Characteristics of axially-sourced turbidite sedimentation on an active wedge-top basin (Annot Sandstone, SE France)

Salles, Lise; Ford, Mary; Joseph, Philippe

doi:10.1016/j.marpetgeo.2014.01.020

Cited by 23 publications

(58 citation statements)

References 30 publications

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“…High-amplitude seabed topog raphy and associated major gradient changes have been well documented in seismic reflection data sets of modern systems, such as in the Gulf of Mexico (Prather et al, 1998 Fig. 1D), the Western Niger Delta slope (Jobe et al, 2017;Fig 1E), offshore Norway (Jackson et al, 2008) and offshore Angola (Hay, 2012), as well as in outcrop studies, including the Castagnola Formation (4-12°; Felletti, 2002;Southern et al, 2015;Marini et al, 2016); the Laga Formation (6-8°; Marini et al, 2015); and the Grès d'Annot (4-10°; Amy et al, 2007;Salles et al, 2014).…”

Section: Introductionmentioning

confidence: 80%

Disconnected submarine lobes as a record of stepped slope evolution over multiple sea-level cycles

et al. 2018

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The effects of abrupt changes in slope angle and orientation on turbidity current behavior have been investigated in numerous physical and numerical experiments and examined in outcrop, subsurface, and modern systems. However, the long-term impact of subtle and evolving seabed topography on the stratigraphic architecture of deep-water systems requires fine-scale observations and extensive 3-D constraints. This study focuses on the Permian Laingsburg and Fort Brown formations, where multiple large sand-rich systems (Units A-F) have been mapped from entrenched slope valleys, through channel-levee systems, to basin-floor lobe complexes over a 2500 km 2 area. Here, we investigate three thinner (typically <5 m in thickness) and less extensive sand-rich packages, Units A/B, B/C, and D/E, between the large-scale systems. Typically, these sand-rich units are sharp-based and topped, and contain scours and mudstone clast conglomerates that indicate deposition from high-energy turbidity currents. The mapped thickness and facies distribution suggest a lobate form. These distinctive units were deposited in similar spatial positions within the basin-fill and suggest similar accommodation patterns on the slope and basin floor prior to the larger systems (B, C, and E). Stratigraphically, these thin units represent the first sand deposition following major periods of shut-down in sediment supply, and are interpreted as marking a partial re-establishment of sand delivery pathways creating "disconnected lobes" that are fed mainly by flows sourced from failures on the shelf and upper slope rather than major feeder channel-levee systems.Thickness and facies patterns throughout the deep-water stratigraphy suggest seabed topography was present early in the basin formation and maintained persistently in a similar area to ultimately form a stepped slope profile. The stepped slope profile evolved through three key stages of development: Phase 1, where sediment supply exceeds deformation rate (likely caused by differential subsidence); Phase 2, where sediment supply is on average equal to deformation rate; and Phase 3, where deformation rate outpaces sediment supply. This study demonstrates that smaller systems are a sensitive record of evolving seabed topography and they can consequently be used to recreate more accurate paleotopographic profiles.

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Section: Introductionmentioning

confidence: 80%

Disconnected submarine lobes as a record of stepped slope evolution over multiple sea-level cycles

et al. 2018

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“…Turbidites with broad downslope ‘pinch and swell’ geometries and poor lateral continuity have commonly been recognized in outcrop studies (e.g. Salles et al ., ). A similar stripey pattern of deposition along the higher‐resolution fold (on the forelimb in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…) are considered to represent some typical topographic features of a DWFTB, simplified as isolated features to study in detail their individual impact on turbidity current behaviour and sand deposition. The folds in the models have a gentle backlimb inclination of ca 4° to 6° and steeper forelimb inclination of ca 13° to 16°, comparable to the shapes of thrusts with fault‐propagation folds seen on the modern sea floor, in seismic sections and in outcrop‐based restorations (McCaffrey & Kneller, ; Heiniö & Davies, ; Clark & Cartwright, ; Morley, ; Morley et al ., ; Salles et al ., ; Jolly et al ., ), although the steepening forelimb in reality may be due to the formation of scarps (Heiniö & Davies, ; Clark & Cartwright, ). The fold hinges in model 3 (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…; e.g. Shanmugam & Moiola, ; Kneller et al ., ; Hodgson et al ., ; Clayton, ; Haughton, , ; Kneller, ; Kneller & McCaffrey, ; Al‐Ja'Aidi, ; McCaffrey & Kneller, ; Sinclair & Tomasso, ; Lamb et al ., ; Clark & Cartwright, ; Bakke et al ., ; Salles et al ., ; Patacci et al ., ; Kneller et al ., ). Turbidity currents in these settings commonly encounter thrusts with fault‐propagation folds as transverse obstacles when descending sea‐floor slopes folded by contractional tectonics or diapirism, or when overriding the slump topography of mass‐transport complexes.…”

