Monday, 27 August 2007 - 1:50 PM
1.P1.B-2

Insight into geology of East Antarctic hinterland: study of mineral inclusions from ice cores of Lake Vostok borehole

German L. Leitchenkov1, Boris V. Belyatsky1, Nickolay V. Rodionov2, and Sergey A. Sergeev2. (1) Antarctic geology, Institute for Geology and Mineral Resources of the World Ocean (VNIIOkeangeologia), Angliiskiy ave., 1, St.Petersburg, 190121, Russia, (2) CIR, VSEGEI, Sredniy ave., 74, St.Petersburg, 199106, Russia

The borehole drilled at the south part of subglacial Lake Vostok, entered into ice layer, refrozen from lake water. This layer contains random mineral inclusions, eight of which were studied using state-of the-art analytical equipment. Six inclusions are represented by soft aggregates consisting mainly of clay-mica minerals and micron-sized quartz grains while two others are clasts of solid fine-grained cemented rocks. The biggest rock clast consists of poorly-rounded quartz and minor amount of accessory minerals. More than twenty grains of zircon and monazite were identified in this siltstone and have been dated by SHRIMP-II. Analytical data yielded two age clusters ranging 0.8−1.2 Ga and 1.6−1.8 Ga. Composition of rock clasts suggests that the bedrock situated to the west of Lake Vostok is of sedimentary nature. Dated minerals allow us to presume that their provenance − Gamburtsev Mountains and Vostok Subglacial Highlands, is mainly represented by Paleoproterozoic cratons and Mesoproterozoic-Neoproterozoic mobile belts.

[Manuscript]

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