Chinese scientists find landform left by glacial erosion

Chinese scientists claimed to have identified a landform left by glacial erosion at least two million years ago on the Qinghai-Tibet Plateau.

The erosion,on the southeast edge of the plateau and bordering the western provinces of Gansu and Sichuan,started two million to three million years ago and ended about 20,000 years ago,said Shen Yongping,a researcher with the Cold and Arid Regions Environmental and Engineering Research Institute.

Shen and his colleagues from the Lanzhou-based institute are planning to complete the expedition before the end of this year,according to the official Xinhua newsagency.

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The landform,with an average altitude of 3,500 meters atop the Zhagana Mountains in Diebu County of Gansu Province,was first discovered by filmmakers from a cultural promotion company in Lanzhou in 2007.

Shen said he had visited the site last year and saw U-shaped valleys,steep ridges and enlarged hollows. These are typical landscape features formed by glacial erosion. During the expedition,Shen and his colleagues would further study its geological structure and environmental evolution.

He said the discovery would provide important data for research on Quaternary glaciers as well as the geography and climate changes in western China.

Glacial erosion refers to the wearing-down and removal of rocks and soil by a glacier.

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The most extensive period of recent glacial erosion was the Pleistocene era (1.6 million to 10,000 years ago) of the Quaternary period,when the polar icecaps repeatedly advanced and retreated over a period of 2 million to 3 million years.

China has 59,406 square kilometers of glaciers,about 14.5 per cent of the worlds total. Tibet alone has 28,645 square km of glaciers.

Yet scientists say Chinas glaciers have shrunk by 5.5 per cent,or 3,248 square kilometers in the past 40 years as a result of global warming.