青海鄂拉山地区铜多金属矿床的成矿条件及成矿模式

METALLOGENIC CONDITIONS AND MODEL OF COPPER-MULTI-METAL DEPOSITS IN NGOLA SHAN REGION,QINGHAI PROVINCE

青海鄂拉山地区为海南三叠纪沉积盆地西缘的北北西向印支期构造－岩浆活动带，其交切柴达木地台边缘东昆仑近东西向构造。其中铜多金属矿床形成于盆地裂陷和陆内俯冲一滑脱造山期。盆地裂陷后期（Ｔ２）海相基性火山岩喷发前，热水活动形成了铜峪沟铜矿床，同时也形成了区域性含Ｃｕ等成矿元素高的“矿源层”；在造山期（Ｔ２未－Ｔ３），通过区域动热变质和岩浆气液交代，形成日龙沟沉积－变质锡多金属矿床、赛什塘沉积－变质－岩浆热液叠加铜矿床、索拉沟多金属矿床及尕科合岩浆热液交代－充填式含铜银砷矿床和什多龙铅锌矿床．文中扼要地阐述了矿床受地层、岩浆岩、构造及交代岩控制的特点，强调鄂拉山地区的南段，既是北北西断裂与东西向基底断裂交汇部位，有利于海底热水成矿，同时这里还是陆壳俯冲－滑脱构造强烈地段，对变质和岩浆热液有集、迁移和储存也较有利。

Ngola Shan region,Qinghai province,located on the western margin of Hainan Triassic sedimentary basin,is a tectonomagmatic mobile belt in a NNW direction.It intersects the eastern Kunlun Shan tectonic belt in a E-W direction on the southeastern margin of Qaidam platform.The copper-multi-metal deposits in this region formed in the Hainan basin rifting and intracontinental subduction-decoiiement orogenic period. Before the Middle Triassic marine basic volcanic eruption during the late stage of rifting of Hainan basin,the submarine thermal water activities formed the Tongyugou copper deposit and the regional source beds containing rich metallogenic materials such as copper,etc.In the orogenic period(the latest Middle Triassic to the Late Triassic),on the basis of the source beds,the regional dynamothermal metamorphism and the magmatic hydrothermal replacement,there formed a series of copper-multi-metal deposits,e.g.Rilonggou sedimentary metamorphic tin-multimetal deposit,Saishitang sedimentary metamorphic and magmatic hydrothermal superimposed copper deposit,Suolagou multimetal deposit,and Gakehe magmatic hydrothermal replacement-filling cupreous silver-arsenic deposit and Shiduolong sham lead-zinc deposit.This paper briefly illustrates the characteristics of the deposits controlled by strata structure,magmatite and metasomatite.It emphasizes that the southern segment of Ngola Shan region is located in not only the intersected position between the NNW faults and the EW basement faults but also in strong active zone of intracontinental subduction and decollement, where is favourable for the submarine thermal water mineralization and the metamorphic and magmatic hydrothermal mineralization.