LANZHOU, Oct. 24 (Xinhuanet) -- China's eighth largest desert, the Kumtag, measures 22,917.2 square kilometers, according to scientists who have just returned from a month-long expedition across the Kumtag.

    This is the first time for Chinese scientists to measure the exact size of the Kumtag, which is located between Lop Nur in Xinjiang Ugyur Autonomous Region and Dunhuang of Gansu Province and sandwiched between two mountain ranges: the Tianshan Mountains on the north and Altun Mountains on the south.

    A team of 15 scientists participated in the expedition, the first full-scale scientific expedition across the desert, said Wang Jihe, a researcher with Gansu Provincial Sand Control Institute and head of the expedition.

    The scientists, representing Gansu Provincial Sand Control Institute, Chinese Academy of Forestry Science and Lanzhou University, walked more than 5,000 kilometers across the desert and used remote sensing satellite images, coupled with results of field surveys, to work out the precise area of the desert, said Wang.

    They also collected more than 500 samples of desert animals and vegetation and at least 1,000 first-hand geological data, discovered two stratum sections that have proven valuable to scientific research, and provided evidences to support further study on the desert's geological conditions, soil, vegetation, climate changes and changing river and lake systems.

    Underneath the Kumtag's sand and rock, the scientists found clear signs of a vast dried-up lake. Wang said the team collected more than 100 samples of the stratum and hoped further analysis into the samples may tell how the rise of the Qinghai-Tibet Plateau induced climate changes in the arid northwest, how Kumtag came into being and how Lop Nur, once a vast lake, kept shrinking and dried up entirely in 1972.

    The expedition team also spotted 25 wild two-humped camels, a critically-endangered species, in the central part of the desert. According to Ma Muli, a forestry official in Jiuquan city of Gansu, Kumtag is home to about 260 of the camels. "Most of them have moved here after the Lop Nur dried up," said Ma, who is also guide for the expedition team.

    Very little is known about the Kumtag, whose name means "sand hill" in Ugyur. As its name suggests, the desert has the toughest natural conditions in northwest China's arid region. Enditem