The Loess Plateau has been proved to have been a lake and the current peak an islet some 60 million years ago. Archaeologists and geologists were able to confirm this after testing ancient fossils found at the site. Long, long ago, the region of Guyuan in northwest China's Ningxia Hui Autonomous Region, was an ocean. Some 60 million years ago, the earths crust shifted somewhere there. A violent land uprising occurred in Liupan Moutain and Moon Mountain (both located in Guyuan county) about 240,000 years ago. Loess was deposited on hilly land and alluvial conglomerate and clay were deposited in the centre of the basin centre because of the periodic land uprisings in the mountains. A large amount of loess piled up, covering the hill. This became what is currently recognized as the Loess Plateau. The Loess Plateau is the world's largest loess plateau, covering the entire territory of Shanxi province, part of Shannxi and Gansu provinces, and Ningxia Hui Autonomous Region.
