Timing of Late Pleistocene Shelf-Margin Deltaic Depositional and Mass-Transport Events, East Breaks 160-161 Shelf-Edge Minibasin, Gulf of Mexico
John M. Armentrout, 2013. "Timing of Late Pleistocene Shelf-Margin Deltaic Depositional and Mass-Transport Events, East Breaks 160-161 Shelf-Edge Minibasin, Gulf of Mexico", Shelf Margin Deltas and Linked Down Slope Petroleum Systems–Global Significance and Future Exploration Potential, Harry H. Roberts, Norman C. Rosen, Richard H. Fillon, John B. Anderson
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Lithologic, biostratigraphic and isotopic data from cuttings provides calibration of three sigmoidal, clinoform packages separated by regionally continuous, parallel seismic facies. This depositional geometry is interpreted as a shelf-margin, deltaic wedge deposited within the East Breaks 160-161 minibasin. A chaotic seismic facies package extending over more than 84 mi2 (218 km2) occurs between two clinothem packages of Ericson Zone Y (71 ka BP to 12 ka BP). The chaotic package is interpreted to be a mass-transport complex that failed during the accelerated rate of sea level fall during late Oxygen Isotope Stage 3 (approximately 30 to 20 Ka). Clinothem foresets, bottom sets and the mass-transport complex are predominantly clay with minor siltstone. Sands are restricted to proximal topsets and fluvial channels.
The mass-transport complex consists of three subfacies: rotated-block, hummocky-mounded, and disrupted. Distribution and volume of these facies suggests that only the rotated-block subfacies has been significantly transported, and that the hummocky-mounded and disrupted subfacies result from different degrees of disruption of ponded, clay-prone layered sediments by compression and dewatering triggered by the submarine slide of rotated blocks.