中国地质2026，Vol.53Issue(1)：36-59,24.DOI:10.12029/gc20241217002
四川盆地东南缘洞子沟铅锌矿床成因机制——来自流体包裹体、C-H-O和Rb-Sr同位素的证据
Genesis of the Dongzigou Pb-Zn deposit in the southeast margin of Sichuan Basin:Evidence from fluid inclusions,Rb-Sr and C-H-O isotopes
摘要
Abstract
This paper is the result of mineral exploration engineering. [Objective]The Dongzigou lead-zinc deposit is located in the Sangmuchang lead-zinc metallogenic belt on the southeastern margin of the Sichuan Basin,and it is a representative lead-zinc deposit rich in organic matter within this metallogenic belt.In this paper,by investigating the properties and evolution process of the metallogenic fluid of this deposit and combining with the Rb-Sr dating results of sphalerite,a lead-zinc metallogenic model will be established,which will further improve the metallogenesis of lead-zinc resources rich in organic matter around the basin.[Methods]Based on detailed studies on basic geological characteristics and mineralogy,this paper conducts petrographic observations of fluid inclusions,microthermometric measurements of fluid inclusions and Raman spectroscopy tests.Combined with the characteristics of C-H-O isotope compositions and the isochron ages of Rb-Sr isotopes of sphalerite,it clarifies the lead-zinc metallogenic process and establishes the metallogenic model.[Results]Petrography of fluid inclusions shows that fluid inclusions in the main metallogenic stage are mainly liquid-rich inclusions(LV).Combined with laser Raman analysis,it indicates that the metallogenic fluid belongs to the NaCl-H2O system.The results of microthermometry demonstrate that the metallogenic fluid is generally of medium-low temperature,medium-low salinity and medium-low density.The characteristics of C-H-O isotope compositions suggest that the metallogenic fluid is closely related to marine carbonate rocks.In the early stage,the metallogenic fluid is mainly formation water,and in the middle and late stages,meteoric water is mixed in.Moreover,carbonate rock dissolution occurred during the metallogenic process.The isochron diagram of 87Rb/86Sr-87Sr/86Sr isotopes of sphalerite shows that the isochron age of the Dongzigou deposit is(135.2±6.1)Ma with MSWD=1.10.[Conclusions]The lead-zinc precipitation mechanism of this deposit is dominated by the non-isothermal mixing of ore-forming fluids and meteoric water.The Yanshanian tectonic uplift not only provided favorable ore-conducting and ore-hosting spaces for the deposit,but also drove the migration of ore-forming fluids and their mixing with meteoric water.This process further reduced the solubility of lead and zinc in the fluids,thereby facilitating the precipitation and enrichment of lead-zinc minerals.关键词
成矿流体特征/C-H-O同位素/闪锌矿Rb-Sr定年/铅锌成矿模式/四川盆地东南缘/贵州省/矿产勘查工程Key words
metallogenic fluid characteristics/C-H-O isotopes/Rb-Sr dating of sphalerite/lead-zinc metallogenic model/southeastern margin of Sichuan Basin/Guizhou Province/mineral exploration engineering分类
天文与地球科学引用本文复制引用
辜鹰,张海军,陈翠华,李智武,陈晨,黄小东,黄定炜,尹力..四川盆地东南缘洞子沟铅锌矿床成因机制——来自流体包裹体、C-H-O和Rb-Sr同位素的证据[J].中国地质,2026,53(1):36-59,24.基金项目
国家自然科学基金项目(41372093)、四川省科技厅自然科学基金项目(2023NSFSC0274)与成都工业学院人才项目(2024RC33)联合资助. Supported by the National Natural Science Foundation of China(No.41372093),Natural Science Foundation of Sichuan Province(No.2023NSFSC0274)and Talent Project of Chengdu Technological University(No.2024RC33). （41372093）
