吉林省大灰沟硅灰石岩的地质特征及成因讨论

Geological characteristics and Genesis of Dahuigou Wollastonitite, Jilin Province

吉林省大灰沟硅灰石岩赋存于泥质条带大理岩夹硅质条带大理岩层内，其直接围岩为大理岩。硅灰石岩呈似层状、透镜状及不规则状，组成矿物有硅灰石（９５％以上），少量透辉石、石榴石和方解石等。通过对硅灰石岩形成的地质条件、岩石学、矿物学、地球化学的研究和前人实验研究表明，本区硅灰石岩为区域变质热液作用形成的交代岩，其中的硅灰石属三斜硅灰石。华北地台北侧（槽区）的辽宁、吉林省境内发育多处硅灰石岩矿床和矿点，均呈透镜状、似层状产于各种硅质大理岩层内。大灰沟硅灰石岩就是其中之一。

Dahuigou wollastonitite of Jilin province occurs in strata of argillaceous banded marble intercalated with siliceous banded marble with the direct host being marble,Stratoid in form,it consists mainly of wollastonite(over 95%),together with small amounts of diopside,garnet and calcite。Geological,petro-logical, mineralogical and geochemical studies of wollastonitite combined with experimenta.researches conducted by previous workers indicate that wollasto-nitite of this area is a kind of metasomatite formed by regional metamorphic hydromermal process,and the wollastoite within it belongs in low-temperature triclinowollastonite(a-CaSiO_3)