中文摘要：

内蒙古哈什吐矿床是新发现的钼矿床。为进一步查明哈什吐钼矿床的形成时间,首次对主要钼矿体的10件辉钼矿样品进行铼-锇同位素分析,所获铼-锇同位素模式年龄变化范围为（147.0±2.1）Ma~（149.5±2.2）Ma,加权平均值为（148.22±0.67）Ma,获得等时线年龄为（148.8±1.6）Ma,MSWD值为0.95。铼-锇同位素年代数据及野外地质证据表明,哈什吐钼矿床为晚侏罗世构造-岩浆作用及相关流体活动的产物。哈什吐钼矿床辉钼矿的w（Re）介于（0.65~2.06）×10-6,平均值为1.28×10-6,通过与区域内同时期形成的若干相似类型钼矿床的Re含量对比分析,初步推测认为哈什吐钼矿床成矿物质源区具有更偏向于壳源的特征。哈什吐斑岩型钼矿床形成时代的厘定对于提高该矿床的理论研究水平和指导隐伏金属矿床的找矿勘查工作均具有重要意义。

英文摘要：

Located in the eastern part of the southern Da Hinggan Ling Late Paleozoic orogenic belt between the Silas Wood Aaron River and the Erlian-Hegenshan structure zone,the newly discovered Hashitu ore deposit is a medium-size porphyry molybdeoum deposit occurring in east-central Inner Mongolian.The Hashitu granite porphyry and biotite granite were emplaced in the widespread Quaternary sedimentary sequence in the Hashitu mineralized area.The granite porphyry intruded into the biotite granite in a slightly later period,and the two granite intrusions made up a Yanshanian complex.The Mo mineralization occurred entirely in the two types of Mesozoic granitic intrusive rocks in stratiform,lenticular and chambered forms at large steep angles.The metallic minerals of the ores from Hashitu are mainly molybdenite and subordinately pyrite,chalcopyrite,pyrrhotite,arsenopyrite and galena,whereas the gangue mineral assemblage consists of mainly quartz,sericite and subordinately chlorite,epidote,fluorite and feldspar.Re-Os isotopic age dating of ten molybdenite separates from No.1 Mo ore body yielded an isochron age of（148.8±1.6） Ma and model ages ranging from（147.0±2.2） Ma to（149.5±2.3） Ma with an average of（148.22±0.67） Ma.As the age is in agreement with field geological evidence,the authors hold that the molybdenum was concentrated from the Mo-bearing hydrothermal fluid after the intrusion of the granite porphyry and biotite granite during the Late Jurassic period.The Re content of molybdenite is（652~2 055）×10-9,averaging 1 284×10-9.The content of Re in the Hashitu Mo deposit in comparison with the Re values of other molybdenum-bearing deposits indicates that the ore-forming materials of the Hashitu Mo deposit might have been derived mainly from the crustal source.