岩浆岩中的熔体包裹体

熔体包裹体是岩浆岩矿物生长过程中捕获的天然岩浆珠滴 ,它们有效地保存了大量有关其主矿物形成时周围岩浆介质的物理化学信息 ,所以它们是其主矿物结晶演化史的忠实记录员 ,它们能够提供岩浆系统成分和演化的重要信息。文中对熔体包裹体研究的若干基本原理进行了讨论 ,它们涉及 :(1)熔体包裹体的一般特征 ;(2 )熔体包裹体封闭过程中和封闭后的演化 ;(3)熔体包裹体的均一化研究 ;(4 )熔体包裹体化学成分和挥发组分研究。熔体包裹体研究可以对岩浆岩石学中的一些重要问题进行更为深入的探索 :(1)重建天然岩浆结晶演化的热历史 ;(2 )提供有关岩浆沿下降液相线的成分数据 ;(3)查明天然岩浆结晶演化过程中化学成分的变迁规律 ;(4 )解决岩浆岩石学中的一些疑难问题 ,如岩浆不混溶作用、岩浆混合作用、岩浆混染作用、岩浆中硫的性状、地幔部分熔融和地幔交代作用等方面的问题。将熔体包裹体数据和常规的岩石学、地球化学和实验岩石学信息综合一体 ,可以提高我们模拟岩浆作用过程的能力。熔体包裹体研究已经成为现代岩浆岩石学的一个独立的分支 ,其前景十分广阔。

MELT INCLUSIONS IN MAGMATIC ROCKS

Melt inclusions are small droplets of natural magma trapped in different magmatic minerals during their growth and effectively conserve a lot of physico\|chemical informations of surrounding magmatic media at the time of formation of their host mineral. For this reason, they are the faithful recorders of the crystallization and evolution history of their host minerals and they can provide important information on the composition and evolution of magmatic systems. Some basic principles of melt inclusion studies are discussed: (1)general characteristics of melt inclusions; (2)evolution of melt inclusions during and after trapping; (3)homogenization on melt inclusions; and (4) chemical compositions and volatile contents of melt inclusions. Melt inclusion studies allow us to concentrate on some important topics in magmatic petrology: (1) to reconstruct the thermal history of crystallization evolution of natural magma; (2)to provide the data on the composition along the descent liquidus of magma; (3)to examine the chemical variation in the course of crystallization evolution of natural magma; and (4)to explore and resolve various doubts and difficulties of magmatic petrology, such as: magma immiscibility, magma mixing, magma contamination, behaviour of sulphur species in magma, mantle partial melting, and mantle metasomatism. Combining melt inclusion data with conventional petrological and geochemical information and experimental petrology can increase our ability to model magmatic processes.The melt inclusion study has become an indispensable branch of the modern magmatic petrology and holds great promise for the future.