西藏玉龙铜矿带包买矿床含矿斑岩锆石U-Pb年代学

包买斑岩型铜钼矿床是西藏玉龙铜矿带北段重要组成部分，具有典型的斑岩型矿化、蚀变特征.最新勘查进展揭示其铜、钼资源量均已达中型矿床规模，但理论研究工作仍十分薄弱.以矿区基本地质特征为基础，运用LA-ICP-MS锆石U-Pb年代学方法，精确获得包买矿区与成矿有关的黑云母花岗岩和黑云母二长花岗岩侵位时代分别为:41.3±0.2 Ma和40.8±0.2 Ma，与玉龙、扎那尕等矿床一致，是始新世印度大陆与欧亚大陆碰撞造山过程的产物.综合区域已有年代学证据，玉龙铜矿带与成矿有关的斑岩体主要集中侵位于37~42 Ma，可能不存在明显的早（51 Ma）、中（41 Ma）、晚（33 Ma）三期，且从北西向南东，成岩成矿时代也没有明显降低变新的趋势. 

Zircon U-Pb Geochronology of Ore-Bearing Porphyries in Baomai Deposit,Yulong Copper Belt,Tibet

Baomai porphyry copper-molybdenite deposit is an important part of the northern Yulong copper belt, Tibet, with typical porphyry-type mineralization and alteration. The latest exploration shows that both Cu and Mo resources have reached the medium-sized deposit, but the research work is still very poor. Based on the basic geological characteristics, intrusion ages of biotite granite porphyry and biotit-monzogranite are 41.3±0.2 Ma and 40.8±0.2 Ma, respectively, according to the LA-ICP-MS zircon U-Pb geochronology method. These results are consistent with those of Yulong and Zhanaga deposits. All of them are the products of continent collision orogeny of India with Eurasia in Eocene. Geochronology evidences show that porphyries related to mineralization in the Yulong copper belt are mainly intruded at 37-42 Ma, and no obviously early (51 Ma), medium (41 Ma) and late (33 Ma) stages magmatic activities. From northwest to southeast, the ages of diagenesis and mineralization in Yulong copper belt do not change to be younger significantly.