New JGR paper in press: Moho depth variations from receiver function imaging in the Northeastern North China Craton and its tectonic implications
Moho depth variations from receiver function imaging in the Northeastern North China Craton and its tectonic implications
Ping Zhang1, Huajian Yao1,2, Ling Chen3,4,5, Lihua Fang6, Yan Wu6, Jikun Feng1
1Laboratory of Seismology and Physics of Earth’s Interior & School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
2CAS Center for Excellence in Comparative Planetology, Hefei 230026, China
3Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 10029, China.
4CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 10029, China.
5University of Chinese Academy of Sciences, Beijing 10049, China.
6Institute of Geophysics, China Earthquake Administration, Beijing 10081, China.
Key Points:
1. A high-resolution Moho depth map in the northeastern North China Craton was derived by receiver function imaging.
2. Significant N-S variations in the Moho depth are presented on both sides of the North-South Gravity Lineament.
3. N-S structural variations may have resulted from a series of tectonic events over long-term evolution of the North China Craton.
Abstract: A detailed knowledge of the crustal thickness in the northeastern North China Craton (NCC) is important for understanding the unusual Phanerozoic destruction of the craton. We achieve this goal by employing a 2-D wave equation-based migration method to P receiver functions from 198 broadband seismic stations, using Ps conversions and surface-reflected multiples. By combining receiver function images along 19 profiles, we constructed a high-resolution Moho depth model for the northeastern NCC. The results present dominant E-W Moho depth variations similar to previous observations and new regional N-S variations beneath both sides of the North-South Gravity Lineament. To the west, while a deeper Moho (∼42 km) appears in the interior of the Trans-North China Orogen (TNCO), a relatively shallow Moho (∼38) exists in the northern margin of the TNCO to western NCC. To the east, the crust beneath the Yan Mountains in the marginal area is thicker (∼32-40 km) than that (∼26-32 km) beneath the Bohai Bay Basin in the craton interior, and the Moho further shallows from NE (∼32 km) to SW (∼26 km) within the basin. Along with other observations, we conclude that the dominant E-W difference may have been associated with the Paleo-Pacific plate subduction under eastern Asia since the Mesozoic. The newly observed complex N-S variations may have reflected the structural heterogeneity of the cratonic lithosphere inherited since the formation of the NCC in the Paleoproterozoic, or spatially uneven effects on the cratonic lithosphere of subsequent thermotectonic events during the long-term evolution of the craton, or both.
