Structure, Stratigraphy and Hydrocarbon Potential of the Colombian Caribbean Margin and Tsunamigenic Hazards in the Western Caribbean and the South China Sea

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The Colombian Caribbean Margin extends for ~850 km, southwest to northeast, from the Panama to Venezuela. Along the margin, the subduction of the Caribbean plate has formed an accretionary prism defining the edge of the overriding South American plate. This dissertation focusses on the late Mesozoic to recent, tectonic, structural, and stratigraphic history of the deepwater portion of the region, with an emphasis on hydrocarbon exploration potential. I also characterize the submarine landslide related tsunami hazard of the western Caribbean region and for the South China Sea. In Chapter 2, I identify and map three giant (>1000’s km3), Plio-Pleistocene submarine landslides along the Colombian subduction margin. To understand the tsunamigenic hazards of a recurrence of such an event, I model a potential tsunami source derived from the over-steepened upper slopes of the present-day Magdalena Fan. The modeling indicates an analogous slope failure would result in a significant tsunami, impacting population centers throughout the western Caribbean. In Chapter 3, I apply the same methods as Chapter 2 to document the history of slope failures in the northern South China Sea. Numerical modeling provides constraints on the tsunamigenic potential of an incipient slope failure and the geohazard potential of large-scale mass wasting along this margin. In Chapter 4, I map a 450 km long segment of the South Caribbean Deformed Belt offshore the Guajira Peninsula. The mapping reveals the subducting Caribbean Plate dipping beneath the northwestern margin of South America, the internal character of The South Caribbean Deformed Belt, and prominent shale diapirs associated with leading thrust faults. Fringing the deformation front is a well-developed proto-thrust zone, where the flat-lying sediments atop the subducting Caribbean Plate are undergoing the first stages of subduction-related deformation. In Chapter 5, I build upon the results from Chapters 2 and 4 to interpret the structure and stratigraphy of the Colombian Basin. I delineate the main elements of a deepwater petroleum system that includes stratigraphic traps within the distal Miocene Magdalena fan section. 1D burial history models and 3D basin modeling indicate that the primary risk for the exploration potential of the area is the presence of a laterally extensive Upper Cretaceous source rock within this depocenter.

Colombia, Mass-Transport, Basin Modeling, Tsunami modeling
Portions of this document appear in: Leslie, S. C., Mann, P., 2016. Giant submarine landslides on the Colombian margin and tsunami risk in the Caribbean Sea. Earth and Planetary Science Letters, 449, 382-394; and in: Sun, Q., Leslie, S. C., 2020. Tsunamigenic potential of an incipient submarine slope failure in the northern South China Sea. Marine and Petroleum Geology, 112, 1-14.