德新银铅锌矿床位于拉萨地块中部隆格尔-工布江达断隆带中段,是冈底斯银铅锌多金属成矿带上典型的热液型矿床之一.区内的铅锌矿化主要赋存于围岩裂隙和花岗斑岩中.利用LA-ICP-MS锆石U-Pb测年方法对区内含矿花岗斑岩进行年龄测定,获得206Pb/238U年龄加权平均值为57.7±0.5Ma(MSWD=1.6,n=15),代表花岗斑岩及与之相关的铅锌矿化形成年龄.综合区域地质背景,认为德新矿区与花岗斑岩有关的铅锌矿化形成于印度-亚洲大陆主碰撞时期,与纳如松多隐爆角砾岩型铅锌矿属同一岩浆成矿系统,冈底斯中西段存在(近)主碰撞阶段成矿事件.%The Dexin Ag-Pb-Zn deposit, located in the Longgeer-Gongbujiangda fault-block uplift belt at the center of Lhasa Ter?rane, is one of the representative hydrothermal type deposits in the Gangdise Ag-Pb-Zn polymetallic ore-forming belt. The Pb-Zn mineralization dominantly occurs in the fractures of wall rocks and the granitic porphyries. Zircons from the ore-bearing granitic por?phyry in Dexin were measured by the LA-ICP-MS U-Pb dating method, which yielded a weighted average 206Pb/238U age of 57.7± 0.5Ma (MSWD=1.6, n=15) that represents the formation age of the granitic porphyries and the Pb-Zn mineralization in the granitic porphyries. With a comprehensive analysis of geological background, it is concluded that the Pb-Zn mineralization associated with the granitic porphyries in Dexin and the cryptoexplosive breccia type Pb-Zn mineralization in Narusongduo were formed by the same magmatic metallogenic system, and there were many magmatic-metallogenic events near/in the main Indian-Asian collisional period in the mid-west part of Gangdise.
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