苏北桃林岩基与苏胶造山带燕山期隆升机制的探讨

Discussion on Taolin Batholith and Yanshan Upwelling Mechanism of Sujiao Orogenic Belt in North Jiangsu

苏北桃林岩基主要单元角闪石、黑云母的矿物化学研究揭示，苏胶造山带在印支期陆内双向对冲碰撞造山后，于燕山期末Ａ型花岗岩体侵位之前，由挤压向拉伸转化时期，曾发现急剧隆升。早期隆升快，为０１３９ｍｍ／ａ，中期隆升变慢，为００２３ｍｍ／ａ。山根拆沉，均衡抬升，地幔上隆，上地壳伸展造盆成山。

The mineral chemical research on the amphibole and biotite in Taolin batholith in North Jiangsu reveals that a sharp upwelling of Sujiao Orogenic Belt was taken place after the orogenic movement of intracontinental bilateral ramp collision during Indo Chinese epoch and emplacement of A type granite body before the end of Yanshan epoch when the plate movement transformed from compression to extension. Early upwelling was rapid at the speed of 0 139mm/a and middle period upwelling was slow at the speed of 0 023mm/a. There appeared the subsidence of the mountain root, uniform elevation and upwelling mantle in this period. So, the upper crust was extended and reconstructed into basins and mountains. This is the main reason for the break back of present basin range structure of Sujiao Orogenic Belt and the ultra high pressure metamorphic belt during Yanshan epoch.