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Keywords:

  • Micro-Raman spectroscopy;
  • lacustrine sediments;
  • Martian palaeolakes;
  • Antarctic Dry Valleys;
  • Mars analogues

Abstract

A Raman spectroscopic study was performed on igneous sediments dominated by plagioclase, K-feldspar, quartz and pyroxene from the Dry Valleys region of Antarctica. Lakes from this region of Antarctica have been investigated as possible analogues for paleolake environments on early Mars. Gaining Raman spectra of such sediments provides compositional information for missions to Mars, and also the necessary ground truthing for use of Raman spectroscopy for exploration of geology, and perhaps biology, on Mars. Sediments measured in this study were collected from the perennially ice-covered Lake Hoare in the Taylor Valley and include surface sediments, and lakebottom sediments from oxic and anoxic zones of the lake. Micro-Raman spectroscopy provides a unique opportunity for in situ exploration of biogeochemical processes on the micron scale at field sites. For example, in these potential paleolake analogue sediments, ∼5 µm sized sulfide deposits were observed on the surface of quartz grains in one of the anoxic sediments. Small amounts of calcite, organics, clays and iron oxides/hydroxides were also identified. Copyright © 2004 John Wiley & Sons, Ltd.