多尺度综合地球物理方法在扎西康铅锌锑金多金属矿找矿预测中的应用

青藏高原后碰撞阶段发生了大规模地壳尺度的伸展作用,并在特提斯喜马拉雅带内发育了淡色花岗岩、南北及东西向断裂等构造-热事件,形成了一系列的铅锌锑金多金属矿床.扎西康铅锌锑金多金属矿是带内已发现唯一的超大型多金属矿床.应用多尺度的综合地球物理方法开展扎西康矿区的找矿预测,为特提斯喜马拉雅铅锌锑金成矿带内的矿床勘查提供借鉴.首先,通过穿越错那洞穹窿、藏南拆离系(STDS)及扎西康典型矿床的南北向MT剖面(长72 km,基准点距1 km),初步建立了扎西康矿床深部构造-热事件的空间关系,结合区域构造-热事件的时间关系,提出了构造-热耦合成矿作用模型,为扎西康的地球物理勘探提供基础.其次,通过1∶5万区域重力(线距500 m,点距400 m)和MT剖面(点距500 m)浅部信息的联合解译,对扎西康整装勘查区尺度的导矿构造开展研究.最终,通过激电中梯扫面测量(线距100 m,点距40 m)、AMT剖面(点距50 m)及重力剖面(点距20 m)的联合解译,对扎西康的含矿断裂开展研究,定位深部隐伏矿体.

Application of Multi-Scale Integrated Geophysical Method in Prospecting Prediction of Zhaxikang Pb-Zn-Sb-Au Polymetallic Deposit

A crustal scale extension occurred in the post-collisional stage of the Tibetan Plateau, and tectonic-thermal events closely related to stretching, such as leucogranites, north-south and east-west faults, were developed in the Tethyan Himalayan and developed series of Pb-Zn-Sb-Au polymetallic deposits. The Zhaxikang Pb-Zn-Sb-Au polymetallic deposit is the only superlarge polymetallic deposit in the belt. This paper applies a multi-scale integrated geophysical method to Zhaxikang's prospecting prediction and can provide reference for the exploration of deposits in the Tethys Himalayan Pb-Zn-Sb-Au metallogenic belt. Firstly, the spatial relationship of tectonic-thermal events was initially established by the north-south MT section (72 km long and 1 km from the reference point) crossing the Cuonadong dome and the South Tibet detachment system (STDS). Combined with the time relationship of regional tectonic-thermal events, a possible tectonic-thermal coupling mineralization was proposed, which provides a basis for the geophysical exploration of Zhaxikang. Secondly, through the joint interpretation of 400 km2, 1:50 000 regional gravity (line distance 500 m, dot distance 400 m) and MT(dot distance 400 m) shallow information, the fault system of the Zhaxiang assembly area was established. Finally, the Zhaxikang polymetallic ore body was delineated by the joint interpretation of the 9 km2 IP measurement (line distance 100 m, dot distance 40 m) and the AMT profile(dot distance 50 m) and gravity(dot distance 20 m).