华北克拉通岩石圈地幔的锂同位素特征与熔体改造作用

Lithium isotopic characteristics of the lithospheric mantle beneath North China Craton and the melt modification

华北克拉通是显生宙以来全球古老克拉通破坏最为剧烈的地区。华北克拉通破坏及其相关的科学问题引起了国内外地质学家的广泛关注。有关华北克拉通破坏的研究已取得了许多重要进展,使我们认识到其破坏不仅表现为岩石圈厚度的剧烈减薄,更重要的是岩石圈地幔的物质组成与性质发生了巨大转变,即从古生代克拉通型转变为新生代大洋型。本文在综述华北地幔捕虏体锂同位素地球化学特征的基础上,进一步揭示了华北岩石圈地幔高度不均一的组成特征,以及不同来源的熔体对岩石圈地幔的改造作用,为深入认识华北岩石圈地幔的转变过程提供进一步的制约。

The North China Craton is the most strongly destructed region of ancient cratons in the world since the Phanerozoic era. The destruction of North China Craton and its related scientific issues have attracted extensive attention of geoscientists at home and abroad. Much important progresses have been made in the study of the destruction of North China Craton. It is recognized that the destruction of North China Craton is not only reflected by the severe thinning of the lithosphere beneath North China Craton, more importantly, but also reflected by the huge transformation of component and property of the lithospheric mantle, from the Paleozoic cratonic type to Cenozoic oceanic type. On the basis of summarizing the geochemical characteristics of lithium isotopes of mantle xenoliths in the North China Craton, this paper has further revealed the highly inhomogeneous feature for compositions of the lithospheric mantle beneath the craton and the modification of lithospheric mantle by variously sourced melts, and has provided further constraint for understanding the transformation process of the lithospheric mantle beneath the craton.