The ore-hosting intrusion of Guzhonggonglu molybdenum deposit is the fragmented silication gneissic monzogranite,and the alterations are distributed in belt.The metallogenic process can be divided into K-feldspar+quartz,quartz+molybdenite and quartz+pyrite stages.The Re-Os isotope model age of two molybdenite samples are(142.4±2.9)Ma and(142.3±2.0)Ma,respectively,indicating that the deposit was caused by the Early Cretaceous tectonic-magmatic activities.The content of Re in the molybdenite are 11.894×10-6 and 11.584×10-6,respectively,suggesting that the ore-forming materials are mainly derived from the crust,and probably affected by the mantle.The preliminary study of fluid inclusions demonstrates that the fluid inclusions in the quartz are mainly gas-liquid two phase inclusions,secondly gas-liquid-solid three phase inclusions,minor CO2-bearing three phase inclusions.The homogenization temperature of all type of inclusions are of 196.3～>450℃,while the salinities can be divided into two groups: 0.18％～12.62％and 45.33％～>53.26％.Thus,the ore-forming fluid belongs to the medium-high temperature,and high salinity NaCl-H2O-CO2 fluid system,and the fluid boiling might occur during the ore-forming stage and be the major metallogenic mechanism.Combined with the characteristics of ore-forming conditions,ore deposit geology and fluid inclusions,the study indicate that the Guzhonggonglu molybdenum deposit is of porphyry type,and formed under a regional extension tectonic settings.%古中公路钼矿床含矿岩体为碎裂硅化片麻状二长花岗岩体,蚀变呈带状分布,成矿过程可划分为钾长石+石英、石英+辉钼矿及石英+黄铁矿3个阶段.2件辉钼矿样品的Re-Os同位素模式年龄分别为(142.4±2.9)Ma和(142.3±2.0)Ma,表明矿床为早白垩世构造-岩浆活动的产物;辉钼矿中w(Re)含量分别为11.894×10-6和11.584×10-6,暗示成矿物质主要为地壳来源,可能有地幔物质的参与.流体包裹体研究表明:主成矿阶段的石英中主要以气液两相包裹体为主,其次为含子晶三相包裹体,CO2三相包裹体最少;不同类型包裹体的均一温度范围为196.3℃～>450℃,盐度可分为0.18％～12.62％和45.33％～>53.26％两个不同区间.因此,成矿流体为中高温、高盐度的NaCl-H2O-CO2体系,在热液成矿阶段可能发生过流体沸腾作用,且是钼矿的主要形成机制.综合成矿地质条件、矿床地质特征及成矿流体特征认为,该矿床成因上属斑岩型,形成于区域伸展的构造环境.
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