藏北商旭金矿床控矿因素及其找矿标志

班公湖-怒江成矿带跨班公湖-怒江缝合带两侧，是近年来发现的一条重要的多金属成矿带。商旭金矿床位于班公湖一怒江缝合带中段，主要矿体呈透镜状或脉状产于中一下侏罗统木嘎岗日群浅变质海相复理石建造中，受近东西向断裂构造控制。矿石类型以石英脉型为主，其次为蚀变岩型，近矿围岩蚀变较弱，蚀变类型包括硅化、绢云母化、绿泥石化、碳酸盐化等。矿石中金属矿物主要为自然金、黄铁矿及方铅矿；脉石矿物以石英、方解石以及黏土矿物为主。初步研究表明，该矿床主要受地层及构造因素控制，成因类型为造山型金矿床。在此基础上，初步总结了矿区的主要找矿标志，包括岩性及构造标志、蚀变标志、硫化物标志、化探异常及古采矿遗迹标志等，并认为区域上存在找到商旭式金矿床的可能。

Prospecting indicator and ore-controlling factors of Shangxu gold deposit in north Tibet

Bangongco-Nujiang meteallogenic belt which spans to both sides of Bangongco-Nujiang suture belt,is one of polymetallic meteallogenic belts with huge ore potentials. Shangxu gold deposit is located in the middle part of Bangongeo-Nujiang suture belt, the main ore bodies of which occur in the low metamorphic marine elastic rocks of the middle-low Jurassic Mugagangri group as lens or veins and are mainly controlled by nearly EW faults. The major ore type is of quartz vein, and secondary of altered rock. Adjacent wall rock didnl undergo a clear hydrothermal alteration, and the main alteration type includes silieifieation, sericitization, ehloritization and carbonatization etc. Ore minerals mainly are native gold, then little of galena, pyrite, and gangue minerals mostly quartz, calcite and clay minerals. Pre- liminary research indicates that Shangxu gold deposit is mainly controlled by strata and structure. It belongs to orogenic gold deposits. Some major exploration indicators of the gold ore are summed up on the basis of the above analysis, in- eluding lithological and structural criteria, alteration criteria, sulfide mineral criteria, geochemical exploration anomaly and remains of previous mining tunnels etc. The paper proposes that it is possible to find more primary gold deposits similar to that of Shangxu in Bangongeo-Nujiang suture belt.