辽宁张家沟硫铁矿床流体包裹体与稳定同位素地球化学研究

PYRITE DEPOSITS IN ZHANGJIAGOU,LIAONING: STUDIES OF FLUID INCLUSINOS AND STABLE ISOTOPES

张家沟矿区存在两种不同类型的矿体，其地质特征不尽相同。通过对矿床流体包裹体和稳定同位素地球化学特征的研究表明，矿床的形成温度为１４０～３００℃，成矿硫逸度ｌｇｆＳ２变化在－１０．３９～－１５．７０，ｌｇｆＯ２变化在－３４．１４～－４５．１６，ｐＨ值变化在４．６４～６．１５。早期成矿流体为一种低盐度高密度的热流体，随矿化作用的进行，成矿流体向弱酸性弱还原性方向演化。成矿作用以深部硫源的海底火山喷气热水沉积为主，后期以变质改造热液叠加为特征。层状矿体和脉状矿体为两次热事件形成不同矿化的产物。

There lie two different pyrite deposits in Zhangjiaguo district with vario us geological charaters. Geochemical studies regarding fluid inclusions and stable isotopes suggest that the deposits are distinguished by mineralizing temperature between 140 and 300℃, lg f S 2 between -10.39 and -15.70, lg f O 2 between -34.14 and -45.16, and pH between 4.64 and 6.15.Mineralizing solutions evolved from a low salinity, high density, hot fluid at the early stage to a slight acidity, reduced one at the late stage, consisting mainly of sulfur bearing hot waters by seafloor volcanic exhalation along with those by late metamorphism. Stratiform and vein orebodies represent respectively two different hot events.