摘要
海南省西部土外山、抱板、二甲、不磨等金矿床是产于变质碎屑岩中受戈枕剪切带控制的蚀变糜棱岩型金矿。对这些典型金矿床中的石英和方解石所含流体包裹体的镜下观察，均一温度、盐度和成分以及Ｈ、Ｏ同位素的测试，并结合对成矿地质、构造背景的研究得出：成矿流体具有混合热液特点，δ１８Ｏ和δＤ值分别为－１０．４‰－－４．７‰和－５０‰－－８７‰；热液成分为Ｎａ＋（Ｋ＋）－Ｃａ２＋－Ｃｌ－（Ｆ－）型；Ａｕ的成矿温度主要为２４０－２５０℃；成矿流体的盐度为２．０％－９．２％（ＮａＣｌ）；成矿压力为２７－５０ＭＰａ。成矿流体的性质和成分在时间上和空间上都有一定的变化，受构造演化和构造不同部位的控制，并与其来源有关。
The gold deposits of Tuwaishan, Baoban, Erjia, Bumo, etc. in western Hainan occur in Precambrian metamorphic clastic rocks and their distributions are controlled by Gezhen shear zone. Fluid inclusion studies have been carried out. The homogenization temperatures of the fluid inclusions range from 140℃ to 370℃ and gold mainly precipitated at 240℃ to 250℃. Their salinities range from 2.o%-9.2% NaCl equiv. and the pressure of formation of the deposits is about 27-50 MPa,corresponding to a depth of about 1.1-2.0 km. The chemical compositions of inclusions show that the ore-forming fluid is the Na￣+(K￣+)-Ca￣(2+)-CI￣-(F￣-) type. The values of δ￣(18)O and δD for the fluid vary mainly from -10.4‰ to 4.7‰ and from-50‰ to-87‰. The evidences obtained from fluid inclusions and geological setting indicate that the ore-forming fluid is mainly a mixture fluid of magmatic hydrothermal fluid and meteoric hydrothermal fluid. The chemical compositions and the values of δ￣(18)O and δD changed with the ore-forming processes and different ore-fields, which was closely related to regional structural movement, metamorphism and magmatism.
出处
《地球化学》
CAS
CSCD
北大核心
1995年第C00期160-167,共8页
Geochimica
基金
中国科学院"八五"重大科研项目
中国科学院矿床地球化学开放研究实验室基金
