Oehlerich, Markus; Mayr, Christoph; Griesshaber, Erika; Luecke, Andreas; Oeckler, Oliver M.; Ohlendorf, Christian; Schmahl, Wolfgang W.; Zolitschka, Bernd
Ikaite precipitation in a lacustrine environment - implications for palaeoclimatic studies using carbonates from Laguna Potrok Aike (Patagonia, Argentina).
In: Quaternary Science Reviews, Vol. 71, No. SI: pp. 46-53
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The monoclinic mineral ikaite (CaCO3 center dot 6H(2)O) and itspseudomorphs are potentially important archives for palaeoenvironmentalreconstructions. Natural ikaite occurs in a small temperature range nearfreezing point and is reported mainly from marine and only rarely fromcontinental aquatic environments. Ikaite transforms to more stableanhydrous forms of CaCO3 after an increase in temperature or whenexposed to atmospheric conditions. The knowledge about conditions fornatural ikaite formation, its stable isotope fractionation factors andisotopic changes during transformation to calcite is very restricted.Here, for the first time, primary precipitation of idiomorphic ikaiteand its calcite pseudomorphs are reported from a subsaline lake, LagunaPotrok Aike, in southern Argentina. The calculated stable oxygen isotopefractionation factor between lake water and ikaite-derived calcite