The K/Pg boundary Chicxulub impact deposit in the deep-water Gulf of Mexico; implications for regional stratigraphy and the "MCU"

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Author(s): Denne, Richard A.; Scott, Erik D.; Buddin, Timothy S.; Carlson, Steve D.; Eickhoff, David P.; Hill, Ronald; Spaw, Joan M.
Author Affiliation(s): Primary:
Marathon Oil Company, Houston, TX, United States
Volume Title: 2011 AAPG annual convention & exhibition; abstracts volume
Source: Abstracts: Annual Meeting - American Association of Petroleum Geologists, Vol.2011; AAPG 2011 annual convention & exhibition, Houston, TX, April 10-13, 2011. Publisher: American Association of Petroleum Geologists and Society for Sedimentary Geology, Tulsa, OK, United States
Note: In English
Summary: Although numerous academic studies have examined outcrops and Deep Sea Drilling Program (DSDP) / Ocean Drilling Program (ODP) cores to determine the effects of the Cretaceous / Paleogene (K/Pg) boundary Chicxulub Impact located on the Yucatan Peninsula both globally and along the margins of the Gulf of Mexico, the energy industry has not fully recognized the considerable impact this event had on the deep-water Gulf of Mexico, with the exception of the world-class Cantarell field which was partially created by the Chicxulub Impact. Initial penetrations of the K/Pg boundary in the deep-water were drilled by DSDP Legs 10 and 77 in the southeastern Gulf of Mexico in the 1970's. The term Middle Cretaceous Unconformity (MCU) was coined for what was then believed to be an unconformity identified in the cores between the Upper and Lower Cretaceous layers. The "MCU" (or 'Middle Cretaceous Sequence Boundary') is a high-amplitude seismic reflector that has been mapped in many studies of the Gulf of Mexico basin. Examination of seismic and released log and biostratigraphic data from 16 Cretaceous penetrations by industry in the deep-water Gulf of Mexico identified a distinctive micritic deposit at the K/Pg boundary ranging from 10 to 200 m (30-600') in thickness that is similar in composition to sediments found within the Chicxulub Crater. This relatively homogenous deposit contains a mixture of Cretaceous (Maastrichtian to Aptian) microfossils and unconformably sits on sediments ranging in age from Campanian to Aptian (or older). These findings suggest that the tsunami-wave and seismic shock generated by the Chicxulub Impact removed most, and at some localities, all of the non-indurated Upper to Lower Cretaceous sediments in the deep-water Gulf of Mexico and nearly instantaneously re-deposited them in basinal lows. This implies that the much thinner boundary deposits found at the basin margins are also a product of the impact, and not the result of a purported low-stand at the boundary as theorized by some authors. Our results are in agreement with recent studies that have indicated that the 'MCU' is not an unconformity within the middle Cretaceous, but is an erosional event at the K/Pg boundary produced by the Chicxulub Impact.
Year of Publication: 2011
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 29 Economic Geology, Energy Sources; Atlantic Ocean; Cantarell Field; Cenozoic; Chicxulub Crater; Cretaceous; Deep Sea Drilling Project; Gulf of Mexico; IPOD; K-T boundary; Leg 10; Leg 77; Lower Paleocene; Mesozoic; North Atlantic; Oil and gas fields; Paleocene; Paleogene; Stratigraphic boundary; Stratigraphic traps; Tertiary; Traps; Upper Cretaceous
Coordinates: N200000 N260000 W0840000 W0960000
Record ID: 2015089566
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States