广东长埔锡多金属矿床石英斑岩锆石U-Pb年代学、Hf同位素组成及其地质意义  

Zircon U-Pb geochronology and Lu-Hf isotopic composition of quartz porphyry in the Changpu Sn polymetallic deposit, Guangdong Province, SE China and their geological significance

作　　者：丘增旺 王核[1] 闫庆贺[1,2] 李莎莎[1,2] 汪礼明 卜安 慕生禄 李沛[1,2] 魏小鹏[1,2] 

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [2]中国科学院大学,北京100049 [3]广东省有色金属地质局,广东广州510060 [4]广东省有色金属地质局九三一队,广东汕头515041

出　　处：《地球化学》2016年第4期374-386,共13页Geochimica

基　　金：中国地质调查局整装勘查关键基础地质研究项目(12120114015901)

摘　　要：广东省海丰县长埔锡多金属矿床位于粤东地区莲花山断裂带南西段，是一个中型锡多金属矿床。以与长埔锡多金属矿床矿化联系密切的石英斑岩为研究对象，首次对其进行了LA-ICP-MS锆石U-Pb定年以及锆石Hf同位素分析，获得其锆石U-Pb同位素加权平均年龄为（145．0±0．9）Ma，形成于早白垩世初；锆石Hf同位素特征显示其εHf（t）为-7．95--2．74，二阶段模式年龄（tDM2）为1371-1704Ma，表明石英斑岩主要来源于中元古代古老地壳岩石的部分熔融，可能有少量地幔物质的加入。根据所得数据，结合区域构造演化，长埔锡多金属矿床石英斑岩可能形成于古太平洋板块向欧亚大陆俯冲作用有关的区域伸展动力学背景。The Changpu Sn polymetallic deposit is located in the Lianhuashan Fault Belt, eastern Guangdong Province. The deposit is a medium-sized hydrothermal vein-type Sn-Pb-Zn deposit, and genetically related to quartz porphyry. In this paper, zircon U-Pb geochronology and Lu-Hf isotopic composition of quartz porphyry have been obtained for the first time. Zircon LA-ICP-MS dating of quartz porphyry yields a concordant age of （145.0±0.9） Ma, indicating the quartz porphyry was formed in the Early Cretaceous. The Hf isotopic composition of the quartz porphyry shows that the εHf（t） values vary from -7.95 to -2.74 with tDM2 ages of 1371 Ma to 1704 Ma, suggesting that the Changpu quartz porphyry probably originated from partial melting of the Mesoproterozoic ancient crustal rocks with a minor input of some mantle materials. Based on the analytical results and regional tectonic evolution, the quartz porphyry of the Changpu deposit was suggested to have been formed in a post-collision extensional tectonic setting that was triggered by the subduction of the paleo-Pacific plate.

关 键 词：锆石U—Pb年龄 HF同位素 石英斑岩 长埔锡多金属矿床 广东省 

分 类 号：P597.3[天文地球—地球化学] P588.121[天文地球—地质学]