A 2000-year dust storm record from Lake Sugan in the dust source area of arid China



[1] Arid northwestern China is considered to be a major source of atmospheric dust supply to the Northern Hemisphere. However, dust storm evolution and dust emission processes in the past remain unclear due to the scarcity of geologic archives in this region. Hydrologically closed lakes in dust source areas act as a trap, providing the opportunity to trace the history of dust emission or eolian activity. Here we present the results of dust storm proxies and a dust storm history from Lake Sugan in the Qaidam Basin, a dust source area, on the northern Qinghai-Tibetan Plateau. Grain size analyses of the materials deposited during modern dust storms and of the lake surface sediments demonstrate that the coarse component of the lake sediments was transported primarily by ambient winds when dust storms occurred. In combination with a sediment chronology generated by counting annual laminations, a 2000-year dust storm history was reconstructed on the basis of changes in the coarse component and magnetic susceptibility of the lake sediments. Frequent and/or intensive dust storms occurred during the intervals AD 300–500, AD 1180–1240, and AD 1500–1700. The occurrence of dust storms largely coincided with the strengthening of the Siberian High with colder air masses from high latitudes, such as during the Little Ice Age, frequently encroaching into the dust source areas in northwestern China. Our results suggest that wind strength plays an important role in dust emissions in arid source areas. However, dust storms in the late 20th century are most likely associated with disturbance of the ground surface caused by petroleum exploitation in the Qaidam Basin.