The funnel-shaped crustal architecture in central Tibet and its insights into the progression of lithospheric removal

Central Tibet is a critical area for researching the profound lithospheric interactions between the Indian and Eurasian plates. Despite considerable interest in the area, exploring crustal responses at significant depths in the region proves challenging due to its high elevation. We carried out a 220-km-long deep seismic reflection survey in central Tibet. The seismic profile unveils distinct mid-to-lower crustal features displaying concave-upward patterns. The consistent geometry identified at the Moho emphasizes an overall funnel-shaped crustal configuration, indicating localized shortening. This unique architecture, coupled with the sustained compression from the advancing Indian lithosphere, outlines the initial funnel-shaped crustal structure of central Tibet predating the Eocene, potentially initiating gravitational instability leading to lithospheric dripping. Subsequently, delamination evolved, driven by continuous compression from the advancing Indian lithosphere and increased upper-mantle heat flow post-lithospheric dripping, potentially facilitating crustal separation. The concentrated high geothermal gradient beneath central Tibet, along with the northward migration of surface volcanism and uplift, elucidates the delamination process.