东秦岭造山带印支—燕山构造体制转换过程中岩浆活动与成矿作用浅议

A BRIEF DISCUSSION ON MAGMATIC ACTIVITIES AND METALLOGENIC ACTIVITIES DURING THE TRANSFORMATION OF INDO-YANSHAN TECTONIC SYSTEM IN EASTERN QINLING OROGENIC BELT

东秦岭在印支运动期末原商丹洋与勉略洋已经消失,华北、秦岭及扬子地块已完成拼合,但进入燕山构造期时的陆内造山作用总体南北向的地壳收缩,也就是华北和扬子的相向运动并未停止。同时,太平洋板块向亚洲大陆之下俯冲作用的远程效应已深刻影响到东秦岭地壳深部。在地表和深部两种不同性质与方向动力作用下,东秦岭地区形成了独特地质构造与岩浆岩组合,最终形成了地表东西向,深部南北向、且南北向构造由深到浅既逐渐置换东西向构造二者又相互并存的立交桥式造山结构。同时分别发育造山型和幔源浆混两类不同类型的岩浆活动,伴随不同组合的成矿作用。印支—燕山期是东秦岭最为重要的一次构造体制的转换与地壳结构的重种大调整,也是东秦岭最重要一次的金、钨、钼、铅、锌、汞、锑等多金属成矿期。

At the end of the Indosinian Movement,the former Shang-Dan Ocean and Mian-Lue Ocean disappeared and the North China block,the Qinling and Yangtze blocks have been assembled.However,the continental orogeny during the Yanshanian tectonic period generally contracted at north-south direction,which means that the opposite movement of North China and the Yangtze was still in moving.Meanwhile,the remote effect of subduction under the Pacific Plate deeply affected the deep crust of the East Qinling Mountains.The formation of unique geological structure and magmatic rock assemblage in the eastern Qinling area under the dynamic action of different nature and direction of surface and deep,the overpass orogenic structure of the east-west direction,the deep north-south direction and the north-south direction formed,and the structure from deep to shallow was gradually replaced by the east-west direction structure and coexisted with each other.At the same time,two different types of magmatic activities of orogeny and mantle source slurry developed and accompanied with different mineralization.The Indosinian-Yanshan period was the most important transition of the tectonic system and re-speculation adjustment of crustal structure in the East Qinling Mountains,which is also the most important metallogenic period of gold,tungsten,molybdenum,lead,zinc,mercury,antimony and so on.