Moho Depth Variations From Receiver Function Imaging in the Northeastern North China Craton and Its Tectonic Implications

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, a relatively shallow Moho (∼38 km) exists in the northern margin of the Trans‐North China Orogen 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.

Receiver Function Velocity Analysis Technique and Its Application to Remove Multiples

“…Along the BB′ line, the corresponding values were 37.54 km, 6.63 km/s, and 3.86 km/s. CCP images show that the Moho gradually deepens from east to west (Figures 9a and 9c) and from south to north (Figures 9b and 9d), consistent with the findings of previous studies (Chen et al, 2009;Zhang, Yao, et al, 2019;Zheng et al, 2007). E-W trending crustal changes may be related to the subduction of the Paleo-Pacific Plate in the Mesozoic (Zhu et al, 2011), whereas S-N trending crustal changes may reflect S-N compressional deformation dating to the Jurassic and early Cretaceous (Davis et al, 2001;Meng, 2003).…”

Seismic Imaging of the Subducted Australian Continental Margin Beneath Timor and the Banda Arc Collision Zone

“…Conversions are primarily sensitive to changes in the Vs structure and depend weakly on the crustal Vp structure, whereas high‐frequency reflections (autocorrelation traces) provide high resolution of crustal Vp reflectors (e.g., sharp Moho). Reverberations from shallow low‐velocity layers (e.g., sediment or intracrustal anomaly) potentially interfere with Ps conversions but converted multiples (i.e., PpPs and PsPs + PpSs) and reflection phases (e.g., PpPp) can provide more robust images in these settings (e.g., Phạm & Tkalčić, 2017, 2018; Zhang et al., 2019). The influence of the source and path effects and simultaneous arrivals of multiple orders of reverberations have been a fundamental challenge in interpreting the autocorrelograms (e.g., Phạm & Tkalčić, 2017).…”

Phanerozoic Evolution of Lithospheric Structures of the North China Craton

“…The present crustal thickness (Feng et al, 2017;Y. H. Li et al, 2014;Han, 2020;P. Zhang et al, 2019) (Figure 2a) and lithospheric thickness (Y.…”

“…We chose the core area of the NCC extending from 108° to 118° in longitude and from 34° to 40°N in latitude (Figure 1) to investigate the spatiotemporal variations in deformation since the Paleozoic and when the lithospheric structures were still stable. The present crustal thickness (Feng et al., 2017; Y. H. Li et al., 2014; Han, 2020; P. Zhang et al., 2019) (Figure 2a) and lithospheric thickness (Y. Zhang et al., 2019) (Figure 2b) were constructed from P‐wave and S‐wave receiver functions at 1,732 stations. The current Moho temperature was obtained from a previous study (K. Wang et al., 2020) and presented in Figure 2c.…”

“…However, recent studies show that significant parts of the NCC lithosphere have been modified. In particular, the lithosphere of EB has been thinned to only ∼70 km (Y. Zhang et al., 2019), which is much thinner than the thickness of a typical cratonic lithosphere.…”