Doctoral Dissertations

Keywords and Phrases

Computational Geophysics; Earthquake; Mantle Transition Zone; Seismology

Abstract

"Investigating the depth of mantle transition zone (MTZ) discontinuities provides insights into mantle dynamics, including regional-scale downwelling of mantle lithosphere (i.e., lithospheric drip) and upwelling of thermal materials (i.e., mantle plume). In our study, we employ receiver functions to image the 410 km (d410) and 660 km (d660) mantle discontinuities and to ascertain thickness of the MTZ beneath Central Asia and the Great Plains in United States. The findings unveil a significantly thickened transition zone, exhibiting an average thickness of 284 km beneath East Sayan. When considered alongside geochemical observations, our results indicate that the descent of the lithosphere is induced by the interaction between hot mantle plumes and the base of the lithosphere. The thinner-than-normal transition zone underneath the surrounding area is likely due to the upward movement of small-scale mantle convection, which is initiated by the formation of a lithospheric drip. Additionally, the MTZ complexity model is utilized to detect attenuation of amplitude in the MTZ under the southern Great Plains and band-pass filters with various frequency bands are applied to evaluate the robustness and resolution of the results. The thinning the transition zone thickness and simple structure indicate the existence of a thermal anomaly within the MTZ beneath the region. Integrated with tomographic observations, the presence of a deep-seated mantle plume originating from the lower mantle, which is deflected at the MTZ beneath the southern Great Plains due to eastward density-driven flow. This mantle plume subsequently ascends along the base of the lithosphere and provides source for Raton hotspot" -- Abstract, p. iv

Advisor(s)

Gao, Stephen S.
Liu, Kelly H.

Committee Member(s)

Cawlfield, Jeffrey D.
Smith, Ryan G.
Mickus, Kevin L.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2024

Pagination

x, 93 pages

Note about bibliography

Includes_bibliographical_references_(pages 40, 87 & 92)

Rights

©2024 Yangyang Liao , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12393

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