干旱区生态环境知识资源中心

Located in southwestern Inner Mongolia in northern China, the Ulan Buh Desert (UBD) has evolved significantly during the Holocene. The northern desert is adjacent to Hetao Plain, an important agriculture area since the Han Dynasty (similar to 200 B.C.). A series of aeolian sand-lacustrine sequences from the desert were measured and dated by using differential global positioning system (DGPS) and optically stimulated luminescence (OSL) technologies respectively. These lacustrine remains with similar deposit sequences have almost identical elevations and depositional ages, indicating that they belonged to a unified paleolake. In addition, the Holocene paleolake/desert evolution process in UBD is established. Aeolian activity prevailed before similar to 8.3 ka, and a unified Ulan Buh Paleolake containing the modern Jilantai Salt Lake covered the northern desert during 7.8-7.1 ka ago. The paleolake shrank and broke apart after 6.5 ka ago. Thereafter, the paleolake evolved into the modem UBD and Jilantai Salt Lake. The study of one sand-lacustrine section at the southern edge of Hetao Plain shows that the Tushenze Paleolake had a similar evolution process to Ulan Buh Paleolake, though they may not be connected to each other, as suggested by the elevation difference. The Ulan Buh desert-lake evolution was likely due to the climate changes in the monsoon-influenced region during the early-middle Holocene. (C) 2012 Elsevier B.V. All rights reserved.