Seismic geomorphology, lithology, and evolution of the late Pleistocene Mars-Ursa turbidite region, Mississippi Canyon area, northern Gulf of Mexico

Sawyer, Derek E.; Flemings, Peter B.; Shipp, R. Craig; Winker, Charles D.

doi:10.1306/08290605190

Cited by 95 publications

(121 citation statements)

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“…Of the two areas investigated by drilling, Ursa Basin (see, e.g., Winker and Booth, 2000;Winker and Shipp, 2002; or the "Expedition 308 summary" chapter for a detailed description of the geological setting) is the location where severe overpressure was identified (see the "Expedition 308 summary" chapter; Flemings et al, 2008) as a consequence of fine-grained muds being sedimented at very high rates, especially in the uppermost Pleistocene. In this setting, repeated slope failure occurred, with manifestations of mass transport deposits (MTDs) being most frequent where the measured overpressures are highest (see the "Expedition 308 summary" chapter; Sawyer et al, 2007;Flemings et al, 2008). This is clearly seen in Figure F1, which shows the combined lithologic, porosity, shear strength, and pore pressure logs for IODP Sites U1322 and U1324.…”

Section: Introductionmentioning

confidence: 91%

Data report: preliminary assessment of Pleistocene sediment strength in the Ursa Basin (Gulf of Mexico continental slope) from triaxial and ring shear test data

Meissl¹,

Behrmann²,

Behrmann³

2010

Proceedings of the IODP

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We report the preliminary results of a triaxial and ring shear study on clay-rich, fine-grained Pleistocene sediments cored in Ursa Basin, Gulf of Mexico continental slope. Specimens from Integrated Ocean Drilling Program (IODP) Expedition 308 Sites U1322 and U1324 document friction coefficients in the range of 0.13-0.31, with internal angles of friction of ~7.4°-17.2° in ring shear experiments. At intermediate (7.624 MPa) to high (15.237 MPa) overburden pressure, the majority of the samples tested show velocity weakening, whereas lower overburden pressures do not give a clear trend regarding velocity weakening or strengthening of the samples. In consolidated-undrained triaxial tests, peak shear stresses observed are between 27 and 140 kPa, with the strongest sample by far coming from a core catcher section. We suspect that this is an effect of fabric changes induced during hydraulic piston coring. One sample coming from the base of a mass transport deposit at Site U1322 is the weakest one tested. Young's moduli calculated range from 2 to 17.4 kPa. Stress paths indicate slight overconsolidation of the samples, which is in line with the information gained from preconsolidation stresses in other studies. Permeability determined from consolidation data is in the range of 10

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Section: Introductionmentioning

confidence: 91%

Data report: preliminary assessment of Pleistocene sediment strength in the Ursa Basin (Gulf of Mexico continental slope) from triaxial and ring shear test data

Meissl¹,

Behrmann²,

Behrmann³

2010

Proceedings of the IODP

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“…The Cretaceous canyon system was flanked by large bounding faults that parallel The faulting is interpreted to reflect "rotated channel-margin sliding" sensu Sawyer et al (2007) and are similar to some outcrop examples of erosion-dominated channels (Williams et al, 1965;Cronin et al, 2007). These faults are the result of …”

Section: Canyon-margin Faultingmentioning

confidence: 96%

Two fundamentally different types of submarine canyons along the continental margin of Equatorial Guinea

