Doctoral Dissertations

Author

Kailun Ba

Abstract

"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.

Advisor(s)

Gao, Stephen S.
Liu, Kelly H.

Committee Member(s)

Yang, Wan
Obrist-Farner, Jonathan
Song, Jianguo

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Comments

The study benefitted from award MRI-1919789 of the United States National Science Foundation to S.G., and award titled “Building research capacity for geospatial-enabled data-driven discoveries” from the University of Missouri System to S.G.

The study is supported by the National Science Foundation under grants 1460516 and 1830644 to K.L. and S.G.

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2021

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

Pagination

xii, 86 pages

Note about bibliography

Includes bibliographic references.

Geographic Coverage

Australia

Rights

© 2021 Kailun Ba, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11892

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