Regional differences in crustal structure of the North China Craton from receiver functions

Abstract

Moho depth and crustal average Poisson's ratio for 823 stations are obtained by H- stacking of receiver functions. These, together with topography and receiver function amplitude information, were used to study the crustal structure beneath the North China Craton (NCC). The results suggest that modified and preserved crust coexist beneath the craton with generally Airy-type isostatic equilibrium. The equilibrium is relatively low in the eastern NCC and some local areas in the central and western NCC, which correlates well with regional geology and tectonic features. Major differences in the crust were observed beneath the eastern, central, and western NCC, with average Moho depths of 33, 37, and 42 km and average Poisson's ratios of 0.268, 0.267 and 0.264, respectively. Abnormal Moho depths and Poisson's ratios are mainly present in the rift zones, the northern and southern edges of the central NCC, and tectonic boundaries. The crust beneath Ordos retains the characteristics of typical craton. Poisson's ratio increases roughly linearly as Moho depth decreases in all three parts of the NCC with different slopes. Receiver function amplitudes are relatively large in the northern edge of the eastern and central NCC, and small in and near the rifts. The Yanshan Mountains and southern part of the Shanxi rift show small-scale variations in the receiver-function amplitudes. These observations suggest that overall modification and thinning in the crust occurred in the eastern NCC, and local crustal modification occurred in the central and western NCC. Different crustal structures in the eastern, central, and western NCC suggest different modification processes and mechanisms. The overall destruction of the crustal structure in the eastern NCC is probably due to the westward subduction of the Pacific Plate during the Meso-Cenozoic time; the local modifications of the crust in the central and western NCC may be due to repeated reactivations at zones with a heterogeneous structure by successive thermal-tectonic events during the long-term evolution of the NCC.North China Craton, Moho depth, Poisson's ratio, gravitational equilibrium, receiver function amplitude, regional difference in crust Citation:

Origin, Accretion, and Reworking of Continents

“…This explains the sharp differences in both tectonic processes (e.g., F. Y. Xu, 2001;Zhu et al, 2011) and structure from the surface to the base of the lithosphere between the eastern and central-western NCC (Figure 26;Chen, 2010;Wei et al, 2015;Xu et al, 2018;Zheng et al, 2017), and may also be responsible for the similar observations across the boundaries of distinctly different structures and/or deformation in western North America, including the Wyoming craton (Figure 16a,b). The scenario proposed in Figure 27b is consistent with the observed similar depths of the MLD in stable cratonic regions and the LAB in adjacent destroyed cratonic parts or tectonic regions (Figure 24, Chen, 2017;Thybo, 2006, and references therein).…”

“…That means that craton destruction would be temporarily and spatially ZHU ET AL. Wei et al (2015Wei et al ( , 2016; panel (b) is modified from Y. . The crustal and upper mantle velocity models in panel (c) are from Zheng et al (2017) and Xu et al (2018), respectively.…”

“…Depth distributions of the Moho (a) and the LAB (b) in the North China Craton (NCC) and crustal and upper mantle P-wave velocity structure together with altitude along 37°N latitude across the craton (c), showing large differences in crustal and lithospheric thickness and structure and topography as well between the eastern NCC (ENCC) and the central (CNCC or TNCO)-western NCC (WNCC). The Moho depth data used in panel (a) are fromWei et al (2015Wei et al ( , 2016; panel (b) is modified from Y.. The crustal and upper mantle velocity models in panel (c) are fromZheng et al (2017) andXu et al (2018), respectively.…”

Reworking of ancient tectonic amalgamation belt beneath the central north of North China Craton revealed by dense seismic observations

“…The subduction-collision-exhumation events of Paleoproterozoic orogenic tectonic development transported these high-pressure granulites and eclogites into the core crust (Zhang et al, 2019).Geophysical methods can effectively understand the current deep structures and the Frontiers in Earth Science frontiersin.org tectonic processes. Several scholars have reported the strong concordance of surface topographic changes in the area and the E-W variations in the crustal and lithospheric structures (e.g., Chen, 2010;Cheng et al, 2013;Wei et al, 2015;Zheng et al, 2017). NCC and several other cratons in the world have restructured as a result of subduction (Zhu et al, 2021), and the pre-existing structures in the lithosphere primarily control such continental reconfiguration.…”

Tectonic Implication of the 2022 MS 6.9 Earthquake in Menyuan, Qinghai, China: Analysis of Precise Earthquake Locations and InSAR

“…The one-dimensional velocity model is often used for seismic positioning, but the criteria and methods for selecting the model are different: the one-dimensional velocity model obtained by others is directly quoted or slightly adjusted [ 4 , 5 , 6 ], or inversion based on the existing velocity model to obtain a one-dimensional velocity model [ 7 ]. Due to the regional differences of geological structures, the one-dimensional velocity models in different regions are quite different, so it is necessary to conduct targeted case analysis on specific cases [ 8 ]. The accuracy of seismic positioning is highly dependent on the velocity model.…”