Doctoral Dissertations

Abstract

"Stacking of about 15,500 P-to-S receiver functions recorded at 72 USArray and other broadband seismic stations placed on the Colorado Plateau and the SBRP in Arizona revealed systematic spatial variations in crustal Vp/Vs, crustal thickness and amplitude of P-to-S converted phases. Our results reveal that the BRP is characterized by a thin crust (28.2 ± 0.5 km), a mean Vp/Vs of 1.761 ± 0.014 and a mean amplitude (R) of P - to - S converted wave (relative to that of the direct P wave) of 0.181 ± 0.014 that are similar to a typical continental crust, consistent with the model that the thin crust was the consequence of lithospheric stretching during the Cenozoic. The CP is characterized by the thickest crust (42.3 ± 0.8 km), largest Vp/Vs (1.825 ± 0.009) and smallest R (0.105 ± 0.007) values in the study area. The Colorado Plateau in the study area has the thickest crust and its southern part revealed two layers crustal structure having 12 km thickness of the lower layer. Crust beneath the southern Basin and Range Province is less mafic but thinner than normal continental. The simplest model for the observation is that the Colorado Plateau crust is underlain by a mafic layer which increases both the thickness and Vp/Vs, and decreases the amplitudes of the converted phases by reducing the velocity contrast between the crust and mantle. The results are in general agreement with previous studies (e.g. Frassetto et al., 2006; Gilbert et al., 2007). We hypothesize that the lower crustal layer, which has an anomalously large density as revealed by gravity modeling and high velocities in seismic refraction lines, contributed to the long-term stability and pre-uplift low elevation of the Colorado Plateau in the study area"--Abstract, page iv.

Advisor(s)

Gao, Stephen S.
Liu, Kelly H.

Committee Member(s)

Laudon, Robert C.
Abdel Salam, Mohamed G.
Anderson, Neil L. (Neil Lennart), 1954-

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Sponsor(s)

National Science Foundation (U.S.)
University of Missouri Research Board

Comments

Partial support by National Science Foundation awards EAR-0703359 and EAR-0952064

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2011

Journal article titles appearing in thesis/dissertation

Crustal structure and evolution beneath the Colorado Plateau and the southern basin and range province: results from receiver function and gravity studies

Pagination

ix, 131 pages, maps

Note about bibliography

Includes bibliographical references (pages 121-130).

Geographic Coverage

Earth
Colorado Plateau

Rights

© 2011 Lamuail Bashir, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Earth (Planet) -- Crust -- EvolutionColorado Plateau

Thesis Number

T 9892

Print OCLC #

795128163

Electronic OCLC #

909285915

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Dissertation Location

 
COinS