Characterisation of sediments of the Tarn Flat lake (Antarctica)

XRD, INAA and Fe-57 Mossbauer data for a sedimentary core of the small lake of Tarn Flat in the region of Terra Nova Bay are reported and discussed. T he lake sediments consist of quartz, muscovite, feldspars, calcite, fluorit e and chlorite. Iron is present as Fe(II) in chlorite for about 16%, as Fe( III) up to 74% and in ferrihydrite for the remaining 10% of the total iron content. The specimens from the border of the Tarn Flat lake contain amphiboles in a ddition to the silicates found in the sediment but less calcite and fluorit e. Their iron chemistry differs from that of the sediment, in particular fo r the lower Fe(III) content. The specimens from the borders of other lakes present in the region of Terra Nova do not contain calcite or fluorite and differ substantially for silicate-composition. The sediments of the Tarn Flat lake derive from local materials, modified i n silicate fraction and enriched in calcite and fluorite.