花岗岩混合成因研究及大陆动力学意义

Origin of hybrid granitoids and the implications for continental dynamics

岩相学特别是同位素地球化学研究显示 ,很多花岗岩并非起源于单一物源 ,而可能是壳、幔物质的二源 (元 )混合产物 ,也可能是三源 (元 )混合产物 ,如长英质上地壳物质、基性下地壳物质、幔源基性物质或陆壳、洋壳、地幔物质。因而 ,用花岗岩推断下地壳物质组成特性有时不一定可靠 ,但花岗岩混合成因研究却有可能提供有关地壳结构、生长演化以及地壳、洋壳、地幔三者相互作用关系的信息 。

The studies of petrology, particularly isotopic geochemistry suggest that many mantle granitoids are not derived from one source-component, but from a two source-component mixing such as crustal- and mantle materials three source-component mixing such as materials from felsic upper crust, mafic low crust and depleted mantle or from materials from ocean crust, continental crust and mantle, respectively. Thus, granitoids do not directly “image” their source-rock component, so can hardly image lower-crustal composition. However, the study of mixing origin of granites may provide important information on crustal growth, architecture and evolution as well as interaction of continental crust, ocean crust and mantle. This may be a new approach to continental dynamics.