造山岩套中镁铁质和长英质岩浆的相互作用研究进展

ADVANCES IN STUDY ON THE INTERACTION BETWEEN MAFIC AND FELSIC MAGMAS IN OROGENIC SUITES

结合2002年9月14～21日在意大利中部召开的"欧洲花岗岩网络"年会的会议讨论和野外考察内容,评述了镁铁质和长英质岩浆的相互作用关系以及镁铁质熔体在巨量花岗岩浆形成中的作用。在花岗岩岩基内,不仅出露有狭义的花岗岩,还可见到更富镁铁质的岩石,例如辉长岩和闪长岩。一般,这些镁铁质岩石,既可能是幔源母岩浆结晶的产物,或是岩浆混合和分异-同化作用中的端员组分,也可能代表了下地壳源区的物质,或者是导致大陆壳部分熔融的热源物质记录。对镁铁质和长英质岩浆相互作用关系的研究,有助于限定造山作用过程中地壳物质再循环和新的地幔物质加入的相对贡献。

Progress made thanks to the great number of the geochemical and magmadynamical studies over the last twenty years has allowed important insights into interaction between mafic and felsic melts, subject of Eurogranites 2002 held on September 1421,2002 in central Italy. The present review addresses the interaction relationship between mafic and felsic magmas, and the role of mafic melts in generation of voluminous granitic magmas, combining with the discussion of prefield meeting workshop, and field excursion of Eurogranites 2002. In granitoid batholiths,there are not only granites sensu stricto, but also many mafic rocks (e.g., gabbro and diorite). In general, the mafic rocks may be mantlederived parental magmas, end members in magma mixing and fractionationassimilation processes, material from lower crustal source regions, and/or heat sources that drive partial melting of the overlying continental crust. Such study of the relationship between mafic and felsic magmas can provide valuable constraints on the relative role of crustal recycling and new mantle additions to the continental crust during orogenic processes.