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
  • 1
    Electronic Resource
    Electronic Resource
    Evidence for life on Earth before 3,800 million years ago (1996)
    [s.l.] : Nature Publishing Group
    Nature 384 (1996), S. 55-59 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] FIG. 1 a, Field exposure of the 3,850-yr-old Akilia island BIF3 (collected 150km south of Isua, 63° 55'40" N, 51° 41'30" W; photograph by A. Nutman) in southern West Greenland. Finely alter-nating bands of magnetite (dark) and silicates (light) are evident on the broken-off boulder which ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/384055a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Charnockite and granite formation and influx of CO 2 at Kabbaldurga (1981)
    [s.l.] : Nature Publishing Group
    Nature 294 (1981), S. 550-552 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] During recent field work in the Archaean ( 2,700 Myr) gneiss terrain between Mysore and Bangalore, Karnataka, south India, the southern end of the Closepet Granite7 including the area of Kabbaldurga was examined. This granite is a substantial body with a linear extension northwards for some 200 km ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/294550a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Late Archaean terrane accretion in the Godthåb region, southern West Greenland (1988)
    [s.l.] : Nature Publishing Group
    Nature 335 (1988), S. 535-538 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The field geology of the Nuuk region8,9 has been substantiated by much isotopic data10"15. This work distinguished a poly-genetic older complex dominated by the early Archaean Amitsoq gneisses, the Malene supracrustal rocks and a younger, polygenetic intrusive complex of quartzo-feldspathic ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/335535a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Crust formation in the Lewisian (1995)
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 366-366 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Burton et al1 have presented U-Pb and Sm-Nd mineral regression ages on rocks from the Lewisian complex at Gruinard Bay, which apparently require that "the history of crustal development in the Lewisian complex will have to be radically rethought"2. They1 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/375366a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    U-Pb isotopic evidence for the accretion of different crustal blocks to form the Lewisian Complex of northwest Scotland (1997)
    Springer
    Contributions to mineralogy and petrology 129 (1997), S. 326-340 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Single zircon and titanite U-Pb SHRIMP data presented for tonalite-trondhjemite-granodiorite (TTG) suite gneisses and an ultramafic rock from the northern and central regions of the Lewisian Complex of northwest Scotland, show that protolith ages of tonalitic gneisses in the northern region (2800–2840 Ma) are significantly younger than those in the central region (2960–3030 Ma). Further evidence of a major (2490–2480 Ma) metamorphic event in the central region is documented by a metamorphic zircon associated with a granulite facies ultramafic body. A dioritic gneiss from the northern region has also been dated at c. 2680 Ma. The northern region therefore does not comprise reworked central region rocks and consequently the old models for the evolution of the Lewisian which were based upon this concept need replacing. It is instead proposed that two distinct crustal blocks, now the northern and central regions, were tectonically juxtaposed along a boundary corresponding to the Laxford Front. Juxtaposition would appear to have occurred in Proterozoic times, as it must have postdated the 2490–2480 Ma (?Inverian) metamorphism recorded only in the central region, and the emplacement of granite sheets restricted to the northern side of the boundary. The first recorded event common to both regions is resetting of titanite ages associated with c. 1750 Ma Laxfordian amphibolite facies metamorphism. Zircon inheritance in rocks of both regions is scarce. Within one zircon from the northern region a c. 3550 Ma core was found. This represents the oldest known material from the region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050340
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    U-Pb zircon geochronological evidence for Neoproterozoic events in the Glenfinnan Group (Moine Supergroup): the formation of the Ardgour granite gneiss, north-west Scotland (1997)
