Abstract:
As a tectonic transfer and transition unit between the Yangtze Block and the eastern (southern) margin of the Tibetan Plateau, Daliangshan tectonic belt plays a pivotal role in accommodating the differential movements between the Chuandian block and the South China block. Its deep structure serves as the core for deciphering the deformation mechanisms underlying the southward expansion of crustal material in the Tibetan Plateau following the obstruction of its eastward escape. This paper systematically synthesizes existing research findings from multiple perspectives, including tectonic evolution history, block kinematic characteristics, seismicity, and geophysical deep structural exploration. In terms of tectonic evolution, the belt underwent a four-stage, multi-mechanism superimposed process from the Late Mesozoic to Cenozoic, controlled by multiple far-field dynamic sources such as the subduction of the Pacific Plate and the collision between the Indian and Eurasian Plates. Relative to the South China block, Daliangshan tectonic belt is generally dominated by counterclockwise rotation, with a multi-level strain transfer and adjustment system developed within it. Seismic activities are concentrated along the boundary fault zones, while seismicity within itself is weak. However, prominent seismic gaps and strongly locked segments are identified in fault zones such as the Anninghe-Zemuhe fault zone and the Daliangshan fault zone, implying their potential to generate strong earthquakes. Geophysical exploration of deep structures reveals distinct high-velocity and low-velocity anomalous zones in the crust, with significant differences in north-south trending tectonic deformation and stress field characteristics. The crustal material migration hindered by rigid blocks is likely to exhibit complex flowing paths. The research results provide additional scientific insights for investigating the dynamic uplift mechanism of the eastern (southern) margin of the Tibetan Plateau and assessing the potential risk of strong earthquakes in the region.