青藏高原重力构造

青藏高原的范围大致由昆仑山、阿尔金山、祁连山、龙门山及喜马拉雅山所围限。是一个边部群峰耸立、内部相对平坦的广阔高原,具有山高地势平的地貌景观。地壳厚度一般为50—70公里,成为全球地势最高、地壳最厚的地区。 中新世晚期,喜马拉雅尚未成山,其高度接近海面,仅约数百米。而由冈底斯山至昆仑山的广大地区,此时形成了统一的夷平面,具有与喜马拉雅地区相似的高度。

GRAVITY TECTONICS OF THE CHINGHAI-TIBETAN PLATEAU

The distribution of the seismic activities, recent tectonic patterns, gravity anomalies, crustal structure, geomorphological features and other phenomena in Chinghai-Tibetan Plateau and its surroundings possess axial symmetrical characters concerning the center of the plateau.Such a phenomenon can not be explained by the lateral compression due to the collision of two continental plates.The authors suggest that the simultaneous rise of Chinghai-Tibetan Plateau in large scale is caused by gravitational instability during the differentiation of mantle materials.The horizontal stresses are generated within the plateau crust by gravity effect. The axial symmetrical distribution of various phenomena is associated with the action of these horizontal stresses which are the main driving forces of the recent tectonic movements in Chinghai-Tibetan Plateau and its surroundings.The above considerations show that the paramount cause of the uplift of the Chinghai-Tibetan Plateau and its effect on the surroundings is owing to the gravitational instability. Therefore the tectonic phenomena of Chinghai-Tibetan Plateau should be accounted for the gravity tectonic model as viewed from its origin and evolution.