Thorium/Beryllium ratio
    Type: Dataset
    Format: text/tab-separated-values, 63 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2023-06-27
    Keywords: 91-596_Site; Beryllium; COMPCORE; Composite Core; Deep Sea Drilling Project; DEPTH, sediment/rock; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Inductively coupled plasma - mass spectrometry (ICP-MS); Leg91; Lithium; Lithium/Beryllium ratio; Lithologic unit/sequence; Sample code/label; South Pacific; Thorium; Thorium/Beryllium ratio
    Type: Dataset
    Format: text/tab-separated-values, 77 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2023-06-27
    Keywords: 21-204; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Lead-206/Lead-204 ratio; Lead-207/Lead-204 ratio; Lead-208/Lead-204 ratio; Leg21; Mass spectrometer Finnigan MAT 261; Neodymium-143/Neodymium-144 ratio; Sample code/label; South Pacific/TRENCH; Strontium-87/Strontium-86 ratio
    Type: Dataset
    Format: text/tab-separated-values, 84 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2023-06-27
    Keywords: 25-245_Site; COMPCORE; Composite Core; Deep Sea Drilling Project; DEPTH, sediment/rock; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Indian Ocean//BASIN; Isotope ratio mass spectrometry; Leg25; Sample code/label; Strontium/Chloride ratio; Strontium-87/Strontium-86 ratio; Strontium-87/Strontium-86 ratio, error
    Type: Dataset
    Format: text/tab-separated-values, 31 data points
    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...