September 2012

Effect of the K/Pg boundary Chicxulub impact on the northern Gulf of Mexico

Erik Scott, Marathon Oil Company

Abstract Summary

The Chicxulub bolide impact on the Yucatan peninsula at the Cretaceous-Paleogene (K/Pg) boundary has been postulated as the trigger that re-mobilized sediment into mass transport flows on the submerged shelf along eastern North and Central America as well as around the Gulf of Mexico and redistributed sediment out into the deep water Atlantic, Caribbean and Gulf of Mexico. Well log and biostratigraphic data from Cretaceous well penetrations in the deep-water northern Gulf of Mexico show a distinctive micritic deposit at the K/Pg boundary that is similar in composition and biostratigraphy to sediments found near the Chicxulub Crater, DSDP/ODP cores and outcrops in Cuba. Investigation of seismic data in the northern Gulf of Mexico shows anomalous sedimentary wedges of high amplitude reflectors situated at the top of the Cretaceous section that are interpreted to be the resulting deposit from the mass transport flows and suspension fallout initiated by the impact. At the end of the Cretaceous, the northern Gulf of Mexico was undergoing allocthonous salt movement from the Jurassic Louann Salt that was expressed in numerous salt highs defining potential clastic sediment fairways. The sediment redistribution caused by the Chicxulub impact filled in the available accommodation space around the salt highs, as well as depositing on the highs themselves, and altered the seafloor topography across the northern Gulf of Mexico. This resulted in an efficient transportation pathway from shelf to deep water and influenced the sedimentation patterns of the subsequent sediment gravity flows of the Wilcox Formation.

Biographical Sketch

Erik Scott is a geologist working for Marathon Oil in Houston, Texas on a wide variety of projects in both exploration and production. Over his career, he has engaged in stratigraphic analysis of numerous areas including the Gulf of Mexico, North Sea, offshore West Africa, and the eastern Mediterranean. He received a Ph.D. in geology from Louisiana State University, studying under Dr. Arnold H. Bouma, with whom he investigated influences on deepwater sedimentation, based on the turbidite outcrops in the Karoo Basin of South Africa.