摘要
We present the 1-D crustal velocity structure of the major tectonic blocks of the North China Craton(NCC)along 36°N based on synthetic seismogram modeling of long-range wide-angle reflection/refraction data.This profile extends from southwest Yan’an of central Shaanxi Province of China(109.47°E),across the southern Trans-North China Orogen(TNCO),the southwestern part of the North China Plain(NCP),the Luxi Uplift(LU)and the Sulu Orogen(SLO),ending at Qingdao City of Shandong Province,the eastern margin of China(120.12°E)along 36°N.We utilized reflectivity synthetic seismogram modeling of the active source data to develop 1-D velocity structures of the sub-blocks of the NCC.Our final model shows that the NCC crust varies remarkably among the tectonic units with different velocity structure features.Higher lower crustal velocity and Moho depth^42 km is a major feature of the crust beneath southern Ordos Blockt.The TNCO which is composed of Lyuliangshan Mountains(LM),Shanxi Graben(SXG)and Taihangshan Mountains(TM)shows dominant trans-orogenic features.The NCP shows a dominant thickening of sediments,sharp crust thinning with Moho depth^32 km and significant lower average velocity.The SLO and the LU shows a stratified crust,higher average velocity and crust thinning with Moho depth of^35 km.Our model shows the coincidence between the deep structure and the surface geology among all the tectonic sub-blocks of the NCC.
We present the 1-D crustal velocity structure of the major tectonic blocks of the North China Craton(NCC) along 36°N based on synthetic seismogram modeling of long-range wide-angle reflection/refraction data. This profile extends from southwest Yan’an of central Shaanxi Province of China(109.47°E), across the southern Trans-North China Orogen(TNCO), the southwestern part of the North China Plain(NCP), the Luxi Uplift(LU) and the Sulu Orogen(SLO), ending at Qingdao City of Shandong Province, the eastern margin of China(120.12°E) along 36°N. We utilized reflectivity synthetic seismogram modeling of the active source data to develop 1-D velocity structures of the sub-blocks of the NCC. Our final model shows that the NCC crust varies remarkably among the tectonic units with different velocity structure features. Higher lower crustal velocity and Moho depth ～42 km is a major feature of the crust beneath southern Ordos Blockt. The TNCO which is composed of Lyuliangshan Mountains(LM), Shanxi Graben(SXG) and Taihangshan Mountains(TM) shows dominant trans-orogenic features. The NCP shows a dominant thickening of sediments, sharp crust thinning with Moho depth ～32 km and significant lower average velocity. The SLO and the LU shows a stratified crust, higher average velocity and crust thinning with Moho depth of ～35 km. Our model shows the coincidence between the deep structure and the surface geology among all the tectonic sub-blocks of the NCC.
基金
This project sponsored by the National Natural Science Foudation of China(NSFC)(41574084 and 41774071)
