摘要
华南某些含锡斑岩体的化学成分以富硅、贫钙、镁、铁、富碱为特征。其分异指数(DI)一般在90％以上,固结指数低于3,属张裂性花岗岩。根据闻广提出的含锡岩体b值在1～8之间,s值在79～84之间的看法,含锡斑岩的b值和s值均位于锡矿化区间。含锡斑岩体的微量元素以高氟、富铷、贫锶、贫钡为特征。铌钽比值近于1。稀土元素分析表明:∑REE含量较高,相对富集重稀土,铕出现显著负异常。初始锶同位素比值(^(86)Sr/^(87)Sr)_i等于0.711～0.716。说明含锡斑岩体的岩浆系由下部地壳物质重熔而成。
The characteristics of the chemical composition of the tin-bearing porphyriesare rich in silicon and alkali contents, but poor in calcium, magnesium and ironwith the differentiation index (DI)>90 and the solidification index (SI)<3,belonging to tension granite. Based on Wen Guang the b values and the s valuesof tin-bearing bodies respectively vary between 1 and 8 and between 79 and 84,so both values of b and s of the tin-bearing porphyries are in the tin-mineralizationspace. The characteristics of their trace elements are rich in Rb and Fcontents and poor in Sr and Ba. The ratio of Nb/Ta is about 1. As shown bythe REE analysis, REE contents is higher. Compared with the granite of SouthChina, the tin-bearing porphyries have higher HREE contents and an obviousnegative Eu anomaly. The initial ratio of ^(87)Sr/^(86)Sr is 0.711 to 0.716, whichindicates that the tin-bearing porphyries are the product of remelting the lowcrust.
基金
国家科学基金
关键词
斑岩
含锡
岩石化学
地球化学
特征
porphyry
petrography
geochemistry/the south of China
