地质通报2017，Vol.36Issue(10)：1800-1813,14.
滇西北格咱岛弧带南缘铜厂沟斑岩铜钼矿床花岗闪长斑岩地球化学特征、锆石U-Pb年龄及其地质意义
Geochemistry and zircon U-Pb age of the Tongchanggou porphyry Cu-Mo deposit on the southern margin of Geza arc, northwest Yunnan Province, and its geological significance
摘要
Abstract
The Geza tectonic-magmatic belt is an important part of Yidun arc and also an important ore concentration area of copper polymetallic deposits in the Sanjiang region of southwest China. Based on the study of petrologic and geochemical characteristics and zircon U-Pb geochronology of the Tongchanggou ore-forming porphyry on the southern margin of Geza arc, the authors systemati-cally analyzed the petrogenesis, tectonic environment, diagenesis and metallogenic geodynamic background of the granite. The rock type of Tongchanggou metallogenic porphyry is granodiorite porphyry, the research results of the zircon U-Pb geochronology show that the age of emplacement and crystallization of the magma is 87.62±0.59Ma(MSWD=0.52)by LA-ICP-MS method. Petrograph-ic and lithogeochemical characteristics indicate that Tongchanggou granodiorite porphyry has characteristics of high silicon ( 63.02%~74.06%), high alkali (K2O+Na2O=6.97%~8.79%), and rich K (K2O/Na2O=0.71~2.13). The rocks belong to high-K calc-alkaline rock series enriched in light rare earth elements. The fractionation between LREE and HREE is obvious. δEu values are 0.89~0.97 with a weak negative anomaly. The analytical results of trace elements show that the rocks are enriched in large ion lithophile elements of K, U, Th, Rb, Ba, Sr, and depleted in high field strength elements of Nb, Ta, P, Ti, suggesting that the formation of magma might have been derived from the partial melting of crust materials. The granite was formed in the conversion stage of post-collision and ex-tensional tectonics, belonging to the product of the collision orogenic process. The collision induced upwelling of the lithospheric man-tle which led to partial melting of the crust and formed the potassium-rich and ore-bearing initial magma. Magma rising and intrusion along the deep faults eventually triggered the late Yanshanian tectonic-magmatic and metallogenic events in Geza area.关键词
LA-ICP-MS锆石U-Pb年龄/花岗闪长斑岩/地球化学特征/成矿机制/铜厂沟/云南Key words
LA-ICP-MS zircon U-Pb age/granodiorite porphyry/lithogeochemical characteristics/mineralization mechanism/Tongchanggou/Yunnan分类
天文与地球科学引用本文复制引用
姚雪,李文昌,刘学龙,张娜,杨富成,彦廷龙,王帅帅,罗应..滇西北格咱岛弧带南缘铜厂沟斑岩铜钼矿床花岗闪长斑岩地球化学特征、锆石U-Pb年龄及其地质意义[J].地质通报,2017,36(10):1800-1813,14.基金项目
云南省科技领军人才计划项目《西南"三江"叠合成矿作用与成矿预测》(编号:2013HA001)、国家自然科学基金项目《云南格咱岛弧印支期斑岩型铜矿床变化与保存研究》(批准号:41502076)、云南省教育厅科学研究基金项目《云南格咱岛弧成矿带斑岩型铜矿成矿系统研究》(编号:2015Y066) （编号:2013HA001）
