摘要
内蒙古西乌珠穆沁旗花敖包特银铅锌矿床作为一处大型矿床,相较于区域内其他大中型银铅锌多金属矿床,现有成果对该矿床的成因机制及成矿作用过程尚未形成统一认识,争议问题突出。本文在系统梳理该矿床地质特征、开展矿物学与矿相学精细研究的基础上,重点针对贯穿成矿作用的核心矿物黄铁矿的微量元素组成,以及系列金属硫化物的硫同位素特征展开专题研究,旨在为厘清矿床成矿过程提供关键地球化学约束。结果显示,黄铁矿δ^(34)S的值变化较大,在-0.87‰~+5.83‰之间,且呈现一定的升高趋势,与成矿作用相关的黄铁矿δ^(34)S的值明显高于围岩中的黄铁矿。此外闪锌矿的δ^(34)S值为+1.20‰~+4.88‰,方铅矿的δ^(34)S的值为+0.26‰~+2.41‰。黄铁矿的微量元素特征显示,成矿早期的黄铁矿(Py1)亏损As、Pb和Au,主成矿期的黄铁矿(Py2)富集As、Sb和Ag,而成矿晚期的黄铁矿(Py3)Sb和Ag相对亏损,而Au则呈现出富集的趋势。结合黄铁矿的硫同位素和微量元素变化特点,表明矿床的成矿物质来源从简单到复杂,且具有成矿早期、中期和晚期多期次沉淀特征和流体混合的特征。综合区域成岩成矿活动和矿区地质特征,认为花敖包特银铅锌多金属矿床属于浅成低温热液矿床,形成于早白垩世区域岩石圈伸展背景之下,流体混合作用是矿床沉淀的主要原因。
The Hua'aobaote Ag-Pb-Zn Deposit,located in Xi Ujimqin Banner,Inner Mongolia,is a large-scale polymetallic deposit.Compared with other large and medium-sized Ag-Pb-Zn polymetallic deposits in the region,no unified understanding has been formed regarding its genetic mechanism and mineralization process in existing studies,with prominent controversial issues.Based on systematically summarizing the geological characteristics of the deposit and conducting detailed mineralogical and mineralographic studies,this study focuses on investigating the trace element compositions of pyrite(the core mineral throughout the mineralization process)and the sulfur isotopic characteristics of a series of metal sulfides,aiming to provide key geochemical constraints for clarifying the ore-forming process of the deposit.The results indicate that theδ^(34)S values of pyrite vary greatly,ranging from-0.87‰to+5.83‰,and exhibit a certain upward trend;theδ^(34)S values of pyrite related to mineralization are significantly higher than those of pyrite in the surrounding rocks.Additionally,theδ^(34)S val-ues of sphalerite range from+1.20‰to+4.88‰,and those of galena range from+0.26‰to+2.41‰.The trace element characteristics of pyrite reveal that the early-mineralization pyrite(Py1)is depleted in As,Pb,and Au,main-mineralization pyrite(Py2)is enriched in As,Sb,and Ag.In contrast,the late-mineralization pyrite(Py3)is relatively depleted in Sb and Ag but exhibits an enrichment trend in Au.Combined with the variations in sulfur isotopes and trace elements of pyrite,it is indicated that the ore-forming material sources of the deposit evolved from simple to complex,and the deposit exhibits multi-stage precipitation(early,middle,and late mineralization stages)and fluid mixing characteristics.Considering regional diagenetic and mineralization activities as well as the geological characteristics of the mining area,it is concluded that the Hua'aobaote Ag-Pb-Zn Polymetallic Deposit is an epithermal deposit,which formed under the background of regional lithospheric extension in the Early Cretaceous,and fluid mixing is the main cause of ore deposition.
作者
刘杰
唐甘宇
陈赛
李霖龙
赖勇
LIU Jie;TANG Ganyu;CHEN Sai;LI Linlong;LAI Yong(Key Laboratory of Orogenic Belts and Crustal Evolution(Ministry of Education),Peking University,Beijing 100871,China)
出处
《现代地质》
北大核心
2025年第6期1483-1495,共13页
Geoscience
基金
国家自然科学基金项目(42192500、42192503)。
关键词
硫同位素
微量元素
成矿作用
花敖包特矿床
sulfur isotope
trace element
mineralization
Hua'aobaote Ag-Pb-Zn deposit
