Rare earth element geochemistry of Lake Baikal sediment : Its implication for geochemical response to climate change during the Last Glacial/Interglacial Transition

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Sediments deposited on the bottom of Lake Baikal have contributed to the understanding of a long-term environmental history of continents. Rare earth elements (REEs) along with major elements and loss on ignition (LOI) of Baikal sediments were determined with the aim of evaluating their suitability for a new paleoenvironmental proxy. Our interest is concentrated on paleoenvironmental change during the Last Glacial/Interglacial Transition (LGIT). Chondrite-normalized REE patterns for Baikal sediments show a similar variation to those for typical upper continental crustal materials. Three parameters of (La/Yb)n (n: chondrite-normalized value) ratio, ΣREE/TiO2 and Eu anomaly were used to express detailed characteristics of Baikal sediments. Depth profile of (La/Yb)n ratio shows abrupt change, whose timing corresponds to the beginning of climatic warming inferred from the profiles of SiO2/TiO2 and LOI. In addition, (La/Yb)n ratio, ΣREE/TiO2 and the degree of Eu anomaly correlate with each other. This suggests that inflow process of particulate materials into the lake may have changed during the Last Glacial/Interglacial Transition. The analytical results of this study lead to the conclusion that REE are a useful paleoenvironmental proxy in the Baikal region.
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