Southern Gulf of Mexico Paleocene Through Miocene Paleogeography: Investigating Siliciclastic Sedimentation in Mexico Deepwater

Abstract

Sediment influx from the North American craton shed into the northern Gulf of Mexico basin, creating extensive Paleocene through Miocene deep-water fans which are prolific hydrocarbon reservoirs in US deep-water. Sediment sourcing for northern Gulf of Mexico reservoirs can be linked to drainage catchments developed in the US Laramide tectonic belt; however, less is known about the influence of the southern Laramide sources upon Mexican deep-water sedimentation. Some researchers contend that during the early Cenozoic a foreland system adjacent to the Eastern Sierra Madres had sufficient accommodation space to trap sediments eroded from the nearby Laramide uplands. Moreover, basement-cored Cretaceous carbonate buildups might have created a barrier for potential sediment bypass. This study uses core data, well logs, 2D regional seismic lines, Pemex geologic reports and data from recent literature to synthesize the paleogeographic evolution of the eastern Mexican margin and deepwater systems from Paleocene through Miocene time. Resulting onshore paleogeographic maps define potential entry points for sediment bypass into the Gulf of Mexico. Inferred paleo drainage systems are used to predict deep-water fans. Predictions were based on empirical relationships between length of drainage system and length of deep-water fans. Analysis of onshore paleogeographic trends are then tied to a regional interpretation of 2D seismic lines in the Southern Gulf of Mexico. Paleocene through Miocene structure maps, isochore maps, seismic facies maps, and deep-water paleographic maps highlight areas of interest for oil and gas exploration in the Southern Gulf of Mexico. Results suggest significant deposition of siliciclastic sediments into deepwater southern Gulf of Mexico. Onshore seismic data shows that Paleogene sediments onlap onto Cretaceous carbonate platforms. Nonetheless, data shows at least two Paleogene erosional canyons acting as entry points for sediment bypass into the Gulf of Mexico. Results from drainage systems scaling relationships predict shorter Paleogene deepwater fans than the US counterparts. Accommodation space in the foreland basin is completely filled by Late Oligocene. Offshore Miocene isochore maps show significant thickening towards the eastern Mexican margin. The results of this study improve the current understating of Cenozoic sedimentation in Mexico deepwater.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016