湖南东坡野鸡尾矿床H_2S-CH_4-CO_2流体包裹体研究

A LOW TEMPERATURE STUDY OF H_2S-BEARING INCLUSIONS FROM YEJIWEI TIN DEPOSIT, HUNAN

本文利用Chaixmeca冷热台详细研究了产于野鸡尾云英岩型锡矿床中的含H_2S包裹体低温相平衡,其结果S_(H_2S)熔化温度为-98±1℃,S_(co_2)的熔化温度为-80—-90℃,L_(H_2S)与L_(CH_4+co_2)混溶至L_(H_2O+CO_2)的温度为-68.6—-70.2℃,在-57.2—-55.6℃范围内包裹体均一至超临界流体。根据现有相图资料推测,这类包裹体的流体体系为H_2S-CH_4-CO_2体系,其组成满足:

H_2S-bearing fluid inclusions in quartz associated with chalcopyrite, pyrite, and stannite occur in the Yejiwei greisen-type tin deposit. The inclusions, single phase at room temperature, coexist with liquid-rich inclusions with Th 195—231℃ and salinity=0.6—2.3wt.%, and have an S_(H_2S) smelting temperature of-98℃, an S_(co_2), melting temperature of -90—-80℃, and two immiscible liquids (liquid H_2S and liquid CH_4) between -98℃ and -69℃, with a homogenization temperature of -55℃. From these data the composition of the inclusion fluid was estimated on the basis of the phase diagram of the H_2S-CO_2-CH_4 system.