青海东昆仑五龙沟矿集区金、铜多金属热液成矿作用及成矿背景研究

Wulonggou ore concentration area, located in the Eastern Kunlun Orogen, is a typical place where widespread granitic intrusions, orogenic gold deposits and skarn-type Cu polymetallic deposits occurred. There were apparent researching disequilibriums among different ore districts. Little achievement was gained in other gold ore districts such as Shenshuitan and Hongqigou where important ore-prospecting results were made in recent years. And researches for geochemical characteristics of mineral deposits in all ore districts were still obviously deficient. At the same time, there was few research for widespread Indosinian granitic intrusions that are related with Au, Cu polymetallic mineralizations. Based on field investigation, we will use LA-ICP-MS zircon U-Pb dating, petrogeochemistry and Sr, Nd, Hf isotopic researches to determine the diagenetic ages, origins, peterogenesis and tectonic significances of each type of Inosinian granitic intrusion in the Wulonggou area in this project, and discuss their ore-controlling significances for Au, Cu polymetallic mineralizations. With methods including H, O, S, Pb isotopic researches and microthermometric analyses of fluid inclusions, we will summarize geological and geochemical characteristics of all ore districts, and build evolutional models of ore-forming fluids, then judge origins of ore-forming fluids and sources of metallogenic materials. Finally, we will determine the Indosinian metallogenic geodynamic settings and their evolutional processes for the study area, and discuss genesis of mineral deposits, then build metallogenic models for the Au, Cu polymetallic deposits and summarize enriched regularities of mineralizations.

五龙沟矿集区是东昆仑造山带内一个典型的花岗质岩、造山型金矿和矽卡岩型铜多金属矿集中产出区。其内不同矿区研究程度极度不均衡，尤其是对近几年取得重大找矿突破的深水潭和红旗沟等金矿区研究极其薄弱；对所有矿区的矿床地球化学特征研究也明显不足；同时，前人对其内广泛发育的与金、铜多金属矿关系密切的印支期花岗质岩的研究也几为空白。本项目拟在野外调研基础上，通过LA-ICP-MS锆石U-Pb定年、岩石地球化学和Sr、Nd、Hf同位素研究等，确定区内各类印支期花岗质岩的成岩时代、成因、源区及构造意义，并探讨其对区内金、铜多金属矿的控矿意义；通过H、O、S、Pb同位素和流体包裹体显微测温研究等，确定各矿区的矿床地质地球化学特征，建立成矿流体演化模式，判断成矿流体和成矿物质来源。最后厘定研究区印支期成矿地球动力学背景及其演化过程，确定矿床成因，建立金矿、铜多金属矿的成矿模式，并总结矿化富集规律。

五龙沟矿集区是东昆仑造山带内一个典型的花岗质岩、造山型金矿和矽卡岩型铜多金属矿集中产出区。其内不同矿区研究程度极度不均衡，尤其是对近几年取得重大找矿突破的深水潭和红旗沟等金矿区研究极其薄弱；对金矿床地球化学特征及区内广与金、铜多金属矿关系密切的印支期花岗质岩的研究也几为空白。本项目拟在野外调研基础上，通过LA-ICP-MS锆石U-Pb定年、岩石地球化学、Hf同位素研究，H、O、S、Pb同位素和流体包裹体显微测温研究等，开展了以下研究并取得了相应成果：（1）探讨了五龙沟矿集区八路沟铜多金属矿的矿床地球化学特征研究，进一步确认了其矽卡岩型成因；（2）通过对五龙沟晚志留世和晚三叠世花岗岩年代学及岩石地球化学研究，限定了东昆仑地区原特提斯洋有关的俯冲碰撞时限；（3）通过对五龙沟地区黄龙沟花岗闪长岩年代学及岩石地球化学研究，限定了五龙沟金矿成矿年龄上限（221Ma）及相应成矿背景；（4）通过对东昆仑五龙沟矿集区中三叠世辉绿岩脉的岩石成因及构造意义研究，限定了东昆仑中三叠世的俯冲性质；（5）对五龙沟深水潭金矿的含金硫化物开展了S-Pb同位素分析以及原位微区S同位素分析等，确定了深水潭金矿的矿床地球化学特征，并初步判断了其成矿物质来源；（6）对五龙沟矿区东边洪水河铁矿区的赋矿围岩碎屑锆石年龄和Hf同位素开展了研究，限定了洪水河铁矿成矿时代不早于788Ma；其成矿背景类似于是Sturtian冰期的结束时期；（7）对洪水河铁矿区早-中三叠世洪水河花岗质侵入杂岩的年代学及岩石地球化学研究，限定了东昆仑古特提斯洋的俯冲过程。项目总共发表科技论文6篇，其中SCI检索论文3篇；即将投稿SCI检索论文1篇；指导研究生7人。