摘要
园岭寨钼矿是南岭地区发现的首例大型斑岩型独立钼矿床,目前查明钼金属量达20万t.矿体主要产出在园岭寨花岗斑岩与寻乌组变质岩的内外接触带中.为了揭示矿床成矿流体的成分、性质、来源和成矿物质来源,探讨矿床成矿机制,开展了详细的矿床流体包裹体和稳定同位素研究.研究表明,矿床石英脉中包裹体主要呈群、星散状随机分布或均匀分布,部分呈带状分布,一般集中在4～15μm,形态多样,主要有负晶型、椭圆形、长条形和不规则形等.包裹体类型主要有纯气或纯液相包裹体、两相型包裹体(富气包裹体、富液包裹体)、含子矿物多相包裹体、含液相CO?气液三相包裹体.成矿流体以富含Na?、Ca?、Cl-、SO?2-、H?O、CO?、H?等为特征,为CO?-H?O-NaCl(CaCl?)体系,且有较强的还原性.包裹体均一温度主要集中在170～350?C,平均值为257?C,盐度NaCleq主要集中在1.40%～12.97%,流体密度为0.687～0.973 g/cm3,平均值为0.848 g/cm3,成矿流体总体上属于贫F富Cl的中高温、中低盐度、低密度的成矿流体,且富Cu、Mo、Sb、Bi等中高温成矿金属元素,相对富Co、Ni,暗示可能与深部或地幔流体有某种联系.成矿阶段石英流体包裹体的δDV-SMOW值范围为-50.2‰～-43.5‰,δ18O水值范围为2.69‰～5.69‰,为岩浆水和天水混合作用的结果.不同金属硫化物的δ34S的变化范围为-1.5‰～1.6‰,表明硫的来源比较单一,以深源硫为主.流体不混溶(减压沸腾)和不同流体混合为园岭寨钼矿形成的主要成矿机制.
Yuanlingzhai porphyry Mo deposit is a newly discovered Mo-only deposit in the Nanling region. The Mo reserve in this deposit is estimated as 200 000 t. The mineralization developed in contact zones between the Yuanlingzhai granite porphyry and Neoproterozoic metamorphic rocks of the Xunwu Formation.In this paper, we present a detailed research on fluid inclusions and stable isotope of the deposit reveals the characteristics of ore-forming fluids and mineralization. Research on fluid inclusions in quartz veins shows that they are distributed in groups, scattered random distribution or uniform distribution with long axes of 4??15 m. The morphology of inclusions are mainly negative crystal, elliptical shape, elongated shape and irregular shape. The types of fluid inclusions include pure liquid, pure gas, two phase, three-phase inclusions containing liquid CO?, and multi-phase inclusions with daughterminerals.The liquid components of fluid inclusions are mainly Na?, Ca?, Cl??and SO?2?? and the gas components are mainly H?O, CO?, H? implying that the ore-forming fluid belongs to CO?-H?O-NaCl(CaCl?) system with strong reducibility.The homogenization temperatures of the fluid inclusions vary remarkably from 170 to 350 ?C with an average of 257 ?C. The NaCleq salinities of fluids range from 1.40% to 12.97% with an average of 6.236%. The fluid density ranges from 0.687 g/cm3 to 0.973 g/cm3with an average of 0.848 g/cm3. Therefore, the ore-forming fluid is characterized by medium to high temperature, medium to low salinity, and low density with depleted F enriched Cl. Besides, the fluid rich in Cu, Mo, Sb, Bi, etc. medium to high temperature ore-forming metallic elements, relatively rich in Co, Ni, suggests some connection with deep or mantle fluid.The DV-SMOW value of the fluid inclusion in ore-forming stages ranges from -50.2‰ to -43.5‰, and OH?O value ranges from 2.69‰ to 5.69‰, which is the result of magmatic water and meteoric water mixing action. The 34S value of metal sulfide in ores ranges from -1.5‰ to 1.6‰, showing that ore-forming materials may have been derived from the deep. Fluid immiscibility (decompression boiling) and mixing of different fluids may be the main ore-forming mechanism of Yuanlingzhai Mo deposit.
作者
魏娜
黄凡
王岩
郭唯明
韩景仪
曾载淋
曾跃
温珍连
Wei Na;Huang Fan;Wang Yan;Guo Weiming;Han Jingyi;Zeng Zailin;Zeng Yue;Wen Zhenlian(MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;School of Earth Sciences, China University of Geosciences, Wuhan 430074, China;South Jiangxi Geological Survey Party, Jiangxi Bureau of Geology and Mineral Resource Exploration and Development, Ganzhou 341000, China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2018年第S2期135-148,共14页
Earth Science
基金
国家自然科学基金项目(No.41402069)
中央级公益性科研院所基本科研业务费专项资金项目(No.K1305)
关键词
流体包裹体
微量元素
S、H、O同位素
成矿机制
园岭寨钼矿
南岭
矿床
fluid inclusions
trace elements
S, H, O isotope
ore-forming mechanism
Yuanlingzhai Mo deposit
Nanling
deposit
