熔体包裹体在镁铁质火山岩成因研究中的应用

Melt Inclusions and Their Applications on the Origin of Mafic Volcanic Rocks

熔体包裹体是矿物在生长或结晶过程中捕获的小的硅酸盐熔体,它保存了原生岩浆、岩浆演化以及源区性质等方面的重要信息。然而,全岩成分只保留了经历复杂地质过程（如分离结晶、岩浆混合、地壳混染和后期蚀变等）之后的＂混合＂成分,有关岩石起源方面的重要信息部分或全部消失。本文系统总结了熔体包裹体的研究方法,包括岩相学观察、挑选寄主矿物、加热均一化、镶嵌和磨制样品靶、成分分析等,介绍了熔体包裹体方法在镁铁质火山岩成因研究中一些应用实例。

Melt inclusions are small silicate melts trapped in minerals during growth or crystallization,which may preserve important information of the primary magma,process of magmatic evolution and nature of the source. In contrast,whole rock compositions only retain the ＂ mixed＂ compositions after complicated geological processes,including fractional crystallization,magma mixing,crustal assimilation and alteration,during which some or all of the important information about the origin of rocks may have disappeared. This paper presents the method of melt inclusion study,including petrological observation,selection of host minerals,rehomogenization of melt inclusions,mounting and polishing melt inclusions and compositional analyses of melt inclusions. Finally,this paper also introduces some examples on the application of melt inclusions in the study of the genesis of mafic volcanic rocks.