China's eastern parts of the causes of Cenozoic lithospheric mantle

Title: China's eastern parts of the causes of Cenozoic lithospheric mantle
　　Author: LIU Hai-quan
　　Degree-granting unit: Hefei University of
　　Keywords: peridotite xenoliths;; asthenosphere;; trace elements;; thinning;; North China Craton
　　Summary:
　　Hannuoba analysis, female mountain, Fangshan Panshishan and Cenozoic basalts in mantle peridotite xenoliths from major and trace element geochemistry, combined with published data in mantle peridotite xenoliths, the system compares the Chinese peridotite xenoliths from the eastern Paleozoic and Cenozoic peridotite xenoliths, ocean mantle, the rare earth magnets geochemistry of ancient cratons. China Cenozoic peridotite xenoliths major elements with similar oceanic mantle peridotite enriched mantle characteristics, and the ancient craton and the Paleozoic refractory mantle lithosphere has significant differences. Further primary - partial melting of trace elements in analog indication, ancient craton need to get a higher degree of partial melting (~ 15%), while China Cenozoic lithospheric mantle and oceanic mantle peridotite melting degree is relatively small, can lesser extent by the DMM through the separation of partial melting obtained (~ 5%), although the female mountain, and the individual samples have Panshishan ancient craton with a considerable degree of partial melting, but the isotopic evidence indicates female mountain and all the samples are loss Panshishan features, not the ancient lithospheric mantle residues. Paleozoic rocks in eastern China mantle spider diagram Ti negative anomalies compared to the extreme, Hannuoba female mountain, Panshishan, samples, and Fang Shan district mantle peridotite xenoliths from the ocean has a weak negative Ti anomalies, this anomaly and a weak negative DMM is similar, with the nature of the Paleozoic enriched mantle melt metasomatism by a variety of simulations, exclude the Cenozoic lithospheric mantle beneath eastern China from the ancient craton lithospheric mantle inherited possibilities. Experienced a lower degree of partial melting degree of separation after, REE distribution patterns with LREE loss characteristics, but similar to the OIB account of the nature of the melt Hannuoba, female mountain, Fangshan Panshishan and most samples have a "spoon-type" "inverted spoon-type" and the other light rare earth enriched REE pattern shape diagram, explain the nature of the media has a silicon-rich. Melt the sample account for Hannuoba more strongly, the petrographic evidence, the http://www.chinamagnets.biz/ main mode of the concentration of trace elements and relationships between tables Ming Hannuo Cenozoic lithospheric mantle beneath the dam through a silicon-rich Melt + Ol (olivine) → Opx ( orthopyroxene) + Silicon Melt poor response process that led directly to Nb and U enrichment. While the female mountain, Fangshan Panshishan lithosphere and mantle is mainly through the hidden account process. Combined with published data, indicate the equilibrium temperature minerals in eastern China has some of the lithospheric mantle heterogeneity, manifested in the central high and low north and south sides.
　　Degree Year: 2010