Author ORCID Identifier

https://orcid.org/0000-0003-2115-0203

Year of Publication

2021

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Arts and Sciences

Department/School/Program

Earth and Environmental Sciences (Geology)

First Advisor

Dr. Keely Anne O'Farrell

Abstract

Subduction zones form as higher density oceanic lithosphere is forced beneath an over-riding, lower density, continental or oceanic plate; a process driven by contrasts in buoyancy throughout this system. We seek to explore subduction zones in which the subducting lithosphere is discontinuous after passing through the trench, forming a slab gap. The main research objective is to determine the effect of slab gaps on surface topography in a subduction-related orogen and asthenospheric flow into the mantle wedge using two and three-dimensional numerical mechanical models. We obtain results from 24+ models that suggest a connection between slab gaps/holes and the magnitude and trend of topography produced during the first several million years of subduction. Two-dimensional models suggest there may be flow into slab gaps and tears, affecting mantle flow around the slab and producing less topography in the orogen. Three-dimensional models suggest the opposite is true, with larger slab gaps/holes producing less surface topography above the gap. The three-dimensional models also suggest that subduction-related orogens may have associated curvature above regions where slab gaps are present. This work shows new ways to test for the potential slab gaps/holes in subduction zones by looking at flow fields, surface topography, and orogenic/slab curvature.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.236

Funding Information

This study was supported by the University of Kentucky Earth and Environmental Sciences Ferm Student Research Support in 2020.

This study was also supported by the University of Kentucky Earth and Environmental Sciences Brown-McFarland Fund in 2020.

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