接触交代夕卡岩型矿床中石榴子石和辉石成分特点及其与矿化的关系

本文对中国十四个接触交代钙夕卡岩矿床和钙-镁夕卡岩矿床中的三百多个样品的石榴子石和辉石成分进行了电子探针分析。不同矿床类型的石榴子石和辉石成分代表着钙夕卡岩矿床的十个矿种(Fe、Fe-Cu、Pb-Zn、W、Sn、Sn-Mo-Bi-W、、W-Bi-Cu-Mo、Cu-Zn、Cu-Sn、W-Zn-Cu)和钙-镁夕卡岩矿床的三个矿种(Fe-Cu、Mo、Pb-Zn)。石榴子石和辉石成分变化范围大,大多数石榴子石是含锰铝榴石+铁铝榴石+镁铝榴石小于15％(摩尔百分数)的钙铝榴石-钙铁榴石固溶体;大多数辉石是含小于5％的锰钙辉石的透辉石-钙铁辉石固溶体。有些Pb-Zn钙-镁夕卡岩矿床中的辉石显示出Mn含量有所增加。只有Sn和W钙夕卡岩矿床及Pb-Zn钙-镁夕卡岩矿床含(Sps+Alm+Pyr)总量大于15％的石榴子石。石榴子石和辉石成分与夕卡岩矿床金属矿化类型之间有某些联系。

COMPOSITIONAL CHARACTERISTICS OF GARNETS AND PYROXENES IN CONTACT-METASOMATIC SKARN DEPOSITS AND THEIR RELATIONSHIP TO METALLIZATION

The compositions of more than 300 garnets and pyroxenes from fourteencontact-metasomatic calcic skarn deposits and calcic-magnesia skarn deposits inChina have been studied by electron microprobe technique. The compositionsof garnets and pyroxenes from a large variety of ore types represent ten majorclasses of calcic skarn deposit (Fe, Fe-Cu, Pb-Zn, W, Sn, Sn-Mo-Bi-W, W-Bi-Cu-Mo, Cu-Zn, Cu-Sn, and W-Zn-Cu) and three major classes of calcic-magnesia skarn deposit (Fe-Cu, Mo, Pb-Zn). Garnets and pyroxenes show a wide range in composition, but the majorityof garnets are grossular andradite solid solutions containing lesst han 15 mole%spessartine+almandine+pyrope, whereas the majority of pyroxenes are diopsi-de-hedenbergite solid solutions containing less than 5 mole% johannesenite.Some pyroxenes from Pb-Zn calcic-magnesia skarn deposits display an increasein Mn content. Only Sn-W calcic skarn deposits and Pb-Zn calcic magnesiaskarn deposits contain garnets with more than 15 mole% spessartine+almandine+pyrope. Some relationships have been observed between the composition ofgarnets and pyroxenes and the mineralization type of economic metals in theskarn deposits.