晋北火山岩型金银矿床同位素地球化学特征  

ISOTOPE GEOCHEMSTRY OF VOLCANIC Au-AgDEPOSITS IN NORTH SHANXI PROVINCE

作　　者：李兆龙[1] 张连营[1] 骆华宝 

机构地区：[1]冶金部天津地质研究院

出　　处：《地球学报》1994年第Z1期145-151,共7页Acta Geoscientica Sinica

摘　　要：晋北地区是浅成低温热液金银矿床重要分布区。金银矿床与火山岩岩体密切相关。与成矿有关的石英斑岩、花岗斑岩基Ｒｂ－Ｓｒ等时线年龄为１３６－１６７Ｍａ，为燕山早中期产物，（￣８７Ｓｒ／￣８６Ｓｒ）。为０．７０５８－０．７０６５，属幔壳混源型。铅同位素资料表明，支家地银矿和刁泉银、金、铜矿铅同位素组成与高于在组白云岩及有关次火山岩岩石铅组成相似，可能均属壳幔混合源。耿庄金矿铅同位素属异常铅。金银矿床的δ￣（３４）Ｓ值分布范围为－０．８‰－＋９．６‰，算术平均值为３．８５‰，为岩浆热液型特征。成矿流体氢氧同位素及碳酸盐的碳氧同位素组成特征表明，其方解石、菱铁矿等为内生热液成因，成矿流体δ￣（１８）Ｏ＿（Ｈ＿２ｏ）值向降低方向演化，向大气降水线漂移，即成矿流体中大气降水的加入更加明显。In the North Shanxi occur many epithermal Au-Ag deposits which are closely related to volcanicand sub-volcanic rocks, especially to quartz porphyrite and granitic porphyrite. Their Rb-Sr ischronease of 130-167 Ma indicate that the rocks are products of middle Yanshanian period and their initial￣（87）Sr/￣（86）Sr of 0. 7058-0. 7065 suggests that they are the products of mixing of crust and mantle.The Pb isotope composition of the silver ore in the Zhijiadi Mine and the Ag-Au-Cu ore on theDiaoquan Mine is comparable to those of dolomite uf Gaoyuzhang Fornmtion and the relavent subyol-canics, probably ferived from mixed sources of crust and mantle. The pb isotope data of Au-ore fromthe Genszhuang Mine is considered to be abnornial. The δ￣（34）S values of these deposits range from0. 8‰to 9. 6‰（arithmatic average of 3. 85‰） ,showing characteristics of volcanic hydthermalmineralization. The δ￣（18）O_H₂O of ore fluid value decreases with evolution as result of more meteoric wa-ter incorporation into metallogeny.

关 键 词：火山岩型金银矿床 同位素地球化学 晋北 

分 类 号：P5[天文地球—地质学]