湘南荷花坪地区王仙岭岩体地球化学特征及成矿作用

Geochemical Characteristics and Mineralization of Wangxianling Granite in Hehuaping area,Southern Hunan Province

王仙岭岩体由两期花岗岩组成,早期花岗岩发生钨锡矿化,晚期花岗岩无矿化显示。本文对两期花岗岩主量、稀土、微量元素特征、形成构造环境及其与成矿关系等方面进行对比研究,认为成矿花岗岩与不成矿花岗岩主要区别在于早期花岗岩富含电气石,B、F、Cs含量高,其岩浆分异演化程度高,电气石中Fe含量约占8.99%,F含量约占2.10%,而晚期花岗岩不含电气石或电气石含量很少,岩浆演化程度相对低。深层原因为王仙岭早期花岗岩形成软流圈地幔上涌峰期,壳-幔作用强烈,深源流体丰富,而王仙岭晚期花岗岩形成软流圈地幔上涌峰期之后,壳-幔作用较弱,成矿作用强度可能与壳-幔作用强度呈正相关性。

Wangxianling granite consists chiefly of two period granites.The early period granite takes place tungsten-tin mineralization which is related to Hehuaping tin-polymetallic deposit and the later period granite does not show mineralization.The comparative study on the petrochemistry,trace elements,genesis and mineralization feature about the two period granites in this paper argues that the difference between the early period granite and the later one is as below：the early period granite has the high content of B,F,Cs is rich in tourmaline which is rich in the content of Fe（about 8.99%） and F（about 2.10%） and processed strong magmatic differentiation;however,the later one does not have tourmaline or is poor in tourmaline so that its magmatic differentiation degree is lower.The deep-seated reason about the mineralization is that the early period granite was formed in the setting of the peak of upwelling of asthenosphere mantle that crust-mantle interaction was strong and the later period granite was formed after the peak so that crust-mantle interaction was relatively weaker.The strength of mineralization is correlated positively with the strength of crust-mantle interaction.