浙江天台-嵊县地区火山岩型银（金）矿床地质地球化学特征

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	浙江天台-嵊县地区火山岩型银（金）矿床地质地球化学特征
	耿文辉
	1993
学位授予单位	中国科学院地球化学研究所
学位授予地点	中国科学院地球化学研究所
学位名称	博士
关键词	火山岩型银（金）矿地球化学浙江天文台-嵊县地区
摘要	浙江天（天台）-嵊（嵊县）地区是东南沿海中生代火山岩区Au、Ag及多金属成矿带的一部分，近年来发现多处具有工业意义的贵金属矿床。其矿床特征可以同世界上以火山岩为主岩的冰长石-绢云母型浅成低温热液贵金属矿床类比。具有高Ag、Pb、Zn（Au、Cu）丰度的前震旦纪陈蔡群变质岩和早白垩纪朝川组火山岩系是矿源层。矿床产于火山岩系中；围岩蚀变发育，硅化、绢云母化、伊利石化、菱锰矿化、冰长石化以及似青盘岩化与矿化有关。矿床元素垂直分带由浅部至深部为Au、Ag、Zn-Ag、Pb、Zn-Pb、Zn、Cu。菱锰矿的含Fe、Ca量与Ag矿化具有消长关系，菱锰矿含Fe高对Ag（Au）矿化有利。成矿流体为低盐度的NaCl-H_2O体系，富Na酸性（pH = 4.5）是该体系的特征。成矿流体来源以火山岩浆热液为主，有大气降水加入形成混合流体。硫、碳质来自火山岩浆。而成矿有用元素则来自大陆地壳的Ag、Pb、Zn （Au、Cu）高丰度值的陈蔡群或早白垩纪朝川组。成矿温度195 ℃ ～ 250 ℃及135 ℃±；成矿时代74 * 10~6年～ 105 * 10~6年，属晚白垩纪；成矿压力350 ～ 500 bar。成矿构造环境为大陆裂谷发展初期。矿床成因类型可确定为浅成中低温火山岩浆混合热液贵金属矿床。
其他摘要	The Tiantai-Shengxian area, Zhejiang province, is a part of metallogenic belt for gold、silver and base metal in the Mesozoic volcanic rock region in southeastern China. Precious metal deposits are explored in recent years, they are probably similar to volcanic - hosted precious metal deposits of altered adularia - sericite type in the world. The abundances of Ag、Pb、Zn(Au、Cu) elements are higher in Chencai Group (AnZ) and Chaochuan Group (Early Cretaceous) which could be sources of Ag、Pb、Zn etc. The deposits occurred in volcanic rocks with alteration of silicification、illitization、adularization、sericitization、rhodochrositization、pyritization and propylitization. Three mineralization zones of ore-forming elements, i.e. upper (Au, Ag, Zn), middle (Ag、Pb、Zn), lower (Pb、Zn、Cu), could be found in the ore deposits. Silver mineralization related to ferrous rhodochrosite. If the rhodochrosite contained higher Fe, the Ag mineralization was also richer. Contrarily, if it was pure or contained some Ca, the Ag could be poor. The ore-forming fluid might be NaCl-H_2O system with lower salinity, and characterized by enriched Na and acid feature (pH = 4.5). The origin of ore-forming fluid was mainly related to hydrothermal from primary volcanic-magamtio water during main ore-forming stage. But primary magmatic water and meteoric water mixed during later mineralization. Sulfur and carbon isotope data show that origin of S & C were related to the volcanic magma. The ore-forming materials (Ag、Pb、Zn、(Au、Cu)) were mainly came form Chaochuan Group or Chencai Group. The ore- forming temperature were 195 ℃ ～ 250 ℃ & 135 ℃±. Metallogenetic epoch was about 74 * 10~6 year ～ 105 * 10~6 year and the pressure around 350 bar-500 bar. Continental rift would be a better ore-forming tectonic environment. The deposits related to volcanism could be called as the type of epithermal precious metal deposit.
页数	50
语种	中文
文献类型	学位论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/3922
专题	研究生_研究生_学位论文
推荐引用方式 GB/T 7714	耿文辉. 浙江天台-嵊县地区火山岩型银（金）矿床地质地球化学特征[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,1993.