Seismic crustal structure of the North China Craton and surrounding area: Synthesis and analysis. Issue 7 (11th July 2017)

• Record Type: Journal Article
• Authors: Xia, B.; Thybo, H.; Artemieva, I. M.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 7(2017)
• Page Start: 5181
• Page End: 5207
• Publication Date: 2017-07-11
• Subjects: seismic crust structure -- Moho depth -- crustal thickness -- Pn velocity -- topography versus Moho depth -- North China Craton; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1002/2016JB013848
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: We present a new digital model (NCcrust) of the seismic crustal structure of the Neoarchean North China Craton (NCC) and its surrounding Paleozoic‐Mesozoic orogenic belts (30°–45°N, 100°–130°E). All available seismic profiles, complemented by receiver function interpretations of crustal thickness, are used to constrain a new comprehensive crustal model NCcrust. The model, presented on a 0.25° × 0.25°grid, includes the Moho depth and the internal structure (thickness and velocity) of the crust specified for four layers (the sedimentary cover, upper, middle, and lower crust) and the P n velocity in the uppermost mantle. The crust is thin (30–32 km) in the east, while the Moho depth in the western part of the NCC is 38–44 km. The Moho depth of the Sulu‐Dabie‐Qinling‐Qilian orogenic belt ranges from 31 km to 51 km, with a general westward increase in crustal thickness. The sedimentary cover is 2–5 km thick in most of the region, and typical thicknesses of the upper crust, middle crust, and lower crust are 16–24 km, 6–24 km, and 0–6 km, respectively. We document a general trend of westward increase in the thickness of all crustal layers of the crystalline basement and as a consequence, the depth of the Moho. There is no systematic regional pattern in the average crustal V p velocity and the P n velocity. We examine correlation between the Moho depth and topography for seven tectonic provinces in the North China Craton and speculate on mechanisms of isostatic compensation. Key Points: A new model of seismic crustal structure of the North China Craton Westward increase in thickness of all crustal layers, with no trend for average V p and the P n velocities Topography in this region is mostly controlled by the crustal heterogeneity