大冶-城门山夕卡岩矿床石榴子石和辉石中熔融包裹体成分研究  

Compositions of melt inclusions in garnet and pyroxene from skarn deposits distributed in the area from Daye to Chengmenshan

作　　者：赵劲松[1] 赵斌[1] 张重泽[1] 王冉[1] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2003年第6期540-550,共11页Geochimica

基　　金：国家自然科学基金(49772115)

摘　　要：在长江中下游地区,Fe、Cu(Au)和Au(Cu)夕卡岩矿床广泛分布,用电子探针测量了大冶-城门山一带7个矿床夕卡岩矿物中熔融包裹体里的固相(晶质和非晶质)成分。根据这些分析结果及已发表的熔融包裹体均一温度测量数据,对该地区熔融包裹体的成分特点及其意义以及岩浆夕卡岩形成的物理化学条件进行了研究和探讨。夕卡岩矿物中熔融包裹体主要含两种成分:成分接近辉石的钙、铁、镁硅酸盐相和成分接近石榴子石的钙、铁、铝硅酸盐以及含SiO2等氧化物的碳酸盐相。夕卡岩矿物中硅酸盐熔融包裹体在均一温度和成分方面与含子矿物的流体包裹体和“盐熔”包裹体显著不同。岩浆成因夕卡岩形成温度主要介于900～1150℃之间,其主要成分与其他成因夕卡岩没有明显区别。Fe, Cu (Au) and Au (Cu) skarn deposits are far and wide scattered over a large area of the middle lower reaches of the Yangtze River. Determinations of the compositions for solid phases (crystalline substance and amorphous substance) in the melt inclusions within skarn minerals from seven ore deposits distributed from Daye to Chengmenshan are carried out by electron microprobe. According to these results and published homogenization temperatures of the melt inclusions, we have studied and approached compositional characteristics of the melt inclusions and their significance as well as physico chemical conditions of skarn formation of magma genesis. The melt inclusions in skarn minerals have mainly two compositions: Ca, Fe, Mg bearing silicate phases that are close to pyroxene in composition and Ca, Fe, Al bearing silicate phases that are similar to garnet composition as well as SiO2 bearing and other oxides bearing carbonate phase. Silicate melt inclusions are obviously different from daughter minerals bearing fluid inclusions and “salt melt”inclusions in respect of homogenization temperatures and the compositions. Skarn formation temperatures of magmatic genesis are between 900 ℃and 1 150 ℃. There is no distinct difference between the composition of magmatic skarns and the skarns of other genetic types.

关 键 词：长江中下游地区 夕卡岩矿床 电子探针 熔融包裹体 包裹体成分 

分 类 号：P575.1[天文地球—矿物学] P599[天文地球—地质学]