浙江八面山萤石矿床流体包裹体地球化学研究

STUDY ON FLUID INCLUSION GEOCHEMISTRY OF BA-MIANSHAN FLUORITE DEPOSITS OF ZHEJIANG PROVINCE

八面山萤石矿床流体包裹体可分为三大类型:Ⅰ气液包裹体,Ⅱ气体包裹体,Ⅲ含子矿物的多相包裹体;矿床成矿温度变化不大,主要集中在120～240°C之间。细粒条带状萤石矿石包裹体温度变化在115～250℃之间;巨晶块状萤石矿石和石英脉型萤石矿石包裹体温度集中在135～170℃之间。萤石矿床流体包裹体以低盐度成矿流体为主。成矿过程中起作用的成矿流体为KCl-H2O体系和CO2-CaF2-H2O体系,成矿溶液的离子类型属K+-Ca2+-HCO--F-型,KCl-H2O体系反映岩浆期后热液作用的结果,而CO2-CaF2-H2O体系可能反映了寒武纪矿源层成矿体系。通过包裹体研究,认为八面山萤石矿床是受地层-岩体-层间断裂共同控制"三位一体"的热液成因矿床。

There are three types of fluid inclusions in Bamianshan fluorite deposits,vapor-liquid inclusion,vapor inclusion and polyphase inclusions with daughter minerals.The ore-forming temperature varies slightly,mostly in 120～240°C.The inclusion temperature changes at a range of 115～250℃ in fine banded fluorite,while in megacryst massive fluorite and quartz vein fluorite at a range of 135～170℃.The fluid inclusion of fluorite deposits mainly are low salinity ore-forming fluid,and the ionic type of ore-forming fluid is K＋-Ca2＋-HCO--F-,there are two ore-forming fluid system in the hydrothermal process,the KCl-H2O system represents the results of later magmatic period and CO2-CaF2-H2O system may represents ore-forming system of the Cambrian source bed.According to the study on fluid inclusions,the Bamianshan fluorite deposit is a hydrothermal deposit controlled by strata,rock mass and interlayer fracture.