甘肃西秦岭新生代钾霞橄黄长岩中的球状分凝体及地幔流体反演

The Globule Segregations in the Cenozoic Kamafugite and An Inversion of Mantle Fluid,Western Qinling,Gansu Province

地幔流体在地质过程中的作用日益受到人们的重视,成为地球科学研究的一个前缘课题。提供了甘肃西秦岭新生代钾霞橄黄长岩中各种形态分凝体详细的岩相学、矿物学和矿物化学的资料,对分凝体的性质、深部地幔流体的成分及成因机制进行了讨论。研究表明,钾霞橄黄长岩中分凝体是软流圈地幔流体活动的记录,其成因机制与岩浆作用对软流圈的开放和软流圈上涌的条件下,原生钾霞橄黄长岩浆的分异作用(特别是液态不混熔作用),以及岩浆的抽提作用、动态熔融作用等综合作用有关。

The significances of the mantle fluid in geological processes have received more attention day by day, and became a frontier project in geosciences. This paper provides detailed petrographic, mineralogic and mineral-chemical data of the segregation with various forms in kamafugites from Western Qinling, Gansu Province, and probes into the nature of these segregations, the composition of the mantle fluid and generating mechanism of these segregations. The studies show that these segregations are records of the activities of asthenospheric mantle fluid. The generating mechanism of the segregation may be related to differentiation of the primary kamafugite magma（ especially liquid immiscibility）, combined with magma extraction and dynamic melting at the conditions of the magmatism opened to asthenosphere and the upwelling of the asthenosphere.