金沙江转换断层沉积盆地

金沙江断裂带位于青藏高原的东部(这里说的金沙江是指流经西藏和四川分界线的一段)。笔者认为,该断裂带是一条近南北走向的古代转换断层。在这个断裂带内,存在一个二叠纪—中三叠世的转换断层沉积盆地。这个古盆地里面的岩浆和沉积建造部分保存到今天。

THE JINSHA RIVER TRANSFORM FAULT SEDIMENTARY BASIN

The tectonic nature of the Jinsha River fault and the sedimentary characteristics of the Jinsha River basin are discussed.The Jinsha River fault is a north-south trending transform fault which developed in a shallow sea environment. The fault was active from the Permian to the Middle Triassic, and the Jinsha River sedimentary basin formed as a result of the horizontal displacement along it.During the nearly 80 m.y. of transform fault activity, the Tanggula plate on the western side of the fault slided northward for at least 700 km; at the same time the Jinsha River sedimentary basin developed three types of crust: from north to south, continental crust, transitional crust and, finally, oceanic crust.During Middle Triassic, the Tanggula plate collided with a continental block to the north, bringing the transform fault activity to an end; closure of the Jinsha River transform fault sedimentary basin by an transverse compression followed.Four characteristics of transform fault sedimentary basins in general are summarized.