The timing and duration of the destruction of the North China Craton, which is pivotal to understanding the destruction mechanism and its geodynamic controlling factors, still remain controversial. On the basis of the principles of magma genesis and evolution, first we outline magmatic expressions that can be related to cratonic destruction, then use magmatic and basin evolution trends to constrain the timescale of the lithospheric thinning in North China. The main conclusions include: (1) the thinning of the lithosphere beneath the North China Craton might have started, at least locally, since late Carboniferous-late Triassic, attained its climax during the late Jurassic-early Cretaceous, and continued till the end of late Cretaceous-early Cenozoic. The destruction of the North China Craton was a relatively slow, rather than a dramatic process. (2) The weakened lithospheric zones along the margins and interiors of the craton played an important role in cratonic destruction, partly accounting for the heterogeneous pattern of cratonic destruction. (3) The tectonic factors that controlled the destruction of the North China Craton may be multiple. The late Carboniferous southward subduction of the Paleo-Asian plate and the late Triassic collision between North China and South China may have re-activated the craton by influencing the thermal and integral structure of the craton. The Pacific subduction underneath the eastern Asian continent played a determinant role in the cratonic destruction, governing the distribution patterns of post-Mesozoic basins and major tectonic configuration, temporal change of magmatism and formation of the North-South gravity lineament.
A National Science Foundation of China(NSFC) major research project,Destruction of the North China Craton(NCC),has been carried out in the past few years by Chinese scientists through an in-depth and systematic observations,experiments and theoretical analyses,with an emphasis on the spatio-temporal distribution of the NCC destruction,the structure of deep earth and shallow geological records of the craton evolution,the mechanism and dynamics of the craton destruction.From this work the following conclusions can be drawn:(1) Significant spatial heterogeneity exists in the NCC lithospheric thickness and crustal structure,which constrains the scope of the NCC destruction.(2) The nature of the Paleozoic,Mesozoic and Cenozoic sub-continental lithospheric mantle(CLM) underneath the NCC is characterized in detail.In terms of water content,the late Mesozoic CLM was rich in water,but Cenozoic CLM was highly water deficient.(3) The correlation between magmatism and surface geological response confirms that the geological and tectonic evolution is governed by cratonic destruction processes.(4) Pacific subduction is the main dynamic factor that triggered the destruction of the NCC,which highlights the role of cratonic destruction in plate tectonics.
