From Deserts to Glaciers: Magnetometry in Paleoenvironmental Studies in Central Asia

Central Asia is a vast area extending from the Caspian Sea to the western borders of China, with highly differentiated geography (high mountains, excessive deserts, grassy steppes), geology and anthropological history. As such it poses a perfect site for various studies, including paleoenvironmental and paleoclimatic research. Up to now, we performed two distinct studies in Central Asia: (1) a preliminary study on the Holocene loess-soil succession in the Karasu Valley, at the Tien Shan foothills in Uzbekistan; (2) and a study on development of high mountain lakes in the Pamir, based on lake sediments of the Rangkul Lake in the Eastern Pamir, Tajikistan (initial results presented here). In both studies we used magnetic properties of studied sediments and soils as one of parameters in multiproxy analyses. Paleosols from the Karasu Valley developed into continuous and uninterrupted sedimentary sequences interbedded with loess horizons. These sequences are characterized by diversified magnetic susceptibility values that reflect changes in their formation. Sediments form the Rangkul Lake show 5 significant shifts in deposition processes, caused by changes in water level. These shifts are clearly reflected both in sediment composition and in magnetic susceptibility of deposited material.