Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables

This thesis focuses on interpreting geophysical and geochemical observables in terms of the thermomechanical state of the lithosphere. In Chapter 1, I correlate lower crustal rheology with seismic wave speed. Compositional variation is required to explain half of the total variability in predicted l...

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Main Author: Shinevar, William Joseph
Other Authors: Jagoutz, Oliver
Format: Thesis
Published: Massachusetts Institute of Technology 2022
Online Access:https://hdl.handle.net/1721.1/139930
https://orcid.org/0000-0001-6384-8023
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author Shinevar, William Joseph
author2 Jagoutz, Oliver
author_facet Jagoutz, Oliver
Shinevar, William Joseph
author_sort Shinevar, William Joseph
collection MIT
description This thesis focuses on interpreting geophysical and geochemical observables in terms of the thermomechanical state of the lithosphere. In Chapter 1, I correlate lower crustal rheology with seismic wave speed. Compositional variation is required to explain half of the total variability in predicted lower crustal stress, implying that constraining regional lithology is important for lower crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic collapse. In Chapter 3, I interpret geophysical data along a 74 Myr transect in the Atlantic to the temporal variability and relationship of crustal thickness and normal faults. In Chapter 4, I constrain the error present in the forward-calculation of seismic wave speed from ultramafic bulk composition. I also present a database and toolbox to interpret seismic wave speeds in terms of temperature and composition. Finally, in Chapter 5 I apply the methodology from Chapter 4 to interpret a new seismic tomographic model in terms of temperature, density, and composition in order to show that the shallow lithospheric roots are density unstable.
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spelling mit-1721.1/1399302022-02-08T03:01:47Z Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables Shinevar, William Joseph Jagoutz, Oliver Behn, Mark D. Joint Program in Marine Geology and Geophysics Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences This thesis focuses on interpreting geophysical and geochemical observables in terms of the thermomechanical state of the lithosphere. In Chapter 1, I correlate lower crustal rheology with seismic wave speed. Compositional variation is required to explain half of the total variability in predicted lower crustal stress, implying that constraining regional lithology is important for lower crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic collapse. In Chapter 3, I interpret geophysical data along a 74 Myr transect in the Atlantic to the temporal variability and relationship of crustal thickness and normal faults. In Chapter 4, I constrain the error present in the forward-calculation of seismic wave speed from ultramafic bulk composition. I also present a database and toolbox to interpret seismic wave speeds in terms of temperature and composition. Finally, in Chapter 5 I apply the methodology from Chapter 4 to interpret a new seismic tomographic model in terms of temperature, density, and composition in order to show that the shallow lithospheric roots are density unstable. Ph.D. 2022-02-07T15:13:24Z 2022-02-07T15:13:24Z 2021-09 2021-10-19T13:40:39.795Z Thesis https://hdl.handle.net/1721.1/139930 https://orcid.org/0000-0001-6384-8023 In Copyright - Educational Use Permitted Copyright MIT http://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Shinevar, William Joseph
Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title_full Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title_fullStr Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title_full_unstemmed Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title_short Inferring the Thermomechanical State of the Lithosphere Using Geophysical and Geochemical Observables
title_sort inferring the thermomechanical state of the lithosphere using geophysical and geochemical observables
url https://hdl.handle.net/1721.1/139930
https://orcid.org/0000-0001-6384-8023
work_keys_str_mv AT shinevarwilliamjoseph inferringthethermomechanicalstateofthelithosphereusinggeophysicalandgeochemicalobservables