Multi-Disciplinary Analyses of Outcropping Late Cretaceous Clinoform Stratigraphy, Magallanes Basin, Chile

Shelf margins are critical transfer zones where sediment, organic matter, and associated fluids move from continents to deep-marine basins. Clinoforms, shelf-edge deltas, submarine canyons, and deep-water channels are central components of these systems, yet their stratigraphic architecture, sediment-routing behaviour, fluid trapping potential, and influence on organic matter preservation are commonly studied separately. The consequence is a limited understanding of how shelf-margin systems evolve as linked depositional networks through time. This thesis investigates Upper Cretaceous strata at Cerro Cazador in the Magallanes Basin, Chile, where a seismic-scale outcrop exposes shelf-edge clinoforms, deltaic strata, an incised submarine canyon, stratigraphic pinch-outs, and down-dip deep-water deposits within a regionally constrained stratigraphic framework. Here, I integrate drone-derived digital outcrop models, field-based structural and sedimentological observations, measured sections, facies analysis, stratigraphic mapping, and organic geochemical and petrographic datasets to reconstruct the evolution of this shelf-margin system from deltaic topsets to distal submarine channels. The results demonstrate a dynamically linked sediment- and organic matter-routing system that represents a world-class analogue to petroliferous clinoform systems present in sedimentary basins around the globe. The foundation of the thesis is a geometrically corrected digital outcrop interpretation generated with a new data projection method (Chapter 1). The cross-section product was used to: (1) document shelf-margin evolution, including the development of a long-lived submarine canyon that recorded a prolonged period of slope readjustment; (2) characterize eight distinct stratigraphic pinch-out styles that capture a range of small-scale flow baffles to large-scale stratigraphic trap analogues; and (3) demonstrate systematic facies- and architecture-linked variability in organic matter across the depositional system. Collectively, this thesis demonstrates that shelf-margin architecture governs sediment routing, stratigraphic trapping, and organic carbon distribution. These results provide a process-based framework for predicting reservoir, seal, and organic matter preservation patterns in ancient and subsurface shelf-margin systems.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Geoscience

Grantor dc:publisher.institution

Science

Year dc:date.issued

2026

Author dc:creator

• Peploe, Thomas George Edward

Advisors dc:contributor.advisor

• Hubbard, Stephen Michial
• Leckie, Dale
• Poyatos-More, Miquel

Committee members dc:contributor.committeemember

• Ezekiel, Justin Chima
• Bourget, Julien

• Sedimentology
• Organic Geochemistry
• Stratigraphy
• Deltas
• Dorotea Formation
• Digital Outcrop Models

Statement dc:rights

• University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.

Language dc:language.iso

en_US

DOI

https://dx.doi.org/10.11575/PRISM/51365

OAI identifier oai:identifier

oai:ucalgary.scholaris.ca:1880/124734