"The Australian continent is composed the of Precambrian cratons in the west and Phanerozolc orogens in the east. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Australia. In this study, we used two techniques, receiver functions and shear wave splitting analyses, to investigate the topography of the mantle transition zone (MTZ) discontinuities and mantle seismic azimuthal anisotropy, respectively. We utilized P-to-S receiver functions to map the 410 and 660 km discontinuities bordering the MTZ. The discontinuity depths obtained show a systematic apparent uplifting for both discontinuities in central and western Australia. The abnormally thick MTZ beneath eastern Australia can be adequately explained by subducted cold slabs in the MTZ. A localized normal thickness of the MTZ beneath the Newer Volcanics Province provides supporting evidence of a non-mantle-plume origin for the intraplate volcanic activities. Application of the shear wave splitting technique revealed systematic spatial variations of seismic azimuthal anisotropy. The South Australian Craton and the orogenic belt north of it possess strong E-W oriented lithospheric anisotropy, while absolute plate motion (APM) induced N-S oriented anisotropy dominates in the North Australian Craton. The western, southern, and eastern margins of the continent are dominated by root-deflected mantle flow. The relative strength and approximate orthogonality of the APM induced anisotropy and frozen-in lithospheric fabrics provide a viable explanation for the puzzling observation of pervasive existence of weak and spatially variable azimuthal anisotropy in this fast-moving continent"--Abstract, page iv.
Gao, Stephen S.
Liu, Kelly H.
Geosciences and Geological and Petroleum Engineering
Ph. D. in Geology and Geophysics
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Receiver function imaging of the 410 and 660 km discontinuities beneath the Australian continent
- Seismic azimuthal anisotropy beneath Australia from shear wave splitting analyses
xii, 86 pages
© 2021 Kailun Ba, All rights reserved.
Dissertation - Open Access
Electronic OCLC #
Ba, Kailun, "Receiver function imaging of the 410 and 660 km discontinuities and seismic azimuthal anisotropy revealed by shear wave splitting beneath the Australian continent" (2021). Doctoral Dissertations. 2998.