137Cs dating of lacustrine sediments and human impacts on Dalian Lake, Qinghai Province, China

137Cs and grain-size analyses indicate the total amounts of 137Cs deposited by wind and water in the Dalian Lake of Gonghe Basin, Qinghai Province. The vertical profile of 137Cs in the lacustrine sediments shows three 137Cs activity peaks and one trough: the main peak corresponds to the global 137Cs fallout in 1963; the two secondary peaks correspond to the leakage of the Chernobyl reactor in 1986 and complete desiccation of the lake in 1994. The trough corresponds to aeolian deposition caused by extensive reclamation of farmland in late 1980s and early 1990s. The 137Cs dating was used to evaluate sedimentation rates in Dalian Lake since 1963. They are divided into three periods: two with slow deposition (1963–1986 and 1994–1998), and one with rapid deposition (1986–1994). 137Cs seems to have the same potential for indicating environmental changes and human interference in the arid and semiarid regions as in humid regions.