Imaging the crustal structure beneath the Yinchuan Basin in the western North China Craton using normalized full gradient and 3D gravity inversion

Abstract The crustal structure beneath the United Arab Emirates (UAE) is still relatively unknown. Here, we use regional gravity data to constrain the subsurface density distribution and structure of the crust of the UAE by applying diverse gravity derivatives methods such as horizontal derivative (HDR), analytic signal (AS), and tilt angle (TA) to analyze the subsurface structure and perform three-dimensional (3D) gravity inversion for imaging crustal structure from the surface down to 35 km depth. The results are compared with known geological regional structures and the location of the petroleum fields. The Bouguer anomalies range from −100.8 to 113.5 mGal. The 3D gravity inversion results and the maximum Bouguer values coincide with the ophiolitic Hajar mountains in the east and the successive anticlines (uplifted basement rocks) and synclines in different parts of UAE, which could be promising sites for future mining and petroleum exploration. Also, the 3D density model results and the minimum Bouguer anomalies are located over the Aruma Basin, eastern UAE Platform, and Low Central UAE Platform, which can be the places for deep groundwater aquifers. These new results from HDR, AS, and TA successfully identify known geological structures, especially in the eastern part of UAE.

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SEISMIC CRUSTAL STRUCTURE OF THE NORTH CHINA CRATON AND SURROUNDING AREA: SYNTHESIS AND ANALYSIS

10.1130/abs/2016am-280294 ◽

2016 ◽

Author(s):

Bing Xia ◽

◽

Hans Thybo ◽

Irina M. Artemieva

Keyword(s):

Crustal Structure ◽

North China Craton ◽

North China ◽

Surrounding Area ◽

The North

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

Scientific Reports ◽

10.1038/s41598-021-00756-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Haoyu Tian ◽

Chuansong He

Keyword(s):

Group Velocity ◽

Wave Velocity ◽

Crustal Structure ◽

North China Craton ◽

Lower Crust ◽

North China ◽

Velocity Structure ◽

S Wave ◽

Middle Crust ◽

Wave Velocities

AbstractThe destruction of the North China Craton (NCC) is a controversial topic among researchers. In particular, the crustal structure associated with the craton’s destruction remains unclear, even though a large number of seismic studies have been carried out in this area. To investigate the crustal structure and its dynamic implications, we perform noise tomography in the central part of the NCC. In this study, continuous vertical-component waveforms spanning one year from 112 broadband seismic stations are used to obtain the group velocity dispersion curves of Rayleigh waves at different periods, and surface wave tomography is employed to extract the Rayleigh wave group velocity distributions at 9–40 s. Finally, the S-wave velocity structure at depths of 0–60 km is determined by the inversion of pure-path dispersion data. The results show obvious differences in the crustal structure among the Western Block (WB), the Trans-North China Orogen (TNCO) and the Eastern Block (EB). The lower crust of the northern part of the EB exhibits a high-velocity S-wave anomaly, which may be related to magmatic underplating in the lower crust induced by an upwelling mantle plume. The S-wave velocity of the WB is lower than that of the TNCO in the upper and middle crust and is lower than that of both the TNCO and the EB in the lower crust. The crust of the TNCO shows higher S-wave velocities than the WB and EB in the upper and middle crust, and its overall S-wave velocity structure is clearly different from those of the WB and EB, implying that the crustal structure of the TNCO may contain vestiges of the Paleoproterozoic collision between the WB and EB and their subsequent assembly. This study marks the first time these findings are identified for the NCC.

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