西北地质2026，Vol.59Issue(1)：110-129,20.DOI:10.12401/j.nwg.2025110
南秦岭老君庙金矿床载金含砷黄铁矿矿物学研究及其地质意义
Mineralogical Study of Gold-Bearing Arsenian Pyrite in the Laojunmiao Gold Deposit,South Qinling,and Its Geological Significance
摘要
Abstract
The Laojunmiao gold deposit,located between the Gongguan and Qingtongou super-large Hg-Sb de-posits,is a medium-size gold deposit recently discovered in the South Qinling Orogenic Belt.The gold mineral-ization mainly hosted in the clastic-carbonate rocks of the Upper Devonian Xichahe Formation.Controlled by stratigraphy and structure,the orebodies are distributed along the EW-trending structural fracture zone,and the mineralization is relatively concentrated at the intersection of faults.However,there is still a lack of systematic research on the distribution pattern of gold in minerals and the types of deposits.Based on field investigations,mineralogy observations,backscattered electron(BSE)imaging,and electron probe micro probe analysis(EP-MA),the compositions of the gold-bearing minerals and the occurrence state of Au in the Laojunmiao gold de-posit are determined,and the deposit's genesis was discussed.The results show that the mineralization process of the Laojunmiao gold deposit can be divided into three stages:sedimentary-diagenetic stage,hydrothermal miner-alization stage,and supergene oxidation stage.The gold mineralization during the hydrothermal stage is predom-inantly fine-grained disseminated type,which can be subdivided into three substages:Quartz+Arsenic-bearing pyrite stage(Ⅰ),Quartz+Arsenic-bearing pyrite+Arsenopyrite+Sphalerite stage(Ⅱ),and Quartz+Calcite stage(Ⅲ).Arsenic-bearing pyrite and arsenopyrite are both gold-bearing minerals,but pyrite is the primary gold-bearing mineral.Both sedimentary-stage pyrites(Py1 and Py2)and hydrothermal-stage pyrites(Py3 and Py4)contain gold.The gold content of hydrothermal-stage pyrites is significantly higher than that of sedimentary-stage pyrites,and there is a positive correlation between Au and As.Gold primarily exists as invisible gold.Au in sedimentary-stage pyrites(Py1 and Py2)occurs primarily as gold nanoparticles(Au0);while gold in hy-drothermal-stage pyrites(Py3 and Py4)and arsenopyrite(Apy)occurs as lattice gold(Au+).The results indicate that the Laojunmiao gold deposit show similargeological characteristics,metallogenic conditions,and gold oc-currence modes with typical Carlin-type gold deposits.Compared with the δFe-δS,δFe/δS-As,and(Fe+S)-As systems of various genetic types of gold deposits in China,the pyrite mineralization during the mineralization period all falls within the Carlin-type gold deposit region.Therefore,the Laojunmiao gold deposit could be clas-sified as a Carlin-type gold deposit.关键词
南秦岭/老君庙金矿/金的赋存状态/电子探针/载金硫化物/卡林型金矿Key words
South Qinling/Laojunmiao gold deposit/gold occurrence modes/electron probe microanalysis(EPMA)/gold-hosting sulfides/Carlin-type gold deposit分类
天文与地球科学引用本文复制引用
贾彬,张振,魏立勇,吴欢欢,唐明锋,孟五一,田映天,王鑫..南秦岭老君庙金矿床载金含砷黄铁矿矿物学研究及其地质意义[J].西北地质,2026,59(1):110-129,20.基金项目
自然资源综合调查指挥中心科技创新基金(KC2024007),中国地质调查局项目"南秦岭旬北地区金锑找矿靶区优选与评价"(DD20230370)联合资助. （KC2024007）
