新疆金坝金矿床地质地球化学特征及找矿标志

Geological and Geochemical Characteristics and Prospecting Indicators of Jinba Gold Deposit in Xinjiang

金坝金矿位于西伯利亚古板块南缘阿尔泰陆源活动带克兰弧后盆地与哈巴河弧间盆地接壤处,属哈、中、蒙阿尔泰多金属成矿带的东延部分,矿体产于哈巴河斜长花岗岩内、外接触带附近,受玛尔卡库里大断裂及其次级断裂严格控制,为典型的韧性剪切带型金矿。矿石类型主要为含金石英脉型及蚀变闪长岩型,蚀变矿物主要为绿泥石、硅化、黄铁矿等。通过总结分析金坝金矿区的地质特征和地球化学特征,认为中泥盆统阿勒泰组地层为成矿提供了物质来源,华力西中期第三侵入期次的岩浆活动为成矿提供了热动力,玛尔卡库里断裂早期韧性剪切活动为成矿提供了容矿空间,矿体沿次级断裂走向呈近等距分布,具有明显的分支复合和尖灭再现现象。矿区地球化学测量共圈定5个异常区,异常呈丛集团块状、条带状断续分布,走向与区域构造线方向基本一致,也从侧面证明了矿体的产出受到断裂构造的严格控制。根据成矿规律及地质地球化学特征,建立了金坝金矿床的找矿标志,以期为矿区及其外围下一步的找矿工作提供参考。

Jinba gold deposit is located at the junction of the Kelan back-arc basin and the Habahe interarc basin in the Altai terrigenous active belt on the southern margin of the Siberian paleoplate.It belongs to the eastern extension of the Habahe,Middle Mongolia and Altai polymetallic metallogenic belt.The ore body occurs in the inner and outer contact zone of the Habahe plagioclase granite and is subjected to the Malkakuli fault and its secondary level.The fracture is strictly controlled and is a typical ductile shear zone type gold deposit.The ore types are mainly gold-bearing quartz vein type and altered diorite type.The altered minerals are chlorite,silicification,pyrite and so on.By summarizing and analyzing the geological and geochemical characteristics of Jinba gold deposit,it is concluded that the Altai Formation strata of the Middle Devonian provide the material source for mineralization,the magmatic activity of the third intrusion period of the Middle Variscan provides the thermal power for mineralization,and the ductile shear activity of the early Markakuli fault provides the ore-hosting space for mineralization.Ore bodies distribute nearly equidistantly along the strike of secondary faults,showing obvious phenomena of branching,recombination and pinch-out.Geochemical surveys in the mining area delineate five anomalous areas.The anomalies distribute in clumps and bands,and their strike is basically consistent with the direction of regional tectonic lines.It also proves that the occurrence of ore bodies is strictly controlled by fault structures.According to metallogenic regularity and geological and geochemical characteristics,the prospecting criteria of Jinba gold deposit are established in order to provide reference for the next prospecting work in the mining area and its periphery.