Seismic and numerical constraints on the formation and evolution of ocean lithosphere

This thesis explicates aspects of the basic structure of oceanic lithosphere that are shaped by the processes that form the lithosphere. The strength of lithospheric plates relative to the underlying mantle enables the surface plate motions and plate boundary processes that characterize plate tectonics on Earth. Surprisingly, we have a relatively poor understanding of the physical mechanisms that make the lithosphere strong relative to the asthenosphere, and we lack a reference model for ordinary lithospheric structure that can serve as a baseline for comparing geophysical observations across locations. Chapters 2 and 3 of this thesis investigate the seismic structure of a portion of the Pacific plate where the simple tectonic history of the plate suggests that its structure can be used as a reference model for oceanic lithosphere. We present measurements of shallow azimuthal seismic anisotropy, and of a seismic discontinuity in the upper mantle, that reflect the effects of shear deformation and melting processes involved in the formation of the lithosphere at mid-ocean ridges. Chapter 4 uses numerical models to explore factors controlling fault slip behavior on normal faults that accommodate tectonic extension during plate formation.

Name thesis:degree_name

Doctoral

Department dc:contributor.department

Joint Program in Oceanography/Applied Ocean Science and Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2019

Author dc:creator

• Mark, Hannah F.

Advisor dc:contributor.advisor

• Daniel Lizarralde.

• Joint Program in Oceanography/Applied Ocean Science and Engineering.
• Earth, Atmospheric, and Planetary Sciences.
• Woods Hole Oceanographic Institution.

Statement dc:rights

• MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/127722

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/127722