【摘要】 与原始岩浆组成 (δ1 8O=8.36× 1 0 - 3)相比 ,铜厂花岗闪长斑岩的氧同位素在纵向上存在着 3个特征区段 :1中段 (标高 0～ 80 m之间 )样品接近原始岩浆1 8O值 ;2上段 :在此之上的样品 δ1 8O值变化区间很大 ( 5.4 3～ 1 0 .86)× 1 0 - 3 ,有富集 1 8O的 ,也有亏损 1 8O的 ;3下段 :标高在 0 m以下深部未 /弱蚀变斑岩样品的δ1 8O值均一 ,亏损1 8O,集中在 ( 6.8± 0 .5)× 1 0 - 3范围内。研究表明 ,这种现象是岩浆流体、深部非岩浆流体和浅部大气降水等 3种不同来源的热液流体在不同温度、水 /岩比环境下发生水岩交换综合形成的更多还原

【Abstract】 Three general categories of the oxygen isotopic syetematics are observed in the Tongchang porphyry body: (1) altered granodiorite porphyries at 0～+80 m level which exhibit close to normal 18 O characteristics, (2) rocks below 0mwhich generally exhibit 18 Odepletion (δ 18 O=(6.8±0.5)×10 -3 ), and (3) rocks above +80m which exhibit in some case 18 Oenrichment and in other case 18 Odepletion (δ 18 O=(5.43～13.1)×10 -3 ), relative to primary magmatic δ 18 O=8.36×10 -3 . The complexity of δ 18 O values of rocks at higher and lower levels is a result of different alteration environments which depend on temperature, water/rock ratios and the history of three exchanging hydrothermal fluids including magmatic fluid, deep scatted nonmagmatic fluid and meteoric water.更多还原