杨铁铮.黑龙江东安金矿床成矿流体的演化[J].矿产勘查,2017,8(5):799-808 |
黑龙江东安金矿床成矿流体的演化 |
Evolution of ore-forming fluid in the Dongan gold deposit,Heilongjiang |
投稿时间:2017-02-08 |
DOI: |
中文关键词: 流体包裹体 浅成低温热液型金矿 东安金矿 黑龙江 |
英文关键词: fluid inclusion, epithermal gold deposit, Dongan gold deposit,Heilongjiang |
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中文摘要: |
黑龙江省东安金矿位于兴安岭内蒙地槽褶皱区的松嫩地块与佳木斯地块的结合部。矿体直接受近SN-NNW-NW向断裂构造控制,赋存于强硅化构造蚀变带中。矿体呈脉状,陡倾斜。主要矿石矿物黄铁矿,少量黄铜矿、方铅矿、闪锌矿等。围岩蚀变以硅化、绢云母化、冰长石化、绿泥石化等为主。成矿过程从早到晚分为3个阶段:绢云母石英阶段、石英—绿泥石—硫化物阶段、玉髓萤石阶段。不同成矿阶段的石英或冰长石中多发育有流体包裹体,在成矿早期和成矿期L-V型包裹体较为发育,成矿晚期L型包裹体较发育,3个阶段的平均均一温度分别为268.5℃、249.7℃和197.6℃,平均盐度分别为5.1%、4.3%和3.5%,各阶段成矿压力范围为60.5~71.8 MPa,成矿深度范围为1.55~2.16 km,主成矿期的平均成矿压力为67 MPa,平均成矿深度为1.98 km,指示着东安金矿的成矿流体是一种混合流体,是成矿热液在向上运移过程中与浅部呈酸性的大气降水发生了混合作用的产物,在主成矿阶段,反映出是一种中低温、低压、低盐度,富含CO2、CO、CH4等挥发组分的Ca2+、Na+、K+、Cl-、SO2-4、(F-)型弱酸性的热水溶液。 |
英文摘要: |
The Dongan gold deposit in Xunke county, Heilongjiang Province, is located in the circum-Pacific metallogenic domain. Dongan gold deposit is a low sulfidation epithermal gold deposit, the gold orebodies were controlled by NS-trending structures and distributed in fractured altered zone in forms of vein and subvertical vein. Ore minerals include pyrite, galena, chalcopyrite, chalcocite, sphalerite, arsenopyrite, electrum and native silver. The hydrothermal ore-forming process was divided into early, intermediate and late stages, characterized with sericite-quartz, quartz-pyrite and chalcedony-fluoriter espectively. In the early and intermediate stages, the main fluid inclusion type is L-V, and type L in the late stage. The average homogenization temperature is 268.5℃, 249.7℃ and 197.6℃ respectively, average salinity is 5.1%, 4.3% and 3.5% NaCl equivalent, and the pressure ranges from 60.5 MPa to 71.8 MPa, the depth ranges from 1.55 km to 2.16 km. In the main metallogenic stage, the average pressure is 67 MPa and the average depth is 1.98 km. All of the above-mentioned information indicate that the ore-forming fluid is the product of migmatization, in which the bearing-ore fluid mixed with the meteoric water in the increasing migration process. |
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