Abstract

Sequence accumulation rate maps based on graphic correlation of reported stratigraphic events in >200,000 industry wells and published studies provide a detailed view of Paleocene-Eocene deposystems in the Gulf of Mexico Basin that is chronostratigraphically consistent across the entire region. At the end of the Mesozoic, epeiric carbonates, basin margin banks, steep continental slopes, and deepening eastern and western basin floors establish a morphologic framework that begins receiving large volumes of siliciclastic detritus from the developing Laramide uplift. This sediment flood initiates the Paleocene-Eocene depositional cycle. Paleocene-Eocene depositional cycle accumulation patterns reveal accommodation dominated primarily by the K/T calcareous to siliceous basin transition and secondarily by mobile salt.

Primary Paleocene-Eocene depositional cycle architecture consists of expanded shelf margin depocenters, the La Salle, Calvert, and Holly Springs delta systems. Shelf-edge delta lobes associated with these systems supply sediment to robust Texas–Campeche Basin fan systems, the Chincontepec fed from southeastern Mexico, the La Salle and Yoakum Canyon systems fed from South Texas, and the Western Holly Springs system fed from Southeast Texas. Eastern lobes of the Holly Springs delta system in South Louisiana feed a weaker salt related fan system in the north central Gulf via the St. Landry Canyon, the Eastern Holly Springs fan system, and a more distal Chicxulub fan in the deep eastern Gulf. Inclusions of Eocene sediments in salt bodies within the Neogene salt canopy and higher accumulation rate subsalt Paleocene-Eocene section support Paleocene-Eocene depositional cycle salt displacement during deposition of the Eastern Holly Springs fan. Slope aprons play a role in the transfer of sediments from shelf to basin during parts of the Paleocene-Eocene depositional cycle, but for most of the interval sediments are delivered directly to fans, bypassing the lower slope.

The end of the Paleocene-Eocene depositional cycle coincides with stabilization of Rocky Mountain foreland basins and uplift of the Colorado Plateau and the Rio Grande Rift. A sediment-starved western Gulf Basin in the late Eocene limits optimal reservoir development in the Western Gulf to the early Eocene (ca. 55.2-47.7 Ma). Although Paleocene-Eocene depositional cycle fans in the eastern Gulf are thinner they may contain significant quantities of sand. The period of optimal reservoir accumulation in the eastern Gulf may last somewhat longer, extending into the earliest Oligocene (ca. 55.2-32.5 Ma).