山东鲁东碰撞造山型金矿成矿作用探讨

碰撞造山成矿作用是大陆动力学研究的重要内容,大地构造相编图是研究山东大陆块体离散、会聚、碰撞、造山的大陆动力学过程的主要载体和具体表达形式.作者在编制1:50万山东省大地构造相图时发现,鲁东地区中生代有两次重要的碰撞造山事件——印支和燕山碰撞造山作用.印支造山作用主要表现为扬子板块向华北板块俯冲,形成苏鲁高压-超高压变...

Study on the Orogenic Type Gold Deposits in Eastern Shandong Province

The mineralization during collision orogenesis is an important part of continental dynamic study.Mapping of the tectonic phases(1:500000) was used to study the dispersion,convergence,collision and orogeny of the continental block in Shandong Province.Duringthe mapping of tectonic phases in Shandong Province,we found that there are two important Mesozoic collision events in Eastern Shandong Province——Indosinian and Yanshannian collision.Indosinian collision orogeny was resulted from the subduction of the Yangtze plate beneath North China plate,which led to the formation of the Sulu high pressure-ultra-high pressure metamorphic belt,synorogenic granites and post-orogenic high-alkali syenites;the Yanshannian collision orogeny originated from the transformation of central Asia-Tethyan tectonic region to the coastal Pacific tectonic plate,and the subduction of the Pacific plate,which is demonstrated as three phases of orogeny and extensions in Eastern Shandong Province.Four sets of granitoids associated with orogenesis can be discerned,i.e.,the Linglong gneissic granites of early orogenic period(J3),the Guojialing granodiorite-granite of the middle orogenic period(K1),the Weideshan diorite-granodorite-granite of the late orogenic period,and in the Laoshan A-type granites of the post-orogenic.SHRIMP U-Pb age of the Guojialing orogenic granodiorite-granite assemblage in middle orogenic period is 130~126 Ma,which is closely related to gold mineralization.The ore-forming age of the gold deposits in Eastern Shandong is 120~115 Ma,which basically represents the main ore forming period.Poly-metallic mineralization is closely related to the Weideshan diorite-granodiorite-granite of late orogenic period which is a period of superimposed gold mineralization in the region.Tectonic-magmatic events and gold mineralization are controlled by the interaction of Tethys,Paleo-Asian Ocean and the Pacific tectonic regions.Dynamic background of the gold mineralization was the transition of Mesozoic tectonic regime and lithospheric thinning,which was resulted from the collision bewteen North China plate and Yangtze plate and subduction of the Pacific plate.