The Nongruri gold deposit is located in Gangdise-Himalaya metallogenio belt, southern Qinghai-Tibet plateau- The mineralization was strictly controlled by the SN fault. The Nongruri gold deposit is the first epithermal Au deposit discovered in the Gangdese metallogenic belt. The ore-forming age of the Nongruri gold deposit is still in dispute. In order to obtain the ore-forming age, the authors measured the sericites separated from the altered granite-porphyry which hosts the gold deposit. The Ar- Ar analyses yield weighted average age and isochron age of (19.87 ±0.96) Ma and (19.70 ±0. 30) Ma, respectively. It is held that the Au mineralization in the Nongruri deposit took place in Miocene, which is consistent with the ore-forming epoch of the porphyry copper ore deposits in the adjacent regions. This suggests that the Nongruri epithermal Au deposit, the skarn polymetallic copper deposits, and the porphyry copper ore deposits were formed in the same magma-fluid mineralization system controlled by an extensional dynamic setting in the Gangdise belt.%西藏弄如日金矿是冈底斯成矿带发现的第一个浅成低温热液型金矿床.为确定金矿床的成矿时代,对该矿床与金矿化有关的蚀变花岗斑岩中绢云母进行了40Ar-39Ar年龄测试,获得绢云母的加权平均年龄和等时线年龄分别为19.87±0.96 Ma和19.70±0.30 Ma.结果表明,弄如日金矿床金矿化的主要成矿时代为中新世.该成果的获得对于进一步认识弄如日金矿成因机制、地球动力学背景以及区域找金突破具有重要意义.
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