Mineral physics constraints on the chemical composition and temperature of the earth’s mantle
department or school: Science, Faculty of
department or school: Earth, Ocean and Atmospheric Sciences, Department of
data provider: DSpace
degree campus: UBCV
creator: Calderwood, Arthur Robertson
issued: 2009-07-28T19:06:13Z
issued: 2000
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Numerical mineral physics modeling is used in seven studies to constrain the composition and dynamics of the Earth's mantle. First, using updated, published experimental data, I evaluate two competing mineralogical models for the composition of the mantle by calculating and comparing one dimensional profiles of density (ρ) and bulk sound velocity (V[sub Φ]) against seismologically inferred profiles. I find that the mineralogy of a uniform bulk composition provides an excellent fit to the seismic properties of the whole mantle along a self-consistent adiabatic geotherm which lacks any thermal boundary layers internal to the mantle. In contrast, the mineralogy of a chemically layered bulk composition results in predicted profiles which cannot satisfy the observations. Second, to further test the predicted properties of the uniform composition, pyrolite model, the mineral physics calculations are extended to predict one dimensional profiles of shear (V[sub S]) and compression (V[sub P]) velocity across the upper mantle and transition zone. Previous studies that modeled V[sub S] and V[sub P] suffered from having to estimate many of the necessary temperature and pressure derivatives required in the calculations and hence, the results were ambiguous. Fortuitously, many of these critical material properties (μ, (მμ/მT)[sub P,] (მμ/მP)[sub T],) are now experimentally measured and this study incorporates the latest results. I find that the predicted profiles of V[sub S] and V[sub P] are in excellent agreement in terms of both velocity gradient and absolute velocity with the latest, high-resolution regional seismic profiles. The predicted mineral physics profiles also give a mutually consistent estimate of the olivine content of the mantle from the velocity jumps at the 410 km seismic discontinuity. Lastly, the predicted V[sub S] and V[sub P] normalincidence reflectivity of the 410 km, 520 km and 660 km discontinuities matches a number of independent seismic estimates. Third,…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/11389
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note: Mineral Physics constraints on the Chemical Composition Temperature of the Earth's mantle By Arthur Robertson Calderwood B. Sc. Hon. (Geological Sciences) University of British Columbia M.Phil. (Geology and Geophysics) Yale University A THESIS SUBMITTED IN PARTIAL F U L F I L L M E N T OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE F A C U L T Y OF G R A D U A T E STUDIES E A R T H A N D O C E A N SCIENCES - G E O L O G Y We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH C O L U M B I A 1999 © Arthur Robertson Calderwood, 1999 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of / f e s S ^ / fhv)? tVsx&W £*G/J&&CS The University of British Columbia Vancouver, Canada DE-6 (2/88) Abstract Numerical mineral physics modeling is used in seven studies to constrain the composition and dynamics of the Earth's mantle. First, using updated, published experimental data, I evaluate two competing mineralogical models for the composition of the mantle by calculating and comparing one dimensional profiles of density (p) and bulk sound velocity (T 0) against seismologically inferred profiles. I find that the mineralogy of a uniform bulk composition provides an excellent fit to the seismic properties of the whole mantle along a self-consistent adiabatic geotherm which lacks any thermal boundary layers internal to the mantle. In contrast, the mineralogy of a chemically layered bulk composition results in predicted profiles which cannot satisfy the observations. Se…
has type: Thesis/Dissertation
date issued: 2000-05
is shown at: 10.14288/1.0052857
language: eng
degree discipline: Geological Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/11389