西北地质2026，Vol.59Issue(1)：79-96,18.DOI:10.12401/j.nwg.2025048
西秦岭金山金矿床成矿机制:来自毒砂和绿泥石地球化学特征的证据
Metallogenic Mechanism of Jinshan Gold Deposit in West Qinling Orogenic Belt:Evidence from Geochemical Characteristics of Arsenopyrite and Chlorite
摘要
Abstract
Arsenopyrite(Apy)and chlorite(Chl)are abundant sulfide or altered minerals in hydrothermal gold deposits,which been widely used in the inversion of the physical chemical conditions of gold mineralization.The Jinshan gold deposit in Gansu Province is located in the Xiahe-Xihe-Fengxian-Huangbaiyuan metallogenic sub-belt in the eastern section of the West Qinling metallogenic belt,with superior mineralization conditions,characterized by the development of multiple generations of arsenopyrite and chlorite.In this study,we take the various types of arsenopyrite and chlorite in ore samples from the Jinshan gold deposit as the research object.Based on the division of the three mineralization stages in Jinshan Gold deposit,using electron probes to deter-mine the major elemental composition of Apy(Apy-Ⅱ～Apy-Ⅲ)and Chl(Chl-Ⅰ～Chl-Ⅲ)at each stage,di-viding the chemical types of Chl-Ⅰ～Chl-Ⅲ,calculating the formation temperature,oxygen fugacity(lgfO2),sulfur fugacity(lgfS2),and pH value of Chl-Ⅰ～Chl-Ⅲ and Apy-Ⅱ～Apy-Ⅲ.Furthermore,analyzing the for-mation environment and physicochemical conditions of Apy and Chl at each stage,and exploring the gold min-eralization mechanism of the Jinshan gold deposit.The results indicate that the diagenetic shallow metamorphic stage of Chl-I exhibits characteristics of low temperature,low lgfO2,and low lgfS2.During the hydrothermal mineralization stage,the temperature,lgfO2,lgfS2,and pH values of Chl-Ⅱ and Apy-Ⅱ significantly increased compared to stage I,indicating the loss of a large amounts of acidic components such as CO2 in Stage II,it is speculated that there was strong fluid mixing and boiling during the hydrothermal mineralization stage.Subse-quently,during the hydrothermal mineralization stages Ⅱ～Ⅲ,boiling causes a significant decrease in tempera-ture,pressure,and S content in the fluid,promoting large-scale precipitation of Au in the form of natural gold,thereby promoting the large-scale precipitation of Au in the form of natural gold.Meanwhile,under low sulfur fugacity and neutral pH value conditions,a large amount of invisible gold was formed in arsenopyrite as Au-As like substances.关键词
成矿条件/电子探针/形成环境/沉淀机制/金山金矿Key words
metallogenic conditions/electron probe/formation environment/precipitation mechanism/Jin-shan gold deposit分类
天文与地球科学引用本文复制引用
李航,范堡程,薛仲凯,杨晓奇,罗建祥,鹿新苗..西秦岭金山金矿床成矿机制:来自毒砂和绿泥石地球化学特征的证据[J].西北地质,2026,59(1):79-96,18.基金项目
中国地质调查局项目"秦岭成矿带金矿资源潜力动态评价"(DD20220975),"全国金矿资源潜力评价"(ZD20220318)联合资助. （DD20220975）
