Title河南嵩县纸房钼矿床流体包裹体研究及矿床成因
Other TitlesFluid Inclusion constraints on the origin of Zhifang Mo deposit Songxian county, Henan provine
Authors邓小华
李文博
李诺
糜梅
张颖
Affiliation北京大学造山带与地壳演化教育部重点实验室,北京,100871
南京大学内生金属矿床成矿机制研究国家重点实验室,南京,210093
北京大学造山带与地壳演化教育部重点实验室,北京,100871
中国科学院广州地球化学研究所成矿动力学重点实验室,广州,510640
Keywords纸房钼矿床 矿床地质 流体包裹体 造山型钼矿 秦岭造山带
Zhifang Mo deposit
Ore geology
Fluid inclusion
Orogenic Mo deposit
Qinling orogen
Issue Date2008
Publisher岩石学报
Citation岩石学报.2008,24,(9),2133-2148.
Abstract河南嵩县纸房钼矿床位于秦岭造山带北部的熊耳地体,矿体以石英脉形式产于熊耳群火山岩,并受熊耳地体南边界断裂马超营断裂的次级断裂构造控制.成矿过程包括早、中、晚三个阶段,分别以石英-黄铁矿、石英-多金属硫化物和石英-碳酸盐组合为标志,早阶段石英脉或矿物组合遭受了构造变形和角砾岩化.早、中阶段的石英中可见CO2-H2O型、NaCl-H2O型及含子晶型等3类流体包裹体,而晚阶段碳酸盐只发育NaCl-H2O型包裹体.早、中、晚阶段的流体包裹体均一温度分别为467~380℃、360~250℃和240~137℃,从早到晚逐渐降低;早、中、晚3个阶段流体包裹体盐度分别为0.18%~13.13%NaCl,eqv、0.01%~20.70%NaCl.eqv和0.35%~12.85%NaCl.eqv,早、中阶段含子晶包裹体的盐度为28.04%~31.35%NaCl. eqv.早阶段含子晶包裹体系捕获的不饱和溶液,中阶段含子晶包裹体既捕获自过饱和溶液,也捕获自不饱和溶液.早、中阶段的流体包裹体均一压力集中在180~220MPa和40~80MPa两个范围,表明成矿流体是在6km~8km深处交替于静岩和静水压力体系之间的流体系统;晚阶段流体包裹体均一压力为50~80MPa,代表张性构造内充填的静水压力流体.静岩和静水压体系之间的振荡性交替现象,与针对造山型金矿建立的断层阀模型吻合,是振荡性流体沸腾或同震愈合-破裂的结果.沸腾导致的CO2等挥发组分的逃逸使流体浓缩甚至过饱和,增高了流体的pH值和还原性,促进辉钼矿等成矿物质快速沉淀.总之,纸房钼矿床是陆陆碰撞体制发育的造山型成矿系统.考虑到早、中阶段石英中多数流体包裹体均一至气相,预测现行勘探深度之下具有较大的寻找高品位钼矿床的潜力.
The Zhifang Mo deposit in Songxian County, Henan Province is located in the Xiong'er Terrane in northern Qinling orogen. Its orebodies, occurring as quartz-veins, are hosted in volcanic rocks of the Xiong' er Group and controlled by subsidiary faults of the Machaying fault which is the south boundary fault of the Xiong' er terrane. Three stages of hydrothermal ore-forming process are recognized, Early, Middle and Late, characterized by quartz-pyrite, quartz-sulfides and carbonates, respectively. The early-stage quartz-veins or mineral assemblages are structurally deformed and brecciated. Three types of fluid inclusions, i.e. CO(2)-H(2)O, H(2)O-NaCl and daughter mineral-bearing, are observed in quartz-crystals formed in early and middle stages; while the late-stage calcites only contain H(2)O-NaCl inclusions. From early to late stages, homogeneous temperatures of fluid inclusions decrease from 467 similar to 380 degrees C (E), through 360 similar to 250 degrees C (M), to 240 similar to 137 degrees C (L); salinities change from 0.18% similar to 13.13% NaCl. eqv (E), through 0.01% similar to 20.70% NaCl. eqv (M), to 0.35% similar to 12.85% NaCl. eqv (L). Salinities of the daughter crystal-bearing fluid inclusions which only occur in early and middle stages range from 28.04 to 31.35% NaCl. eqv. The early-stage daughter crystal-bearing fluid inclusions were captured from undersaturated solution, and those of middle-stage were captured from both oversaturated and undersaturated solutions. Homogeneous pressures of fluid inclusions of the early and middle stages cluster into two groups of 180 similar to 220 MPa and 40 similar to 80 MPa, respectively, implying that fluid-systems alternated between hydrostatic and lithostatic at the depth of 6km similar to 8km. Homogeneous pressures of late-stage fluid inclusions range 50 similar to 80 MPa, suggesting an open-space filling hydrostatic fluid-system. The alternating hydrostatic-lithostatic fluid-systems, analogous to the fault-valve model established for orogenie-type gold deposits, resulted from oscillating fluid-boiling and/or coseismic broken and healing. Boiling-related escape of volatile such as CO(2) made the fluids condensed or oversaturated and elevated the fluids' pH value and reducibility, resulting rapid precipitation of ore-forming materials such as MoS(2). Therefore, the Zhifang Mo deposit can be genetically assigned to be orogenic-type ore-system formed during intercontinental collision regime. Considering that most fluid inclusions within quartz crystals formed in the early and middle stages are homogenized into gas-phase, the space beneath the current prospecting level is potential for high-grade Mo-ores.
URIhttp://hdl.handle.net/20.500.11897/266368
ISSN1000-0569
IndexedSCI(E)
中文核心期刊要目总览(PKU)
中国科技核心期刊(ISTIC)
中国科学引文数据库(CSCD)
Appears in Collections:造山带与地壳演化教育部重点实验室

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