Lithospheric Structure and Evolution of Southern Africa: Constraints From Joint Inversion of Rayleigh Wave Dispersion and Receiver Functions

Wang, Tuo1; Gao, Stephen S.1; Dai, Yuhang2; Yang, Qiuyue1; Liu, Kelly H.1

2019-07

10.1029/2019GC008259

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS   影响因子和分区

1525-2027

We conduct a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion from both ambient noise and earthquakes using data from 79 seismic stations in southern Africa, which is home to some of the world's oldest cratons and orogenic belts. The area has experienced two of the largest igneous activities in the world (the Okavango dyke swarm and Bushveld mafic intrusion) and thus is an ideal locale for investigating continental formation and evolution. The resulting 3-D shear wave velocities for the depth range of 0-100km and crustal thickness measurements show a clear spatial correspondence with known geological features observed on the surface. Higher than normal mantle velocities found beneath the southern part of the Kaapvaal craton are consistent with the basalt removal model for the formation of cratonic lithosphere. In contrast, the Bushveld complex situated within the northern part of the craton is characterized by a thicker crust and higher crustal V-p/V-s but lower mantle velocities, which are indicative of crustal underplating of mafic materials and lithospheric refertilization by the world's largest layered mafic igneous intrusion. The thickened crust and relatively low elevation observed in the Limpopo belt, which is a late Archean collisional zone between the Kaapvaal and Zimbabwe cratons, can be explained by eclogitization of the basaltic lower crust. The study also finds evidence for the presence of a stalled segment of oceanic lithosphere beneath the southern margin of the Proterozoic Namaqua-Natal mobile belt.

Kaapvaal craton Limpopo belt ambient noise tomography lithosphere continental crust

SCI ; EI

英语

其他

U.S. National Science Foundation[1009946] ; U.S. National Science Foundation[1321656]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000480282600012

AMER GEOPHYSICAL UNION

20192907181376

Acoustic noise ; Dispersion (waves) ; Earthquakes ; Rayleigh waves ; Shear waves ; Structural geology ; Thickness measurement ; Velocity

Geology:481.1 ; Seismology:484 ; Fluid Flow, General:631.1 ; Acoustic Noise:751.4 ; Mechanics:931.1 ; Mechanical Variables Measurements:943.2

GEOSCIENCES

Web of Science

1.Missouri Univ Sci & Technol, Geol & Geophys Program, Rolla, MO 65409 USA
2.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen, Peoples R China

Wang, Tuo,Gao, Stephen S.,Dai, Yuhang,et al. Lithospheric Structure and Evolution of Southern Africa: Constraints From Joint Inversion of Rayleigh Wave Dispersion and Receiver Functions[J]. GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,2019,20(7):3311-3327.

Wang, Tuo,Gao, Stephen S.,Dai, Yuhang,Yang, Qiuyue,&Liu, Kelly H..(2019).Lithospheric Structure and Evolution of Southern Africa: Constraints From Joint Inversion of Rayleigh Wave Dispersion and Receiver Functions.GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,20(7),3311-3327.

Wang, Tuo,et al."Lithospheric Structure and Evolution of Southern Africa: Constraints From Joint Inversion of Rayleigh Wave Dispersion and Receiver Functions".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 20.7(2019):3311-3327.