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Mikhalsky E.V.,VNIIOkeangeologia | Henjes-Kunst F.,Bundesanstalt fur Geowissenschaften und Rohstoffe | Belyatsky B.V.,VNIIOkeangeologia | Roland N.W.,Bundesanstalt fur Geowissenschaften und Rohstoffe | Sergeev S.A.,VSEGEI
Precambrian Research

We report isotopic (Sm-Nd, Rb-Sr and zircon Hf and U-Pb SIMS SHRIMP) data on rocks collected from various localities throughout the southern Prince Charles Mountains known as the Ruker Province. The area is made up of a high-grade metamorphic basement, overlain by variably deformed and metamorphosed supracrustal associations of Proterozoic age. The area comprises two distinct tectonic terranes, experienced major tectonothermal processes in the Archaean (ca. 3400-2800. Ma: the Ruker Terrane) or in the Palaeoproterozoic (ca. 2500-2100. Ma: the Lambert Terrane). New zircon U-Pb ages of ca. 3180-3150. Ma, ca. 2800, and ca. 2500. Ma were obtained for various orthometamorphic rocks from the Ruker Terrane and ca. 2200. Ma, ca. 1740. Ma, and ca. 920. Ma for syn-tectonic granitic veins and leucosomes from the Lambert Terrane. The Sm-Nd data provide evidence for the initial separation of the continental crust of the Ruker Terrane from the mantle mainly between ca. 3.2 and 3.4. Ga, but up to 3.8. Ga, and indicate the presence of two mantle reservoirs which correspond to (1) depleted to slightly enriched, and (2) ultra-depleted mantle. Some material was also derived from the mantle at ca. 2.7-3.0. Ga; the crust of this age apparently underlies the central part of the Ruker Terrane (the Cumpston. Massif-Mt Newton block), which is also distinguished by younger (ca. 2.5-2.1. Ga) zircon ages. The Lambert Terrane contains subordinate ca. 3.6-3.8. Ga protoliths, and the bulk of the crust seems to have originated between 2.6-2.9. Ga from various mantle sources and it may represent an accretional complex onto the Archaean Ruker Terrane.We also summarize published isotopic data and propose an integrated geological evolution for both terranes of the Ruker Province, discuss its relationships with the bordering Rayner Province, and compare its isotopic features with other Precambrian cratons of Gondwana. The key geological features of the Ruker Terrane suggest a similarity to the Yilgarn Craton, which would imply considerable mineral resource potential of the Prince Charles Mountains. © 2010 Elsevier B.V. Source

Sobolev P.O.,VSEGEI
Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources

The Cenozoic regional uplift remains very poor investigated for the Russian part of the Barents Sea. Several methods were used to estimate magnitude of the uplift and erosion for the Eastern Barents Sea. First method was related with using of generalized porosity-depth trends. Geophysical well logging data from the Russian Barens Sea (about thirty deep offshore wells) were compiled and processed. The joint interpretation of sonic, gamma-ray, resistivity, spontaneous potential logs were used to calculate porosity and shale fraction for siliciclastic rocks. Comparison of smoothed exponential porosity-depth curves from different wells reveals the rate of compaction for the different kinds of sediments (sands, silts and shales) and different level of erosion. Similar results were obtained with Magara's approach for sonic logs of shales. We used vitrinite reflectance data for the independent evaluation of the uplift and for calibration. Combining the data on wells we have determinated uplifts ranging from 300 m in the south (Pechora Sea) to 700 m in the central part of the South-Barents deep and to 2 km in the Franz-Joseph Land. The magnitude of erosion increase eastward as well. Seismic profiles and structural maps were used to trace and interpolate the estimates of uplift between wells. Source

Sobolev P.O.,VSEGEI | Soloviev A.V.,Russian Academy of Sciences
75th European Association of Geoscientists and Engineers Conference and Exhibition 2013 Incorporating SPE EUROPEC 2013: Changing Frontiers

The regional Late Cretaceous-Cenozoic exhumation event is rather poor investigated for the Russian part of the Barents Sea. Recently interpretation of existing offshore well logs for the Russian Barents Sea was performed and generalized porosity-depth trends were compiled (Sobolev, 2012). The results of porosity-depth analysis were supplemented with sonic log interpretation and vitrinite reflectance data to provide assessment of the total Mesozoic-Cenozoic exhumation magnitude. In this study we extended the latter approach to interpolate the results from wells using seismic velocity data from common-depth point seismic reflection surveys. The previous point assessments of the regional Cenozoic exhumation magnitude were significantly improved. Differential exhumation throughout the province has occurred. The least uplift and erosion (400-500 m) occur in the depocenters of both South and North Barents Sea Basins. The combined fission-track and U/Pb dating of apatite by LA-ICP-MS was used for reconstruction of the thermal history. The apatite from all 13 samples (Fersmanovskaya-1 well) was dated is partially annealed. The tentative interpretation of fission-track data shows that the Lower Triassic - Lower Jurassic rocks, apparently, used to be within the partial annealing zone in Middle Jurassic - Cretaceous, and an acceleration of exhumation occurred in Early Paleogene (∼60 Ma). Copyright © (2012) by the European Association of Geoscientists & Engineers All rights reserved. Source

Petrov O.V.,VSEGEI | Smelror M.,Geological Survey of Norway
Polar Record

Following an initiative taken by the Russian Ministry of Natural resources and Ecology and by the Federal Agency of Mineral Resources (Rosnedra) in 2003 international cooperation on compiling a new generation of circum-Arctic geological and geophysical maps (in scale 1: 5 000 000) was undertaken by a consortium of national agencies from Canada, Denmark, Finland, Norway, Russia, Sweden and the USA. The polar stereographic maps include onshore and offshore geological coverage to 60° N. The bedrock map and database was first published in 2008, the geophysical maps were completed in 2010, while a tectonic map is currently in press. The new circum-Arctic maps are formally published under the Comission for the Geological Map of the World (CGMW/CCGM). A metallogenic map and database of the main occurrences of onshore and offshore metal deposits is scheduled to be completed in 2016. Copyright © 2014 Cambridge University Press. Source

Breitkreuz C.,TU Bergakademie Freiberg | Eliwa H.,Menoufia University | Khalaf I.,Menoufia University | Gameel K.E.,TU Bergakademie Freiberg | And 5 more authors.
Precambrian Research

Chronology of Neoproterozoic volcanosedimentary successions remains controversial for many regions of the Arabian-Nubian Shield, including the Dokhan Volcanics of NE Egypt. New U-Pb zircon SHRIMP ages have been obtained for 10 silica-rich ignimbrites and two subvolcanic dacitic bodies, mapped as Dokhan Volcanics, from the North Eastern Desert of Egypt. Crystallization ages range between 592 ± 5 and 630 ± 6. Ma (Early Ediacaran). Apparently, the late consolidation of the Arabian-Nubian Shield was accompanied by the evolution of isolated volcanic centres and basin systems which developed during a period of approx. 40. Ma, independently in space and time and probably under changing tectonic regimes. The obtained age data together with other previously published reliable ages for Dokhan Volcanics suggest two main pulses of volcanic activity: 630-623. Ma and 618-592. Ma. Five samples contain inherited zircons, with ages of 669, 715-746, 847 and 1530. Ma, supporting models that North Eastern Desert crust is mainly juvenile Neoproterozoic crust. © 2010 Elsevier B.V. Source

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