The crustal thickness of the Northeastern Tibetan Plateau and its geodynamic implications for deformation

There is ongoing debate regarding the mechanism of crustal thickening of the Tibetan Plateau's northeastern margin. To address this, we integrated crustal thickness data from deep seismic sounding with H-κ stacking receiver function analyses using data from permanent and portable seismic stations. The resulting regional crustal thickness model indicates a gradual decrease in crustal thickness from the southwest to the northeast across the Northeastern Tibetan Plateau, suggesting a mode of vertically uniform shortening deformation. However, varying crustal strength among different tectonic units leads to diverse deformation and thickening mechanisms. While the overall crust exhibits extrusion thickening, localized areas such as the Gonghe Basin and Tianshui Basin show crustal thinning. Soft blocks prone to plastic deformation exhibit significant thickening, whereas rigid blocks with higher strength only thicken to a certain extent near their boundaries. In some areas beneath the block boundary zones, the crust exhibits little to no thickening and may even undergo thinning. This highlights how the strength of the blocks influences the processes of crustal shortening and vertical thickening.