古地幔流体及其在大陆克拉通地幔演化中的意义——以华北地台为例

PALEOMANTLE FLUID AND ITS MEANING IN THE EVOLUTION OF CONTINENTAL CRATON MANTLE

古生代含捕虏体的金伯利岩和新生代含捕虏体的玄武岩同出于华北地台，提供了研究自古生代以来岩石圈演化的深源探针。古生代含金伯利岩的侵位表明古生代时曾存在冷厚的岩石圈；而新生代含捕虏体玄武岩的喷发，表明新生代时存在热薄的岩石圈。岩石圈减薄与“大洋化”是层圈物质交换作用在一定历史阶段中的反映。地幔流体是地幔演化产物，反之又作用于地幔演化。富含地幔流体的幔内剪切带及交代矿物层作为幔内软薄弱带，存在热、流体、化学及机械的耦合，是岩石圈减薄拆沉作用的重要界面位置。

Palaeozoic kimberlites borne xenolithes and basalts borne xenolithes which occured in North China platform, offer the deep source probe on researching the evolution of continental lithosphere began with Palaeozoic. The data of diamondifeous kimberlites and their xenolithes, show there was a cold, thick lithosphere presented in Palaeozoic. The basalt borne xenolithes indicate there was a hot, thin lithosphere in Cenozoic. The lithospheric thining and “oceanization” are the results of crut mantle interaction at special history stage. The present formations of paleo mantle fluids in North China platform are reported in this paper in detail. It is regarded that the mantle fluids are the results of mantle evolution, and they also react on the mantle evolution. The shear zones and metasome layers in mantle with aboundant fluids acted as the weak zones, represented the unite of heat, fluid, chemistry and mechanism, are the major fields of lithosphere thining and delamination.