摘要:
铲子坪金矿位于雪峰山构造岩浆岩带的白马山复式花岗岩体外接触带附近。本文通过对铲子坪金矿床岩石地球化学以及稳定同位素的研究,探讨其矿床成矿物质来源及矿床成因。研究结果表明:矿石中金属硫化物的δ34S介于-7.58‰~+0.32‰,平均为-2.44‰,富轻硫,表明硫化物中的硫主要来自花岗岩浆,有部分地层硫酸盐中的硫混入;铅同位素组成相对稳定,变化范围很小。根据铅构造模式图解和△γ-△β图解,铅同位素主要来源于地幔,有部分地壳铅的加入;氢、氧同位素表明成矿流体具有变质热液和岩浆热液的双重性,成矿晚期热液有大气水成分加入;碳同位素表明成矿流体与砂质板岩关系密切,与地幔或深部流体有一定的关系,矿床成矿流体中的CO2很可能为壳幔混合;锶同位素研究表明,铲子坪金矿床的(87Sr/86Sr)i组成特征与华南陆壳重熔性花岗岩初始岩浆水的(87Sr/86Sr)i组成特征基本一致,表明其成矿作用可能与岩浆热液有关。铲子坪金矿成因类型为岩浆热液型。
Abstract:
Chanziping gold deposit is located in Xuefeng Mountain tectonic magmatic belt near the contact of the Baimashan composite granitic intrusions. Rock geochemical, sulfur, lead, carbon, hydrogen, oxygen and strontium isotopic composition of Chanziping gold deposit were analyzed to discuss the metallogenic material source and genesis.The results show that:the sulfide of the metal sulfide oreδ34S ranges from-7.58‰~+0.32‰,average-2.44‰, rich light sulfur, which indicates that the sulfur mainly comes from granitic magma sulfide, a portion of the formation sulfate mixed with sulfur. Lead isotopic composition is relatively stable and range narrowly. Accord-ing to lead model diagram and △γ- △β diagram, lead isotope mainly derived from the mantle, part of the earth’s crust lead to join. Hydrogen and oxygen isotope show the ore-forming fluid has the dual nature of the metamorphic hydrothermal and magmatic hydrothermal and mixed with some of the meteoric water in the late ore-forming hydrothermal. Carbon isotope indicate that ore-forming fluid is in close contact with sandy slate, and the relationship with the mantle or deep fluid. CO2 in the metallogenic fluid is likely to crust-mantle mixing. Strontium isotope research shows that composition features of the Chanziping gold deposit and south China conti-nental crust remelting granite initial magmatic water of (87Sr/86Sr)i composition has obvious characteristic similarity, suggests that the ore-forming processes may be related to magmatic hydrothermal. Genetic type of the Chanziping gold deposit is magmatic hydrothermal.
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