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Mesozoic decratonization of the North China block

Simon A.Wilde  Elena Belousova  William L.Griffin  
【摘要】:正Cratons are old,stable parts of the continental crust that have survived at least since Proterozoic time and have not undergone strong magmatism or tectonism since their stabilization. Traditionally,the growth of continental crust in the North China craton is considered to have been complete by Paleoproterozoic time,Phanerozoic events being largely restricted to surrounding orogenic belts.However,the eastern part of the North China craton contains large volumes of Mesozoic igneous rocks,with widespread metamorphic core complexes and pull-apart basins.Hf isotope compositions of magmatic zircon grains from igneous rocks in the Liaodong Peninsula indicate that widespread late Mesozoic granitoids formed by partial melting of ancient crust,but with significant input of a mantle component via magma mixing and crustal assimilation.This magmatism has resulted from removal and modification of lithospheric mantle,accompanied by asthenospheric upwelling.The Hf isotopic signatures thus record the addition of juvenile crust beneath the eastern part of the North China craton,which appears related to major extension and possibly slab rollback of the Pacific plate.Whatever the mechanism,it is apparent that since ca.200 Ma,ancient lithosphere beneath the eastern North China craton has been progressively reactivated and replaced, resulting in"decratonization."Tertiary to Holocene volcanism in the area and major subsidence around the Gulf of Bohai suggest that the effects of the process are continuing.Similar processes probably operated in the geological past,leading to significant modification of continental crust and requiring reconsideration of mechanisms for continental breakup and dispersal and of continental growth rates.

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1 Simon A.Wilde;Elena Belousova;William L.Griffin;;Mesozoic decratonization of the North China block[A];中国科学院地质与地球物理研究所2008学术论文汇编[C];2009年
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3 陈斌;翟明国;邵济安;;Petrogenesis and significance of the Mesozoic North Taihang complex:Major and trace element evidence[A];中国科学院地质与地球物理研究所二○○三学术论文汇编·第一卷(地球动力学)[C];2003年
4 周新华;杨进辉;张连昌;;Metallogenesis of superlarge gold deposits in Jiaodong region and deep processes of subcontinental lithosphere beneath North China Craton in Mesozoic[A];中国科学院地质与地球物理研究所二○○三学术论文汇编·第一卷(地球动力学)[C];2003年
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6 ;Mesozoic lithosphere destruction beneath the North China Craton:evidence from major-,trace-element and Sr-Nd-Pb isotope studies of Fangcheng basalts[A];中国科学院地质与地球物理研究所2002学术论文摘要汇编[C];2002年
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10 Simon A.Wilde;;A review of the geodynamic setting of large-scale Late Mesozoic gold mineralization in the North China Craton:an association with lithospheric thinning[A];中国科学院地质与地球物理研究所二○○三学术论文汇编·第一卷(地球动力学)[C];2003年
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