Abstract To provide constraints on the formation mechanisms of intracontinental volcanisms and intriguing lithospheric thickness variations in the East Sayan Mountains and surrounding areas, we stack P‐to‐s receiver functions to image the 410‐km and 660‐km discontinuities. Mantle transition zone (MTZ) thickening observed in a continuous area is attributable to ancient slab remnants, and Cenozoic volcanisms in the peripheral area can be explained by slab dehydration. The thinning of the MTZ in the Tuva‐Mongolian Massif can be explained by mantle upwelling branches induced by slab subduction. Our results reveal an approximately circular area in the MTZ that is significantly thicker than usual, suggesting the presence of detached mantle lithosphere in the form of a lithospheric drip extending to the MTZ. The presence of the drip is consistent with geochemical and lithospheric thickness observations, and the drip could be triggered by passage of a mantle plume currently located beneath western Lake Baikal.
Observations from the Little Bunker
Last updated: August 18, 2025 04:13 PM
Atmospheric CO₂
425.4 ppm
+18.4
ppm/year
Atmospheric CH₄
1934.91 ppb
+9.11
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year