红花尔基钨多金属矿是近年在大兴安岭中北部地区发现的一处大型钨多金属矿床,主要矿化蚀变为云英岩化、绢英岩化,主要有用金属矿物为白钨矿和辉钼矿,岩体内辉钼矿与白钨矿有上钼下钨的带状分布特点,地质特征显示该矿床为一高温热液型钨(钼)矿床.为准确限定成矿热液活动时间,本文对矿区典型蚀变矿物——云英岩化蚀变带白云母进行 Ar - Ar 同位素定年,获得 Ar - Ar 坪年龄为 174. 4 ± 1. 2 Ma,等时线年龄为 173. 2 ± 4. 3 Ma.根据矿区云英岩化带与钨钼矿化带空间上重合和密切共生的关系,可知白云母的形成是与白钨矿、辉钼矿形成同源、同时,且辉钼矿 Re - Os 年龄(176. 8 ± 2. 2 Ma)与 Ar - Ar 年龄在误差范围内具有一致性,该年龄代表了钨钼矿热液成矿时代.结合野外地质特征及锆石 U - Pb、辉钼矿 Re - Os年龄,进一步限定该矿床成矿时代为早中侏罗世,属燕山期构造岩浆活动的产物.%The newly found Honghuaerji tungsten polymetallic deposit is a large scale tungsten deposit in north-east Daxinganling in China. The alteration includes sericitization and greisenization. The metallic minerals are scheelite and molybdenite. These minerals in rock body show the belt characteristics of W in the top and Mo in the bottom. Geological characteristics indicate that it is a high temperature hydrothermal deposit. In order to constrain the timing of hydrothermal activities,Ar-Ar dating of muscovite from the greisenization alteration zones was carried out. The Ar-Ar dating yields an Ar-Ar plateau age of 174. 4 ± 1. 2 Ma and an isochron age of 173. 2 ± 4. 3 Ma. Because greisenization alteration zones and the tungsten( molybdenum)mineralization belt are closely related in space, muscovite,scheelite,and molybdenite may have formed simultaneously. Moreover,the Ar-Ar age of muscovite is in agreement with the Re-Os age of molybdenite(176. 8 ± 2. 2 Ma)within uncertainties,indicating this Ar-Ar age represents the timing of the tungsten and molybdenum hydrothermal mineralization. Combined field geology,U-Pb ages and Re-Os ages indicate this deposit formed the Jurassic period and may be the product of Yanshanian tectonic magmatic activity.
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