Section: Introductionmentioning

confidence: 99%

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Response of unconfined turbidity current to deep‐water fold and thrust belt topography: Orthogonal incidence on solitary and segmented folds

Howlett

Nemec

et al. 2019

Sedimentology

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Sea‐floor topography of deep‐water folds is widely considered to have a major impact on turbidity currents and their depositional systems, but understanding the flow response to such features was limited mainly to conceptual notions inspired by small‐scale laboratory experiments. High‐resolution three‐dimensional numerical experiments can compensate for the lack of natural‐scale flow observations. The present study combines numerical modelling of thrusts with fault‐propagation folds by Trishear3D software with computational fluid dynamics simulations of a natural‐scale unconfined turbidity current by MassFlow‐3D™ software. The study reveals the hydraulic and depositional responses of a turbidity current (ca 50 m thick) to typical topographic features that it might encounter in an orthogonal incidence on a sea‐floor deep‐water fold and thrust belt. The supercritical current (ca 10 m sec−1) decelerated and thickened due to the hydraulic jump on the fold backlimb counter‐slope, where a reverse overflow formed through current self‐reflection and a reverse underflow was issued by backward squeezing of a dense near‐bed sediment load. The reverse flows were re‐feeding sediment to the parental current, reducing its waning rate and extending its runout. The low‐efficiency current, carrying sand and silt, outran a downslope distance of >17 km with only modest deposition (<0·2 m) beyond the fold. Most of the flow volume diverted sideways along the backlimb to surround the fold and spread further downslope, with some overspill across the fold and another hydraulic jump at the forelimb toe. In the case of a segmented fold, a large part of the flow went downslope through the segment boundary. Preferential deposition (0·2 to 1·8 m) occurred on the fold backlimb and directly upslope, and on the forelimb slope in the case of a smaller fold. The spatial patterns of sand entrapment revealed by the study may serve as guidelines for assessing the influence of substrate folds on turbiditic sedimentation in a basin.

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“…Many of these studies originate from basins with syn-and/or post-depositional compressional tectonics (e.g. Mutti, 1983;Haughton, 1994;Sinclair and Tomasso, 2002;Hodgson and Haughton, 2004;Bernhardt et al, 2011;Salles et al, 2014;Cantalejo and Pickering, 2014), although paleogeographic reconstructions rarely account for post-depositional tectonic shortening. Studies that undertake palinspastic restoration of turbidite systems, which revises the geometry and dimensions of systems to the configuration during deposition, are rare and tend to be in small depocenters (e.g.…”

Section: Introductionmentioning

confidence: 99%

Palinspastic restoration of an exhumed deepwater system: A workflow to improve paleogeographic reconstructions

et al. 2015

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Characteristics of axially-sourced turbidite sedimentation on an active wedge-top basin (Annot Sandstone, SE France)

Cited by 23 publications

References 30 publications

Disconnected submarine lobes as a record of stepped slope evolution over multiple sea-level cycles

Disconnected submarine lobes as a record of stepped slope evolution over multiple sea-level cycles

Response of unconfined turbidity current to deep‐water fold and thrust belt topography: Orthogonal incidence on solitary and segmented folds

Palinspastic restoration of an exhumed deepwater system: A workflow to improve paleogeographic reconstructions

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