The Vostok (East Antarctica, 78°S, 106°E) ice core preserves, below the meteoric ice keeping the climatic memory of the last 420 000 years, ice formed by freezing of subglacial Lake Vostok water. This latter contains some bedrock fragments representing unique samples for the geological investigation of the East Antarctic Plateau, covered by ∼2-4km of ice. The first geochemical (<sup>87</sup>Sr/<sup>86</sup>Sr versus <sup>143</sup>Nd/<sup>144</sup>Nd) and mineralogical characterization of these inclusions as well as the dating of one of them (Nd model age on whole-rock sample) has given evidence for a Mid-Proterozoic age of the basement lying below the ice sheet, consistent with recent geophysical data. The geochemical characteristics of bedrock inclusions within the accreted ice zone are markedly different from those of the mineral dust of aeolian origin archived in the uppermost part of the Vostok ice core and originating from deflation of the Southern Hemisphere continents, and easily discriminates between the two contributions. © CSIRO 2004.
Delmonte, B., Petit, J., Basile Doelsch, I., Lipenkov, V., Maggi, V. (2004). First characterization and dating of East Antarctic bedrock inclusion form subglacial Lake Vostok accretion ice. ENVIRONMENTAL CHEMISTRY, 1(2), 90-94 [10.1071/EN04029].
First characterization and dating of East Antarctic bedrock inclusion form subglacial Lake Vostok accretion ice
DELMONTE, BARBARA;MAGGI, VALTER
2004
Abstract
The Vostok (East Antarctica, 78°S, 106°E) ice core preserves, below the meteoric ice keeping the climatic memory of the last 420 000 years, ice formed by freezing of subglacial Lake Vostok water. This latter contains some bedrock fragments representing unique samples for the geological investigation of the East Antarctic Plateau, covered by ∼2-4km of ice. The first geochemical (87Sr/86Sr versus 143Nd/144Nd) and mineralogical characterization of these inclusions as well as the dating of one of them (Nd model age on whole-rock sample) has given evidence for a Mid-Proterozoic age of the basement lying below the ice sheet, consistent with recent geophysical data. The geochemical characteristics of bedrock inclusions within the accreted ice zone are markedly different from those of the mineral dust of aeolian origin archived in the uppermost part of the Vostok ice core and originating from deflation of the Southern Hemisphere continents, and easily discriminates between the two contributions. © CSIRO 2004.
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