雄安新区壳幔结构揭示的大陆岩石圈改造模式

Based on a newly developed AI-based method for extracting teleseismic Rayleigh wave dispersion curves by Y. R. Jiang, a large volume of high-quality teleseismic Rayleigh wave dispersion curves was obtained from very broadband dense seismic observation data collected by J. Y. Ning team from October 2022 to July 2023 with station spacing of approximately 16 km. Phase velocity imaging considering finite-frequency effects and S-wave velocity inversion based on the nonlinear Markov Chain Monte Carlo technique were conducted, yielding a S-wave velocity structure of the crust and mantle in the Xiong’an New District. The S-wave velocity structure indicates that the lower crust beneath the Taihang Mountains is in direct contact with asthenosphere, while a relatively thin lithospheric mantle exists beneath the North China Plain to the southeast of Taihang Mountains. The crust in the Taihang Mountains and its southeast adjacent area shows differences in the presence or absence of a thick mafic lower crust. The fault zone at the front of the Taihang Mountains has been the core area for the ascent of mantle thermal material, leading to the foundering of the ancient lithosphere since the Late Mesozoic. Since the Cenozoic, the region has undergone a tectonic process of lithospheric extension and cooling. This study also proposes a dynamic model for the high heat flow in the Xiong’an New District.