浙江省铜矿床的稳定同位素地球化学特征

STABLE ISOTOPIC GEOCHEMICAL FEATURES OF COPPER DEPOSITS IN ZHEJIANG PROVINCE

浙江省铜矿床硫化物的矿δ34S值一般变化在-6‰～＋10．5‰之间，以正值为主，大多富集重硫，接近陨石硫；矿石铅同位素组成，在铅构造模式图上只有细碧角斑岩型和混合岩化型矿床的值域位在上地幔和下地壳曲线之间，其它类型（包括矽卡岩型、斑岩型和热液型等）矿床位于造山带曲线之上。这反映了不同类型铜矿床的成矿物质来源存在着差异。浙江省铜矿床的氢、氧同位素组成，矿物的δ18O多为正值，变化范围为＋4‰～＋12‰之间，在δ18O水—δD相关图上，细碧角斑岩型矿床具低δ18O水值高δD值域，混合岩化型矿床为高δ18O水值低δD值域的特征，这表明它们的成矿流体分别混合有海水和变质水的特征，其它类型矿床的成矿流体则多为岩浆水与大气降水的混合型。

The δ34S values of copper deposits in Zhejiang province range gcnerally from - 6‰ to＋10.5‰, of which the posltive vaIue is predominant and rich-heavy sulphur, being close tothe aerolite sulphur; In plumbotectonic model diagram, the lead isotopic compositions of ore min-eral for spilite - keratophyre type and migmatization type lie between upper mantle and lowercrust, however, other type deposits (including skarn type, porphyry and hydrothermal type de-posit ect. ) are at upper part of orogenic belt curve. This shows that mineralizing material sourcesin various types of the copper deposits are different.The δ18O values of mineral from these copper deposits are from＋4‰ to ＋12‰. In δ18OH2Oversus δD diagram, the spilite-keratophyre type deposits have lower δ18OH2O and higher δD val-ue, and the migmatization type deposits have higher δ18OH2o and lower δD value. The conclusionindicates that the mineralizing fluids of spilite-keratophyre type and migmatization type belongto a mixed fluid of seawater and metamorphic water, and the ore-forming fluids of other typedeposits (including skarm type, porphyry and hydrothermal type deposit etc. ) are mostly themixed product of magmatic solution and meteoric water.