Jobe

Lowe

Uchytil

2011

Marine and Petroleum Geology

163

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Most submarine canyons are erosive conduits cut deeply into the world's continental shelves through which sediment is transported from areas of high coastal sediment supply onto large submarine fans. However, many submarine canyons in areas of low sediment supply do not have associated submarine fans and show significantly different morphologies and depositional processes from those of 'classic' canyons. Using three-dimensional seismic reflection and core data, this study contrasts these two types of submarine canyons and proposes a bipartite classification scheme.The continental margin of Equatorial Guinea, West Africa during the late Cretaceous was dominated by a classic, erosional, sand-rich, submarine canyon system. This system was abandoned during the Paleogene, but the relict topography was reactivated in the Miocene during tectonic uplift. A subsequent decrease in sediment supply resulted in a drastic transformation in canyon morphology and activity, initiating the 'Benito' canyon system. This non-typical canyon system is aggradational rather than erosional, does not indent the shelf edge and has no downslope sediment apron. Smooth, draping seismic reflections indicate that hemipelagic deposition is the chief depositional process aggrading the canyons. Intra-canyon lateral accretion 2 deposits indicate that canyon concavity is maintained by thick (> 150 m), dilute, turbidity currents. There is little evidence for erosion, mass wasting, or sand-rich deposition in the Benito canyon system. When a canyon loses flow access, usually due to piracy, it is abandoned and eventually filled. During canyon abandonment, fluid escape causes the successive formation of 'cross-canyon ridges' and pockmark trains along buried canyon axes.Based on comparison of canyons in the study area, we recognize two main types of submarine canyons: 'Type I' canyons indent the shelf edge and are linked to areas of high coarse-grained sediment supply, generating erosive canyon morphologies, sandrich fill, and large downslope submarine fans/aprons. 'Type II' canyons do not indent the shelf edge and exhibit smooth, aggradational morphologies, mud-rich fill, and a lack of downslope fans/aprons. Type I canyons are dominated by erosive, sandy turbidity currents and mass wasting, whereas hemipelagic deposition and dilute, sluggish turbidity currents are the main depositional processes sculpting Type II canyons. This morphology-based classification scheme can be used to help predict depositional processes, grain size distributions, and petroleum prospectivity of any submarine canyon.

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“…5), and were likely initiated during undercutting of the channel-margin substrate. These features are "rotated channel-margin slides" (Sawyer et al, 2007;Jobe et al, 2011) and show progressive rotation on a listric fault surface with up to 150 m of offset (see marker horizon in Fig. 5) that indicate synsedimentary deformation.…”

Section: Evolution Of the Y Channel Systemmentioning

confidence: 99%

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Jobe¹,

Sylvester²,

Parker³

et al. 2015

Journal of Sedimentary Research

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Changes in sediment supply and caliber during the last ~130 ka have resulted in a complex architectural evolution of the Y channel system on the western Niger Delta slope. This evolution consists of four phases, each with documented or inferred changes in sediment supply. Phase 1 flows created wide (1,000 m), low-sinuosity (1.1) channel forms with lateral migration and little to no aggradation. During Phase 2, the Y channel system began to aggrade, creating more narrow (300 m) and sinuous (1.4) channel forms with many meander cutoffs. This system was abandoned at ~ 130 ka, perhaps related to rapid relative sea-level rise during MIS (Marine Isotope Stage) 5. Phase 3 flows were mud-rich and deposited sediment on the outer bends of the channel form, resulting in the narrowing (to 250 m), straightening (to a sinuosity of 1.22), and aggradation of the Y channel system. Renewed influx of sand into the Y channel system occurred with Phase 4 at ~ 50 ka, during MIS 3 sea-level fall. The onset of Phase 4 is marked by the initiation of the Y′ tributary channel, which re-established sand deposition in the Y channel system. Flows entering the Y channel from the Y′ channel were underfit, resulting in inner levee deposition that is most prevalent on outer banks, acting to further straighten (1.21) and narrow (to 200 m wide) the Y channel. The inner levees accumulated quickly as the flows sought equilibrium, with deposition rates > 200 cm/ky. Marked by the presence of the last sand bed, abandonment occurred at ~19 ka in the Y channel and ~15 ka in the Y′ channel and is likely related to progressive abandonment due to shelf-edge delta avulsion and/or progressive sea level rise associated with Melt Water Pulse 1-A. The muddy, 5-meter-thick Holocene layer has thickness variations that mimic those seen in the sandy part of Phase 4, suggesting that dilute, muddy flows continue to affect the modern Y channel system. This unique dataset allows us to unequivocally link changes in submarine channel architecture to variations in sediment supply and caliber. Changes in the updip sediment routing system (i.e. the channel "plumbing") are shown to have profound implications for submarine channel architecture and reservoir connectivity.

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Seismic geomorphology, lithology, and evolution of the late Pleistocene Mars-Ursa turbidite region, Mississippi Canyon area, northern Gulf of Mexico

Abstract: I grant The Pennsylvania State University the non-exclusive right to use this work for the University's own purposes and to make single copies of the work available to the public on a not-for-profit basis if copies are not otherwise available.

Cited by 95 publications

References 35 publications

Data report: preliminary assessment of Pleistocene sediment strength in the Ursa Basin (Gulf of Mexico continental slope) from triaxial and ring shear test data

Data report: preliminary assessment of Pleistocene sediment strength in the Ursa Basin (Gulf of Mexico continental slope) from triaxial and ring shear test data

Two fundamentally different types of submarine canyons along the continental margin of Equatorial Guinea

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

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