Regional controls on the formation of ancestral DeSoto Canyon by the Chicxulub impact

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http://www.gcags.org/Journal/GCAGS.Journal.Vol.2.html
Author(s): Denne, Richard A.; Blanchard, Robert H.
Author Affiliation(s): Primary:
Marathon Oil Corporation, Houston, TX, United States
Volume Title: GCAGS Journal
Source: GCAGS Journal, Vol.2, p.17-28. Publisher: Gulf Coast Association of Geological Societies, Austin, TX, United States
Note: In English. 80 refs.; illus., incl. sketch maps, sects.
Summary: The DeSoto Canyon, a subsea canyon in the northeastern Gulf of Mexico, has a history of erosion dating back to the Cretaceous/Paleogene boundary (KPgB). The canyon resides within the DeSoto Canyon Salt Basin (DCSB), a large, basement-controlled graben formed by Jurassic rifting. The basin was the focus of deposition throughout the Late Jurassic and Early Cretaceous, although seismic profiles indicate that sedimentation was nearly uniform by the end of the Jurassic. The area was dominated by carbonate reef production during the Early Cretaceous, transitioning to siliciclastic deposition north of the canyon and pelagic, carbonate mud south of the canyon during the Cenomanian. Initial incision of the canyon is visible on reflection seismic profiles as a series of truncated reflections that outline a canyon-shaped feature on the Upper Cretaceous isochore map. The downcutting surface ties to the KPgB reflection in nearby industry wells. Although much of the early canyon was buried by Cenozoic siliciclastic deposition, it remained a zone of instability, characterized by chaotic seismic facies and common truncation of internal reflections. Smaller than the ancestral canyon, the modern DeSoto Canyon remains within the confines of the initial KPgB incision. It is hypothesized that differential subsidence preferentially induced faulting and fracturing of the carbonate margin in front of the DCSB. Chicxulub impact-induced seismicity caused the fractured margin to collapse at the KPgB, enabling unconsolidated Upper Cretaceous sediments to fail and the ancestral canyon to form. There is no evidence that the Suwannee Current played a significant role in formation of the canyon, although there is a possibility that the channel acted as a funnel for an impact-induced tsunami that removed Upper Cretaceous sediments from within the Suwannee Channel and deposited them on the Blake Plateau to the east.
Year of Publication: 2013
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 20 Geophysics, Applied; Atlantic Ocean; Bathymetry; Biostratigraphy; Canyons; Cenozoic; Chicxulub Crater; Controls; Cretaceous; DSDP Site 540; De Soto Canyon; Deep Sea Drilling Project; Erosion; Failures; Florida Escarpment; Geophysical methods; Geophysical profiles; Geophysical surveys; Gulf of Mexico; IPOD; Impacts; Isochores; Jurassic; K-T boundary; Leg 77; Lower Paleocene; Marine sedimentation; Mesozoic; North Atlantic; Paleocene; Paleogene; Reefs; Reflection; Rift zones; Sedimentation; Seismic methods; Seismic profiles; Seismicity; Stratigraphic boundary; Stratigraphy; Surveys; Suwannee Channel; Tertiary; Upper Cretaceous; Upper Jurassic
Coordinates: N280000 N300000 W0860000 W0900000
N234943 N234944 W0842214 W0842216
Record ID: 2014016477
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