关键词: 地壳, 岩石圈, 基本特征

Abstract:

The lithospheric structure of China and its adjacent area is very complex and has several prominent characteristic features: the continental crust of China is thick in the west but thin in  the east; and it is thick in the south but thin in the north. The continental crust of QinghaiTibet Plateau has an average thickness of 6065 km with a maximum thickness of 80 km.  while in the Eastern China it is 3035 km and the minimum thickness is only 5 km in the central sea basin of South China Sea. The average thickness of the continental crust of China reaches 47.6 km, which greatly exceeds the average thickness of 39.2 km of the global crust. The lithosphere of Chinese continent and its adjacent areas also shows  the general change tendency of thicker in the west and thinner in the east, and thicker in the south and thinner in the north. The lithosphere of QinghaiTibet Plateau and northwestern China has an average thickness of 165 km with a maximum thickness of 180200 km in the central and east part of Tarim Basin, Pamir and Changdu areas. The vast areas to the  east of the Da XingganTaihangWuling mountains including the marginal sea are the lithospheric thinning regions where the thickness of lithosphere is only 5085 km. In the western China the lithosphere and asthenosphere  behave as an obvious “layered structure”, reflecting the dynamic background of plate collision and convergence; in the eastern China, the lithosphere and asthenosphere display a “block mosaic structure”, the lithosphere is thin and the asthenosphere is very thick, reflecting the features of crustal extension and upsurge  of asthenospheric materials and forming a huge low velocity anomaly at 85250 km in east Asia and west Pacific. There is an age structure of being “older in the upper and younger in the lower” between the upper and the lower crust and between the crust and the lithospheric mantle.

Key words: crust, lithosphere, characteristic features