    Springer
    Contributions to mineralogy and petrology 128 (1997), S. 101-113 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The age and Precambrian history of the Moine Supergroup within the Caledonide belt of north-west Scotland have long been contentious issues. The Ardgour granite gneiss is essentially an in situ anatectic granite formed during deformation and regional high-grade metamorphism from Moine metasediments. High-precision TIMS and SHRIMP U-Pb zircon dating shows that the age of the anatectic Ardgour granite gneiss and its enclosed segregation pegmatites is 873 ± 7 Ma. This demonstrates the reality of a Neoproterozoic episode of high-grade metamorphism in the Glenfinnan Group Moine and, contrary to previous evidence, the absence of Grenvillian-aged metamorphism. This conclusion places constraints on Neoproterozoic palaeogeographic reconstructions of the North Atlantic region, indicating that the Moine rocks cannot be used as a link between the Grenvillian belt of North America and the Sveconorwegian orogen in Scandinavia. SHRIMP ages of between c. 1100 and 1900 Ma were obtained from detrital, inherited zircons and reflect the provenance of the Glenfinnan Group Moine sediments which must, therefore, have been deposited between c. 1100 and 870 Ma. Potential sources are found as relatively minor, tectonically bounded basement inliers within the British Caledonides, although more widespread source areas occur outside Britain in both Laurentia and Baltica. The most important feature of the provenance is the absence of detrital Archaean grains. This suggests that the Archaean Lewisian gneiss complex, which forms the basement component of the western foreland to the Caledonides in Britain, was not a major contributor to the Glenfinnan Group basin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050297
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Response of zircon U−Pb isotopes and whole-rock geochemistry to CO2 fluid-induced granulite-facies metamorphism, Kabbaldurga, Karnataka, South India (1992)
    Springer
    Contributions to mineralogy and petrology 111 (1992), S. 299-310 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The arrested, prograde amphibolite- to granulite-facies transition at Kabbaldurga, south India, overprints Archacan amphibolite-facies nebulitic gneisses and the late Archaean Closepet granite. Previous studies have shown that this facies transition was controlled by a channelled influx of a dehydrating fluid, assumed to be CO2, at ∼750°C and 5.5 kbar confining pressure. The effect of this type of prograde transition on zircon U−Pb isotopic systematics and whole-rock geochemistry has been studied using ∼1 kg amphibolite-facies, transitional and granulite-facies domains from a single block of gneiss. The zircon populations from all three domains have essentially similar morphology and U−Pb systematics. This similarity shows that at the conditions under which the prograde granulite-facies transition took place via fluid influx, the zircon U−Pb systematics were not disturbed by the process. Using the pooled data from all three domains, it is concluded that the protolith of the gneiss formed at 2965±4 Ma (2σ), and that zircons also grew during an anatectic event common to all domains at 2528±5 Ma. The granulite-facies metamorphism has not been dated directly due to the lack of response to the zircon U−Pb isotopic systematies to it. However, field and petrographic criteria dictate that its maximum age is 2528±5 Ma, the age of the anatectic event common to each domain in the gneiss block, which was overprinted during the granulite-facies event. For most major and trace elements, consistent enrichment or depletion trends associated with the transition to granulite facies cannot be identified with confidence. However, the granulite-facies portion is LREE (light-rare-earth-element)-enriched and H (heavy) REE-depleted compared with the amphibolite-facies domain, and the transitional domain is at intermediate values. The isotopic and geochemical evidence presented supports the conclusion that the granulite-facies charnockitic rocks at Kabbaldurga were not formed by removal of an anatectic melt, but that they formed later by simple metamorphic overprint of amphibolite-facies rocks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00311193
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    facet.materialart.
    Unknown
    The Laxford Shear Zone: an end-Archaean terrane boundary? (2010)
    In:  Geological Society Special Publication 335: 103-120.
