华北古大陆南缘构造格架与成矿

Geotectonic Framework and Metallogenic System in the South Margin of North China Paleocontinent

东秦岭地区在前海西期表现为大陆边缘的构造活动,到海西期后特别是燕山期已属于陆内造山作用,因此称之为古大陆边缘。在对前海西期构造格架重塑的基础上,以不同建造、岩浆活动和分隔构造单元断裂资料分析为依据,以控制不同构造单元的断裂为界,自北而南将构造单元划分为:华山-熊耳山陆缘带、宽坪陆缘增生带、二郎坪弧后断陷带、秦岭古岛弧带和南秦岭泥盆纪断陷海盆。据陆缘构造发展阶段的沉积建造和岩石组合特点分为:华北陆块南缘太古宙古陆核边缘活动性沉积、早元古代华北陆块南缘古陆核边缘活动性缓慢沉积、中-新元古代华北陆块南缘拉张构造体制下的被动陆缘、加里东早期华北古陆南缘活动陆缘、早古生代华北陆块南缘太平洋型活动大陆边缘;中生代扬子与华北板块已经拼接,进一步发生陆内A型俯冲,构造型式为近南北向的深部构造作用。根据区域成矿的物质组成以及空间和时间上的分布特点,划分为5个成矿系统:前长城纪陆核活动性边缘沉积成矿系统、中-新元古代被动大陆边缘成矿系统、早加里东期构造体制转换期成矿系统、古生代活动大陆边缘成矿系统和中生代陆内碰撞造山成矿系统。

According to the tectonic characteristics of the research area in the south margin of North China paleocontinent, the geotectonic framework of the area could be divided into the Huashan-Xong＇ er mountains continental margin belt, the Kuanping Late Proterozoic accretion belt, the Erlangping margin basins zone, the Qinling dispersion type island arc terrain, and the sedimentary basins of Nanqinling zone. In the light of sediment build evolution stage and metallogenesis, these could be classified as follows： the sediment build in the active south margin of North China Paleocontinent in the pro-Mesoproterozoic, the sediment build in the passive continent margin in the Middle-Late Proterozoic, the sediment build in the coveres type continent margin in the early Paleozoic, the sediment build in the active margin in the Paleozoic and the phase of collision in the Mesozoic. According to the characteristics of tectonic evolution stage and metallogenesis with the research area in the eastern Qinling, these meallogenic system could be classified as follows： 1） the metallogenic system in the active south margin of North China Paleocontinent in the pro- Mesoproterozoic; 2） the metallohenic system in the anactive continent margin in the Middle-Late proterozoic; 3） the metallogenic system in the coverse type continent margin in the early Paleozoic; 4） the metallogenic system in the active margin in the Paleozoic; 5） the metallogenic system in the collision margin in the Mesozoic.