河北峪耳崖金矿花岗岩矿物学地球化学特征与岩浆演化

MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS AND MAGMATIC EVOLUTION OF GRANITE IN YUERYA,

通过花岗岩的矿物学和ＲＥＥ特征研究，探讨花岗岩岩浆的演化。正长花岗岩和碱长花岗岩中的斜长石分别为更长石和钠长石，两种花岗岩中的碱性长石均为正长石，从正长花岗岩到碱长花岗岩Ｏｒ含量增加，正长花岗岩和碱长花岗岩的黑云母分别为镁黑云母和铁黑云母，矿物学特征和ＲＥＥ特征均表明从正长花岗岩岩浆向碱长花岗岩岩浆演化的趋势。应用分离结晶岩石学混合计算表明，从正长花岗岩岩浆大约分离结晶出６％～２４％的斜长石和５％～７％的黑云母，形成６９％～８８％的碱长花岗岩岩浆。从正长花岗岩岩浆向碱长花岗岩岩浆演化，岩浆的密度减小，粘度增加，聚合程度增加。

This paper discusses the evolution of granite magma by mineralogical and geochemical characteristics Plagioclases in syenogranite and alkali feldspar granite are oligoclase and albite, respectively Alkali feldspars in granites are orthoclases and increase from syenogranite to alkali feldspar granite Biotites in syenogranite and alkali feldspar granite are Mg-biotite and Fe-biotite, respectively Granite magma evolved to alkali-rich and Fe-rich from syenogranite to alkali feldspar granite REE characteristics suggest an evolution tendency from syenogranite to alkali feldspar granite Petrological mixing calculation suggests that the evolution of an alkali feldspar granite from a syenogranite is controlled by fractionalcrystallization