个旧锡矿花岗岩的氧氢碳稳定同位素研究

个旧锡矿是世界闻名的特大型锡多金属矿床,大量工程揭示,锡矿与花岗岩在时空分布上有着密切的联系,本文试图通过对矿区岩石、矿物及其流体包裹体的氧氢碳稳定同位素的测试研究,进一步揭示锡矿化与花岗岩之间的内在联系和探索成岩成矿物质来源。

The Study of Isotopic Composition of Oxygen , Hydrogen and Carbon in Granites of Tin Deposits, Gejin

Isotopic composition of oxygen in Gejiu granites is characterized by abun dance of 18O, which indicated that the source material was derived from the shallow sedimentary crust.In consideration of the fact that the isotopic composi- tions of oxygen and hydrogen in magma liquid are similar with that of the "magmatic water" defined by Taylor the tin-bearing granites should be classi- fied genesically as an anatexis magmatic-granite in the shallow source (it cor- respond to S-type defined by Chappell). The isotopic composition of oxygen, hydrogen and carbon in Gejiu tin de- posite shows that the tin mineralization occurred mainly in the deuteric thermal fluid stage.The ore-bearing fluids were mainly derived from the magmatic wa- ter, and a large of atmospheric water joined to it only in its later stage. Some carbons in the ore-bearing fluid was come from the organic carbon resulted from marblization of the surrounding rocks.