长江形成的大地构造背景与沿江带的环境效应

长江上游金沙江段的展布形态为一向NE凸出的弧形,宜宾-宜昌段主要为向NW凸出的弧形;中游近似于"S”形;而下游则是向N凸出的弧形.这一特殊的自然地理面貌严格受青藏地块、秦祁昆地块和扬子板块的构造格局控制,是特提斯构造系统和太平洋构造系统及其二者复合作用的结果.沿长江地带的地震活动是上述两大构造系统下,新构造运动所致,在二者的接合部位地震活动最强烈.长江沿岸的地质灾害严格受岸坡的岩石类型、结构面规模以及产状等因素的影响.因此,长江的形成和沿江带的环境效应与大地构造背景密切相关.

Tectonic origin of Yangtze river and environmental result along Yangtze river belt

The geomorphic feature of Yangtze river is controlled by the tectonic framework of the Qinghai Tibet block,Qinling Qilian Kunlun block and the Yangtze plate,and it is the result of the tectonic process of both Tethys tectonics and Pacific tectonics.In Jinshajiang region tectonic movements is stronger because of the collision of both Qinghai Tibet block and Yangtze plate there.Earthquake along Yangtze river results from the new structural movement which is under the control of both Tethys tectonics and Pacific tectonics.Most earthquake movements occur in the collision belt of both Qinghai Tibet block and Yangtze plate.Geological hazards along Yangtze river are affected by both rock type and structural surface feature.