QUANTITATIVE IR SPECTROSCOPIC ANALYSIS OF NON-CLAY MINERALS FROM THE BOTTOM SEDIMENTS OF LAKES BAIKAL AND HГ–VSGГ–L ( in the context of paleoclimatic reconstructions )
V.N. Stolpovskaya, E.P. Solotchina, and A.N. Zhdanova
Institute of Geology and Mineralogy, Siberian Branch of the RAS
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: IR spectroscopy, bottom sediments, quantitative analysis, quartz, plagioclase, carbonates, biogenic silica, Lakes Baikal and Hövsgöl, paleoclimate
Pages: 776-788
Abstract
The problem of paleoclimatic reconstructions in Central Asia is intimately related to study of the material composition of bottom sediments of Lakes Baikal and Hövsgöl. We report results of a quantitative IR spectroscopic analysis of non-clay components from these lacustrine sediments, such as quartz, plagioclase, carbonate minerals, and biogenic silica. The analyses were carried out using calibration curves (optical density at the absorption peak of component vs. its concentration in the sample). The calibration curves were constructed using synthetic mixtures of known composition. A method has been developed for a quantitative estimation of biogenic silica from the high-frequency shoulder of its absorption band 800 cm-1. The obtained results are in agreement with chemical data. Estimation of the total content of non-clay components made it possible to determine the portion of layered minerals in the sediments and determine its dependence on paleoclimatic conditions. The relative error of most analyses is much lower than 10%. The maximum concentration of kaolinite in the sediments is 5%.
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