地质通报2016，Vol.35Issue(8)：1271-1280,10.
藏南马扎拉矿区英安岩年代学与地球化学特征及其地质意义
Geochemical characteristics, chronology and geological significance of the da- cite in the Mazhala deposit, southern Tibet
摘要
Abstract
Located in Northern Himalaya metallogenic belt, the Mazhala deposit is the most representative gold deposit in the Zhaxi⁃kang integrated exploration area. In this study,the authors carried out comprehensive researches including petrochemistry and zircon U-Pb dating analysis of the dacite in the Mazhala deposit,Comei County,southern Tibet. Chemical analyses show that the dacite is characterized by high Si (SiO2=66.86%~71.84%),low alkali (Na2O+K2O=3.79%~4.60%),low Mg (MgO=0.50%~0.94%) , strong per⁃aluminous nature (A/CNK=1.55~2.23),enrichment of LILE such as Rb,U and depletion of HFSE such as Ta, Ti and Zr. The rocks also exhibit high total REE content (∑REE=295.71×10-6~343.82×10-6),enrichment of LREE and obvious differentiation (LREE/HREE=10.5~15.22),with moderately negative Eu anomalies (δEu=0.39~0.48) and no cerium anomaly. LA-ICP-MS zircon U-Pb chronology indicates that the Mazhala dacite was emplaced at 138.2±1.6Ma, being the product of the Early Cretaceous magmatic activity. According to regional geology and related data, it is considered that the dacite was formed on the Himalayan passive conti⁃nental margin and may be a part of Comei-Bunbury large igneous province.关键词
马扎拉/英安岩/LA-ICP-MS锆石U-Pb测年/地球化学/藏南Key words
Mazhala deposit/dacite/LA-ICP-MS zircon U-Pb dating/geochemistry/southern Tibet分类
天文与地球科学引用本文复制引用
董磊,李光明,李应栩,代作文,梁维..藏南马扎拉矿区英安岩年代学与地球化学特征及其地质意义[J].地质通报,2016,35(8):1271-1280,10.基金项目
中国地质调查局基础性公益性地质矿产调查项目（编号DD20160015）和中国地质调查局成都地质调查中心青年科学基金 （）
