安徽大别山地区沙坪沟超大型斑岩钼矿床成矿系统特征  

Characteristics of the metallogenic system of the Shapinggou super-large porphyry molybdenum deposit in the Dabie orogenic belt,Anhui Province

作　　者：任志[1,2] 周涛发 袁峰[1,3] 张怀东 REN Zhi;ZHOU Taofa;YUAN Feng;ZHANG Huaidong(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;Anhui Mineral Resources and Mine Environmental Engineering Research Center,Hefei 230009,China;No.313 Geological Party,Anhui Bureau of Geology and Mineral Exploration,Lu'an237271,Chin)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009 [2]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [3]安徽省矿产资源与矿山环境工程技术研究中心,安徽合肥230009 [4]安徽省地质矿产勘查局313地质队,安徽六安237271

出　　处：《地学前缘》2020年第2期353-372,共20页Earth Science Frontiers

基　　金：国家重点研发计划项目(2016YFC0600206);国家自然科学基金项目(41872081,41320104003);中国地调局地质大调查项目(1212011220243);东华理工大学专项经费项目(DHBK2019315)。

摘　　要：东秦岭-大别钼成矿带斑岩钼矿床的成矿地球动力学、地球化学背景和成岩成矿机制等备受研究学者的重视,但仍有许多成矿学问题需要加强研究,特别是超大型钼矿床成矿系统的组成特征、形成与演化等还需要加以系统总结。本文以翟裕生院士的成矿系统理论为指导,选取具有代表性的沙坪沟斑岩钼矿床作为研究对象,在总结前人研究成果和作者前期工作的基础上,归纳沙坪沟钼矿床地质特征,分析成矿系统的构成,通过综合对比研究,提取系统成矿特色。沙坪沟钼矿床形成于陆内伸展环境,是中国东部中生代大规模岩浆-成矿事件的产物,其含矿斑岩起源于古老下地壳+大别杂岩+岩石圈地幔,钼主要源自古老下地壳+大别杂岩,岩浆演化与热液活动持续了约24 Ma,形成了一个直径约为3 km左右的球状巨型斑岩钼成矿系统。成矿流体经历了由早期的高温、中盐度、较高氧逸度、低碱度、低pH值、低密度,中期的中高温-中温、低盐度与高盐度共存、低密度与高密度共存、低氧逸度、富CO2,向晚期的低温、低盐度、贫CO2、较高氧逸度、较高碱度、较高pH值、较高密度进行演化的过程,含Cl络合物由于温度、氧逸度下降和流体沸腾产生的相分离导致Mo的沉淀,形成了巨量钼金属的聚集。与国内外主要的斑岩钼成矿系统相比,沙坪沟钼矿床的成矿系统具有单矿体、巨系统、先天富、长孕育、多来源、高演化、多期次、超富集等鲜明的成矿特色。应用成矿系统理论,不断深入研究这一世界级超大型高品位斑岩型钼矿床的成矿作用和成矿过程,对于全面揭示斑岩型钼矿床的成因以及同类矿床的找寻都具有十分重要的意义。The ore-forming geodynamics,geochemical background,diagenesis,and mineralization mechanism of the porphyry molybdenum deposit in the East Qinling-Dabie molybdenum metallogenic belt have attracted the attention of researchers,but some mineralization problems still need to be addressed.In particular,the composition,formation,and evolution of the ore-forming system of the super-large molybdenum deposits need to be systematically summarized.Based on the theory on metallogenic systems of academician Zhai Yusheng,this paper selects the representative Shapinggou porphyry molybdenum deposit as the research object,and summarizes its geological characteristics on the basis of previous research results and the author’s preliminary work.The composition of the ore-forming system is analyzed and the distinguishing features of the system are identified through comparative research.The Shapinggou molybdenum deposit formed in the intracontinental extensional environment and is the product of the large-scale magmatic-mineralization events of the Mesozoic in Eastern China.Its ore-bearing porphyry originated from the ancient lower crust+Dabie complex+lithospheric mantle.Molybdenum mainly originated from the ancient lower crust+Dabie complex.Magma evolution and hydrothermal activity lasted approximately 24 Ma,forming a spherical giant porphyry molybdenum ore-forming system with a diameter of approximately 3 km.Ore-forming fluids have experienced early high temperature,medium salinity,higher oxygen fugacity,low alkalinity,low pH,low density,medium-term high temperature-medium temperature,low salinity-high salinity coexistence,low density-high density coexistence,low oxygen fugacity,rich CO2,evolution to late low temperature,low salinity,poor CO2,higher oxygen fugacity,higher alkalinity,higher pH,and higher density,including Cl.The precipitation of Mo due to phase separation caused by temperature,oxygen fugacity,and fluid boiling resulted in the formation of a large amount of molybdenum metal.Compared with the main porphyry molybdenu

关 键 词：成矿系统 成矿特色 矿床地质特征 斑岩钼矿床 沙坪沟 大别山地区 

分 类 号：P618.65[天文地球—矿床学] P611.1[天文地球—地质学]