2025 GCAGS Journal, Vol. 14
TITLE
Geomorphic Evolution of the Paleogene Yoakum Canyon in the Northern Gulf of Mexico: Relationship with Coeval Wilcox Deltas and Implications for Basin Floor Fans
AUTHOR(S)
Mariana I. Olariu and Cornel Olariu
ABSTRACT
The Yoakum Canyon of the Gulf Coast Paleocene section is a shelf- and slope-incising canyon that was active during late Lower Wilcox and Middle Wilcox time. It is situated between two large sedimentary depocenters, the Colorado Delta to the east and the Guadalupe Delta to the west. The present-day subsurface expression of the canyon shows a V–shaped cross-sectional profile with a width of about 16 km, shelf indentation exceeding 100 km, and incision of the shelf to a depth of 1 km. High sediment supply during the late Paleocene promoted significant progradation of the earliest Lower Wilcox A deltas. Sustained progradation advanced the Lower Wilcox B deltas to the shelf edge. The delivery system remained docked near the shelf break, and wave-dominated deltas developed in growth faulted compartments during this time. Shelf edge loading resulted in slumping and sediment failure, followed by headward erosion and development of the canyon. During the late Lower Wilcox, the shelf was flooded, and C deltas in Colorado and Guadalupe depocenters built on the inner and middle shelf. Extensive shore-zone systems and a predominantly muddy shelf and upper slope were developed during Middle Wilcox time. The canyon excavation did not significantly contribute to the growth of submarine fans; however, the canyon acted as a conduit for sediment bypass during the late Lower Wilcox and Middle Wilcox times, when shelf depocenters were relatively small. The volume of sediments (330 km3) in the Yoakum Canyon represents about 1% of the volume of AlKeWa fan in the deepwater Gulf. It is inferred that the remaining 99% was transferred via longshore drift from adjacent Colorado deltas into the head of the canyon. The bulk of the canyon fill consists of muddy sediments with isolated sandstone bodies, as indicated by wireline-log patterns. Towards the end of the Middle Wilcox, the canyon was infilled by deltaic and shoreface sandstone bodies.
PAGE(S)
76-86
DOI
https://doi.org/10.62371/TXQB8591
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