Earth and Planetary Sciences ETDs

Publication Date

Spring 5-16-2026

Abstract

Deep-sea and convergent margin sedimentary systems preserve critical records of tectonic and climatic processes that shape Earth’s surface. This dissertation investigates source-to-sink sediment routing and forearc deformation to better constrain the interplay between sedimentary and tectonic processes, through investigations of a deep-sea fan system, and the forearc geomorphology offshore Nicaragua. In the Gulf of Alaska, we integrate ultra-long-offset and regional multi-channel seismic reflection data, multi-resolution bathymetry, and plate reconstructions to remap the Baranof Fan system. Results show that the fan is larger than previously recognized and constructed by two primary depocenters linked to distinct glacial sediment pathways, with accommodation space controlled by down-warping of the Pacific Plate. Regional seismic mapping combined with age constraints from International Ocean Discovery Program Expedition 341 reveals an ~10% increase in estimated sediment volumes in the eastern gulf and demonstrates that sediment flux following intensification of Northern Hemisphere glaciation (~2.7 Ma) was strongly climate driven, with late Pleistocene volumes highlighting the dominant role of glacial erosion in hemispheric mass balance.

At the Nicaragua segment of the Middle America Trench, we then investigate forearc geomorphology. We analyze high-resolution bathymetry along the Nicaragua segment of the Middle America Trench. Spatial wavelength relationships between incoming plate structures and forearc morphology, pervasive mid-slope normal faulting, and slope failures provide geomorphic evidence for active basal subduction erosion and strong coupling between incoming plate structure and upper-plate deformation.

Degree Name

Earth and Planetary Sciences

Level of Degree

Doctoral

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Lindsay Lowe Worthington

Second Committee Member

Eric Lindsey

Third Committee Member

Marisa Repasch

Fourth Committee Member

Maureen Walton

Language

English

Keywords

deep-sea fans, sediment flux, tectonic geomorphology, Gulf of Alaska, subduction erosion, Middle America Trench

Document Type

Dissertation

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