扬子陆块西缘江浪穹窿及“里伍式”富铜矿床研究进展与问题-《地球科学与环境学报》

文章信息/Info

Title:: Review on Jianglang Dome and Liwu-type Cu-rich Deposit in the Western Margin of Yangtze Block

作者:: 代堰锫; 张惠华; 朱玉娣; 沈战武; 李同柱; 马东; 1.中国地质调查局成都地质调查中心，四川成都 610081；2.西南石油大学地球科学与技术学院，四川成都 610500

Author(s):: DAI Yan-pei; ZHANG Hui-hua; ZHU Yu-di; SHEN Zhan-wu; LI Tong-zhu; MA Dong; 1. Chengdu Center, China Geological Survey, Chengdu 610081, Sichuan, China; 2. School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, Sichuan, China

Keywords:: metamorphic core complex; formation age of strata; metamorphosed basement; mineralization age; genesis of mineral deposit; Cu deposit; Jianglang dome; Yangtze Block

摘要:: 江浪穹窿位于扬子陆块西缘，以发育“里伍式”富铜矿床而著称。在总结江浪变质核杂岩、矿源层、成矿时代、构造变形与成矿关系等研究成果的基础上，认为对副变质岩及变基性岩夹层进行锆石U-Pb定年，可精确厘定里伍岩群、江浪岩组与甲坝岩组地层时代，进而查明江浪穹窿是否发育古老(太古宙—古元古代)变质基底；利用⁴⁰Ar/³⁹Ar热年代学对顺层韧性剪切带(略早于成穹作用)中黑云母与重力下滑褶皱(成穹作用后期)中绢云母进行定年，可限定江浪穹窿成穹时代；“里伍式”富铜矿床属中高温热液脉状铜矿床，其基本地质特征、成矿流体性质与造山型矿床相似；采用Rb-Sr(黄铜矿)、Re-Os(黄铜矿与磁黄铁矿)、U-Pb(含矿石英脉中热液锆石)以及Sm-Nd(矿化蚀变带中石榴石)同位素定年方法，能够获取可靠的成矿年龄。因此，正确应用现代先进测试技术有助于解决江浪穹窿及“里伍式”富铜矿床重要地质问题。此外，加强扬子陆块西缘穹窿之间的对比研究，对区域找矿工作非常有意义。

Abstract:: Jianglang dome is located in the western margin of Yangtze Block, and is famous for the occurrences of Liwu-type Cu-rich deposit. Jianglang metamorphic core complex, source bed, mineralization age and the relationship between structural deformation and mineralization were summarized. The results show that zircon U-Pb dating on para metamorphic rocks and metabasalts can determine the formation ages of Liwu Group, Jianglangyan Formation and Jiabayan Formation, through which the existence of Archean or Paleoproterozoic metamorphosed basements could be ascertained; ⁴⁰Ar/³⁹Ar dating on biotite in the bedding ductile shear zone (pre-doming) and sericite in the gravity gliding folds (the later stage of doming) can constrain the timing of doming; Liwu-type Cu-rich deposit is medium-high hydrothermal veined Cu deposit, with the geological features and ore-forming fluid signatures similar to those of orogenic deposits; the mineralization ages are reliable by means of Rb-Sr (chalcopyrite), Re-Os (chalcopyrite and pyrrhotite), U-Pb (hydrothermal zircons in ore-bearing quartz veins) and Sm-Nd (garnet in mineralization belts) isotopic dating. Therefore, the applications of advanced measuring techniques are helpful to settle the key geological problems of Jianglang dome and Liwu-type Cu-rich deposits. Moreover, the comparative studies on domes in the western margin of Yangtze Block are apparently beneficial to regional prospecting.