    Details
    Publication Date: 2010-06-21
    Description: The Lewisian Gneiss Complex of northwestern Scotland consists of Archaean gneisses, variably reworked during the Proterozoic. It can be divided into three districts - a central granulite-facies district between districts of amphibolite-facies gneiss to the north and south. Recent work has interpreted these districts in terms of separate terranes, initiating a controversy that has implications for how Precambrian rocks are understood worldwide. The northern district of the Lewisian Gneiss Complex (the Rhiconich terrane) is separated from the central district (the Assynt terrane) by a broad ductile shear zone known as the Laxford Shear Zone. This paper reviews the geology of the Laxford Shear Zone, clarifying field relationships and discussing other evidence, to consider whether or not it does indeed represent a terrane boundary. A detailed review of field, geochemical and geochronological evidence supports the recognition of the separate Assynt and Rhiconich terranes. Mafic dykes (the Scourie Dyke Swarm) and granitoids, of Palaeoproterozoic age, occur on both sides of the Laxford Shear Zone and thus the terranes were most probably juxtaposed during the late Archaean to early Palaeoproterozoic Inverian event. Subsequently, the less-competent, more-hydrous amphibolite-facies gneisses of the Rhiconich terrane were affected by later Palaeoproterozoic (Laxfordian) deformation and partial melting, to a greater extent than the more-competent granulite-facies gneisses of the Assynt terrane.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER
  • 9
    facet.materialart.
    Unknown
    The emergence of the Eoarchaean proto-arc: evolution of a c. 3700 Ma convergent plate boundary at Isua, southern West Greenland (2013)
    Geological Society (of London)
    Details
    Publication Date: 2013-09-11
    Description: Eoarchaean juvenile crust formed as ‘proto-arcs’. The northern side of the Isua supracrustal belt is an archetypal proto-arc, with ≥3720 Ma boninites, c. 3720 Ma basalts and gabbros, 3720–3710 Ma andesites, diorites and mafic tonalites, 3710–3700 Ma intermediate-felsic volcanic and sedimentary rocks and 3700–3690 Ma chemical sedimentary rocks. On its northern side there is an extensive body of 3700–3690 Ma tonalite. During its evolution, the c. 3700 Ma Isua volcanic–sedimentary assemblage was partitioned into tectonic slices, with intercalation of mantle dunites with pillow basalts, prior to intrusion of c. 3710 Ma quartz diorites. Partitioning also occurred at 3690–3660 Ma, when the 30–20 million years life of the c. 3700 Ma Isua proto-arc was terminated by juxtaposition with the c. 3800 Ma terrane that occurs along the south of the Isua supracrustal belt. The trace element chemistry for all the ≥3720–3700 Ma mafic to intermediate volcanic rocks indicates fluid-fluxing mantle melting. The c. 3690 Ma tonalites have signatures showing melting of garnet-bearing mafic (eclogite) sources. The Isua c. 3700 Ma assemblage developed at an intra-oceanic convergent plate boundary, and it has a life-cycle broadly analogous to (but not identical to) an oceanic island arc eventually accreted against older crust.
    Print ISSN: 0305-8719
    Electronic ISSN: 2041-4927
    Topics: Geosciences
    Published by Geological Society (of London)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Eoarchean within-plate basalts from southwest Greenland (2013)
    Geological Society of America (GSA)
    In: Geology
    Details
    Publication Date: 2013-02-20
    Description: The majority of 〉3 Ga metabasalts have chemical features, such as high field strength element (HFSE) depletions, that are characteristic of modern island-arc basalts. These compositions have been interpreted as evidence for subduction of oceanic crust early in Earth’s history. Alternatively, the apparent absence of Archean mafic rocks with mid-oceanic ridge basalt (MORB) and ocean island basalt (OIB) compositions and the ubiquitous occurrence of metabasalts with HFSE anomalies suggest that these chemical features may instead be a widespread characteristic of the Archean mantle related to early chemical differentiation and unrelated to modern-style recycling of crust. Here we present major- and trace-element data for a suite of metabasalts from Innersuartuut Island, southwest Greenland, which have a minimum age constraint of 3.75 Ga and are likely as old as ≥3.85 Ga. Samples from Innersuartuut show no evidence for crustal contamination or subduction-related magmatism, and have a petrogenesis comparable to modern OIB. The new data demonstrate that a compositional range for volcanic rocks comparable to that seen in the Phanerozoic existed in the Eoarchean. Therefore, rather than a global anomaly, subduction-related processes are the likely origin for the compositions of the most commonly preserved Archean mafic rocks with island-arc basalt characteristics.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America (GSA)
    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...