吉林山门银金矿床地质特征及成矿模式

The geological features and metallogenic model of Shanmen Ag-Au deposit

矿床分布于北北东向伊通 -依兰深断裂与北西向断裂交汇部位的北西侧 ,受深断裂旁侧隆起区次级平行断裂带控制。矿体产于印支期花岗闪长岩与上奥陶统石缝组接触带。矿石为贫硫化物型矿石。含银矿物有自然银、辉银矿、锌银黝铜矿、硫砷银铜矿、硫锑铜银矿、银金矿等。金的独立矿物为自然金、银金矿、金银矿 ,以银金矿为主 ,部分金分散在硫化物中。成矿温度为 1 50～ 1 83℃ ;盐度为 4 4 8%～ 6 4 3% ,成矿压力为 4 4 3～ 79 1MPa。矿石硫显深源硫特点 ,铅为壳幔混合铅 ,属较年轻太平洋岛弧型正常铅 ;热液水来自天水和深源水的混合 ;矿床属浅成低温热液型矿床。成矿时代晚于 1 2 2Ma,属燕山晚期成矿。

The ore deposit is distributed on the northern side of the intersection between the NNE trending Yitong-Yilan deep fault and the NW trending fault and is controlled by the secondary parallel fault zone of the upwelling area in the side of the deep fault. The ore bodies are located in the contact zone between Indo-China granodiorite and the Shifeng Group of Ordovician System.Ore is of the lean sulfide type. Ag-bearing minerals are native silver, argentite, Ag-bearing erythroconite, Ag-bearing seligmannite, polybasite and electrum. Individual Au minerals are native gold, electrum,kustelite.The main Au mineral is electrum, and part of gold is despersed in sulfide. The research on fluid inclusion shows that the ore-forming temperature is 150～183℃,salinity is 4 48%～6 43%;the ore-forming pressure is 44 3～79 1 MPa.Research results of isotope show that ore sulfur possesses character of deep-source sulfur. Pb-isotope is crust-mantle mixed Pb of the young Pacific island arc normal Pb type. Hydrothermal solution is derived from mixture of meteoric water with deep-source water. The ore deposit bears low temperature shallow-seated hydrothemal feature. The ore-forming epoch is later than 122 Ma and belongs to late Yanshan period.