广东河台糜棱岩带蚀变岩型金矿床的地球化学研究 |
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引用本文:.1989.Geochemistry of the Hetai gold deposit in the altered mylonite zone[J].Mineral Deposits,8(2):61~71 |
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中文摘要:产子麇棱岩带的河台金矿是一种新的金矿类型。地质及地球化学研究表明主要控矿因素有:①矿源层(含金建造)——提供金的来源;②混合岩化及花岗岩岩浆热液作用——促使金发生活化转移;③韧性剪切带——提供了导矿通道及客矿空间。矿床形成于中温(250℃)、中深(573.5×105Pa)的条件。成矿流体富含HCO3-及CO2,并具Na+>K+>Ca2+,HCO3->C1->F->∑S,CO2>CH4的特点。介质从早到晚由中性到弱碱性,氧逸度fO2为10-37~10-39。矿床是多阶段长期演化发展的产物,区域变质作用,动力变质作用,混合岩化作用过程中变质热液起着主导作用,海西—印支期断裂重熔岩浆热液活动使金局部富集。在此认识基础上,提出了河台金矿的成矿模式。 |
中文关键词:金矿 含金建造 麇棱岩带 韧性剪切带 蚀变岩型 广东河台 |
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Geochemistry of the Hetai gold deposit in the altered mylonite zone |
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Abstract:The Hetai gold deposit is located in Yunkai Mountain of west rn Guangdong, which is an important gold prospect area in South China. Based upon a detailed study on gold-bearing formation, two types of migmatite and characteristics of the gold deposit, the authors hold that the Sinian C Formation (Zc) is the most important gold-bearing formation in this area, which provided the Hetai gold deposit with large quantities of ore materials. The regional metamorphism and basement migmatitization accompanying Yunan orogeny caused the activation and transference of gold in the gold-bearing formation. Later, a further enrichment of gold took place in the fractural-metamorphic migmatite zone during the fractural metamorphism, and the Hercynian-Indosinian granitic activities once again stimulated the activation and enrichment of gold. The muscovite pegmatite, all evolution product of the granite, is closely rela—ted to orebodies in space, time and genesis. The Sihui-Vuchuan fault and its secondary faults have been repeatedly activated since the Caledonian orogeny. In profile, the gold deposit is strictly controlled by the mylonite zone and displays obvious zoning. From the wall rock to the orebody, gold and other metallogenic elements increase gradually. The ore-forming solutions are characterized by Na+>K+>Ca2+>∑Fe>Cu2+, HCO3->Cl->F->S2- and CO2>CH4, the ore-forming temperature is 200—280℃, ore-forming pressure about 566 atm(573×105Pa),and fO210-37—10-39. Gold and major cations and anions in ore-forming solutions increase steadily from early stage to late, and the isotopic evidence demonstrates that the ore-forming solutions are mixtures of metamorphic and meteoric waters, with the participation of a little magmatic water. |
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