藏南扎西康整装勘查区成矿体系初探

A preliminary study of the metallogenic system in the Zhaxikang integrated exploration area, southern Tibet

扎西康整装勘查区位于青藏高原北喜马拉雅成矿带的东段,区内矿床(点)分布广泛,最著名的是扎西康铅锌锑多金属矿床,为藏南首个铅、锌、锑、银共生的大型矿床。整装勘查区内各矿床类型具有明显的空间分布规律,围绕区内南侧的错那洞淡色花岗岩体呈环带状分布:在岩体内部及其接触带主要发育高温的锡、稀有金属矿床,岩体向外逐渐发育中温脉型铅锌锑多金属矿床,远离岩体则主要出现中低温的金、锑矿床,这与1∶20万化探水系沉积物的元素异常分带性较为吻合。通过系统研究各类矿床地质特征及其时空分布规律,表明该地区成矿作用与错那洞淡色花岗岩体具有密切关系,晚期的近东西向伸展构造为本区的主要控矿构造。

The Zhaxikang integrated exploration area is located in the eastern part of the North Himalayan metallogenic belt, Tibet.The most famous deposit in this belt is the Zhaxikang polymetallic deposit, which is the first large Pb-Zn-Sb-Ag association deposit discovered in southern Tibet. Deposits and ore spots in the Zhaxikang ore district exhibit significant spatial distribution.They are all in or around the Cuonadong Granitoid Pluton（CGP）, from the internal part to the edge. The Sn and rare metals deposits formed at high temperature are mainly found in the internal part of CGP and its contact zone with the sedimentary cover. The mesothermal vein type Pb-Zn deposits are in the fault zones of sedimentary cover away from the CGP. The meso- epithermal SbAu deposits are more distant from the GCP. The distribution of deposit types are almost the same as the ore- forming element anomaly zonation determined by regional geochemical exploration of stream sediments. Based on the systematic study of the geological setting and spatial and temporal distribution of these deposits in the Zhaxikang ore district, the authors have reached the conclusion that metallogeny in the Zhaxikang ore district is closely related to CGP, and ore-controlling structures in this ore districtare mainly related to the E-W extension of the Tibetan Plateau.