High oxygen fugacity magma:implication for the destruction of the North China Craton

作者：Zhekun Zhang,Mingxing Ling,Lipeng Zhang,Saijun Sun,Weidong Sun

摘要：The mechanism of lithospheric removal and destruction of the North China Craton(NCC)has been hotly debated for decades.It is now generally accepted that the subduction of the(Paleo)-Pacific plate played an important role in this process.However,how the plate subduction contributed to the craton destruction remains unclear.Here we report high oxygen fugacity(fO2)characteristics of the Yunmengshan granite,e.g.,hematitemagnetite intergrowth supported by zircon Ce^4+/Ce^3+ratios and apatite Mn oxygen fugacity indicator.High fO2 magmas are widely discovered in Late Mesozoic(160-130 Ma)adakitic rocks in central NCC.The origin of high fO2 magma is likely related to the input of the"oxidized mantle components",which shows a dose connection between plate subduction and destruction of the craton.The research area is~1500 km away from the current Pacific subduction zone.Considering the back-arc extension of Japan Sea since the Cretaceous,this distance may be shortened to~800 km,which is still too far for normal plate subduction.Ridge subduction is the best candidate that was responsible for the large scale magmatism and the destruction of the NCC.Massive slab-derived fluids and/or melts were liberated into an overlying mantle wedge and modified the lithospheric mantle.Rollback of the subducting plate induced the large-scale upwelling of asthenospheric mantle and triggered the formation of extensive high fO2 intraplate magmas.

发文机构：CAS Key Laboratory of Mineralogy and Metallogeny Laboratory for Marine Mineral Resources State Key Laboratory of Isotope Geochemistry.Guangzhou Institute of Geochemistry Center of Deep Sea Research University of Chinese Academy of Sciences

关键词：HIGHoxygenFUGACITYDecratonizationNorthChinaCRATONPlateSUBDUCTION

分类号： P58[天文地球—岩石学][天文地球—地质学]