lntraplate orogenesis and its implications in metallogenesis
板内造山作用与成矿

The broadly intensive intraplate deformation and orogenesis in the China continent are usually considered as the distant effects of the force from plate convergent boundaries in traditional plate tectonics.However,there are not expected geodynamie relations between the intraplate orogenesis in the China continent and any convergent boundary.The intraplate orogenesis can not be simply explained as the distant effects of continental collision or plate subduction.This paper proposed an alternative interpretation attributing the intraplate deformation to the local lithospheric heterogeneity or discontinuity.Since formation of an integrated plate by plate suture, the geological evolution in a region is in the intraplate stage.The lithospheric heterogeneity and gravitational instability induced by plate collisions may trigger intensive intraplate deformation and even orogenesis.The time interval between the plate integration and the orogenic reactivation is decided by the levels of the lithospheric instability and the thermal disturbance from the Earth's depths. Distinguished from the orogenesis at the plate boundaries,the intraplate orogenesis lacks the processes of plate subduction and collision.The intraplate orogen has relatively simple history commonly initiated by lithospheric delamination and characterized by vertical accretion of the orogenic crust.The intraplate orogenesis will be completed by the other delamination event or the formation of a new lithosphere with light gravitational instability.Therefore,the intraplate orogenesis develops commonly along a ancient orogen. The feature of lower matured lithospheric structure in an ancient orogenic belt is not only one of the primary factors causing the lithospheric gravitational instability.A lower matured lithosphere contains huge volatiles and ore-forming elements and hence has higher potential ability to form ore deposits.Metallogenesis in an intraplate orogen is dependent to if sudden releasing ore-bearing fluids from various depths of the lithosphere-asthenosphere system.Consequently,the metallogenesis occurs mainly in the initial stage and the post-orogenic extension stage.