Abstract
Abstract In this paper we review, and supplement, existing data to investigate the character, origin and deformation of the basal silty ice of the centre of the Greenland ice sheet as revealed in the Dye3, GRIP and GISP2 cores. A major process of basal silty ice formation in the central part of Greenland is incorporation of relict non-glacial ice at the base of the ice sheet during its development. The evidence for this can be found in a stable isotope composition study, both in δD and δ 18 O, in a total gas content and gas composition study, in a comparison of the dielectric conductivity profile and chemical profiles. Ice crystallographic investigations and the study of the isotopic compositions in Nd, Sr and Pb of the mineral particles embedded in the silty ice help to clarify the situation. The processes proposed to explain the stacked sequence developed in the basal silty ice of these central areas are folding resulting in the interbedding of silty ice and glacial ice, and flow-induced mixing related to circular motion of ice in bedrock depressions with flow separation accompanied by some entrainment of the underlying ice.
Published Version
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