Heat Flow and Rheological Decompaction of the Crust and Upper Mantle in Rift and Plume Structures on the Eastern Margin of Asia

Abstract

Results of the correlation analysis of heat f low anomalies (Q) with distributions of density contrast ( -parameter) in rifting and plume structures on eastern margin of Asia are considered, which prove selective inverse correlation of these parameters in depth intervals corresponding to the position of the subcrustal viscous layer and asthenosphere. Rifting structures are characterized by ruptures in rigid layers displayed by maxima of the  -параметра, while plume-type central structures are characterized by concentrically zonal distribution of density contrast. The main contribution to the thermal anomalies in rifts is made by the subcrustal viscous layer. Thermal flow from the asthenosphere at the Ceinozoic boundaries of lithospheric plates is screened by subducting slabs. The identical correlation of Q and  -parameter in distant regions testifies to the same deep structure and universality of tectonic regimes on the eastern margin of Asia, where subduction, rifting and plume processes are coupled in space and time.