青海牛苦头矿区两期成矿系统简析

牛苦头铅锌多金属矿床位于东昆仑造山带祁漫塔格地区中西段,目前已探明Pb+Zn资源量(推断及以上)115万t,是祁漫塔格地区最具成矿潜力的夕卡岩型铅锌矿床之一。本次研究仔细对比了牛苦头矿区M1、M4以及M2三个磁异常区的典型矿床特征,通过矿床地质特征、成矿年代学和地球化学特征、矿物组合、夕卡岩类型以及成矿构造与成矿结构面等方面,初步认为牛苦头M1、M4矿段属于海西期夕卡岩型铅锌成矿系统,M2矿段属于印支期铁多金属成矿系统。因此M2矿段可能具有铁多金属矿找矿的前景,而不具备大规模铅锌找矿的潜力。两期成矿系统的划分对于目前正在普查阶段的M2磁异常区的潜力评价工作具有重要的理论意义。

A brief analysis of the two-stage metallogenic system in Niukutou Ore district, Qinghai Province

The Niukutou Pb-Zb deposit is located in the central and western part of Qimantag area, East Kunlun orogenic belt, with a proven Pb and Zn resources of 1.15 million tons, which is one of the most potential skarn type Pb-Zn deposits in Qimantag area. Based on the comparison of geological characteristics, chronology and geochemical properties of metallogenic rock mass, mineral assemblage, skarn type, metallogenic structure and metallogenic structural plane, we preliminarily divide the Niukutou ore district into two metallogenic system: the Hercynian metallogenic system of M1 and M4 ore block and the Indosinian system of M2 ore block. In this paper, it is considered that the M2 ore block may have the potential of Fe polymetallic ore prospecting, while it does not have the potential of Pb-Zn polymetallic ore prospecting as M1 and M4 ore block. The division of the two metallogenic systems is of great theoretical signi.cance for the potential evaluation of M2 magnetic anomaly area, which is in the stage of general survey at present.