Three‐Dimensional Crustal Structures of the Shanxi Rift Constructed by Rayleigh Wave Dispersion Curves and Ellipticity: Implication for Sedimentation, Intraplate Volcanism, and Seismicity

Abstract

The Shanxi Rift is one of the world's largest Cenozoic continental rifts. It is one of the most earthquake prone areas in China and has volcanic activities characterized by small volumes of magma. In order to study continental rifting mechanism, intraplate volcanism, and seismicity of the Shanxi Rift, we construct a high-resolution 3-D lithospheric shear velocity (Vs) model with a focus of the crust by jointly inverting Rayleigh wave dispersion curves and ellipticity measurements. Compared with published models, our 3-D Vs model has improved the resolution for shallow structures. Our model reveals several significant velocity features. (1) The sedimentary layer of the Datong Basin is much thicker than those in the southern Shanxi Rift, implying that the sedimentation rate of the Datong Basin is higher, which could be attributed in part to asthenosphere upwelling beneath the Datong Basin area in the past few Ma in addition to passive rifting. (2) A low-velocity body is observed in the middle crust beneath the Datong Volcanoes, suggesting the presence of a small amount of partial melting in the middle crust. (3) Lower velocities in the middle and lower crust beneath the Datong Basin are coincident with the shallowing of deep earthquakes from the southern to northern Shanxi Rift in the crust, suggesting that higher temperature may elevate the brittle-to-ductile transition zone, leading to the shallowing of focal depths of earthquakes in the Shanxi Rift from south to north.

Vestiges of underplating and assembly in the central North China Craton based on S-wave velocities

“…We also detect a cylindrical high-velocity anomaly at 9–38 s (Fig. 3 , HV) near Datong volcanic group 40 and located within Cenozoic basalt region 41 in the TNCO. Generally, basalts are generated by the upwelling of mafic magmatic material along cylindrical columns from the bottom of the lower crust 42 .…”

Nutrient composition and functional constituents of daylily from different producing areas based on widely targeted metabolomics

“…However, different growing environments significantly affect the quality of plants (vegetables or herbs) ( Gao et al, 2021 ). In particular, the average annual temperature in different regions of Shanxi Province increases from the north to the south and decreases from the basins to the high mountains ( Xu et al, 2020 ). Precipitation is also distributed differently across the Shanxi province, depending on topography.…”

Seismic Imaging of a Magma Chamber and Melt Recharge of the Dormant Datong Volcanoes

“…The Datong volcanic eruption took place within several life-cycles from 0.74 to 0.10 Ma with a relatively consistent repose interval of ∼0.2-0.3 Ma (Zhai et al, 2011), which is almost a longest end-member in terms of repose time. Although the Datong volcanoes are commonly known as dormant without any apparent volcanic activities at present, seismic images from surface wave (Li et al, 2018;Xu et al, 2020) and teleseismic body wave (Lei, 2012) tomography revealed a low velocity anomaly in the upper mantle beneath the Datong volcanoes. A recent magnetotelluric study revealed significant middle crustal conductors, which may indicate the presence of crustal magma bodies (Zhang et al, 2016).…”