Lithological and biochemical properties in sediments of Lama Lake as indicators for the late Pleistocene and Holocene ecosystem development of the southern Taymyr Peninsula, Central Siberia

In order to evaluate the sensitivity of aquatic and terrestrial ecosystems to climatic changes, lithological (sediment structure and color, grain size , physical properties) rind biochemical (TOC, TOC/TN, delta(13)C Of TOC and carbonates) investigations were carried out on an 11.12 m-long sediment co re from Lama Lake (Central Siberia, Putorana Plateau). According to the pol len data, the sequence represents the termination of the Pleistocene, and t he entire Holocene. It is composed of highly terrigenous and stratified cla ys and silts. Sediment structure, grain-size distribution, carbonate conten ts and physical properties of the sediment indicate that glaciers were pres ent in the catchment area of Lama Lake during the period Oldest Dryas to Al lerod. For the same time period, delta(13)C values of TOC give indications of a perennial ice cover. Since the Allerod, organic matter accumulation ha s increased, caused by cm increasing input of land vegetation and aquatic p rimary production as revealed by relations TOC contents, TOC/TN ratios and delta(13)C values of TOC. During the Holocene climatic optimum, in late Pre boreal and Boreal times, biogenic primary production in Lama Lake reached i ts maximum and the vegetation in the catchment area changed from grassy tun dra to a dense forest. From the Atlantic period to the present, small varia tions in delta(13)C values Of TOC and TOC contents are probably related to the location of Lama Lake on the border between grass and wooded steppe, le ading to responses of environmental conditions to even small changes in cli mate.