Linking Hydraulic Properties In Supercritical Submarine Distributary Channels To Depositional-Lobe Geometry

Hamilton, Paul B.; Gaillot, Gwladys; Strom, Kyle; Fedele, J. J.; Hoyal, D. C. J. D.

doi:10.2110/jsr.2017.53

Cited by 36 publications

(56 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A lack of significant channelization could cause flows to traverse completely "out-of-grade" areas (sensu Prather, 2003) that would erode the slope, driving entrainment of mud clasts. Unconfined flows would spread laterally (Al Ja 'Aidi et al, 2004;Kane et al, 2008;Hamilton et al, 2017) and be more susceptible to topographic perturbations than more channelized flows (Kneller and Buckee, 2000). Disconnected upper slope feeder systems would suggest that relative sea-level falls were not of sufficient magnitude or duration to expose the shelf or bring the deltas close to the shelf edge (Fig.…”

Section: Discussion Units A/b B/c and D/ementioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

Section: Discussion Units A/b B/c and D/ementioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Hughes Clarke, ). The presence of these subcritical sediment waves in the downstream parts of CLTZs also challenges the idea that mid‐sized fans, like those in the Karoo, probably exhibit flows close to critical Froude numbers, at and beyond the CLTZ (Hamilton et al ., ), although such conditions are likely in upstream parts of CLTZ where scouring occurs.…”

Section: Discussionmentioning

confidence: 99%

Architecture and morphodynamics of subcritical sediment waves in an ancient channel–lobe transition zone

et al. 2018

View full text Add to dashboard Cite

In modern systems, submarine channel-lobe transition zones show a welldocumented assemblage of depositional and erosional bedforms. In contrast, the stratigraphic record of channel-lobe transition zones is poorly constrained, because preservation potential is low and criteria have not been established to identify depositional bedforms in these settings. Several locations from an exhumed fine-grained base of slope system (Unit B, Laingsburg depocentre, Karoo Basin, South Africa) show exceptional preservation of sandstone beds with distinctive morphologies and internal facies distributions. The regional stratigraphic context, lack of a basal confining surface, wave-like morphology in dip section, size and facies characteristics support an interpretation of subcritical sediment waves within a channel-lobe transition zone setting. Some sediment waves show steep (10 to 25°) unevenly spaced (10 to 100 m) internal truncation surfaces that are dominantly upstream-facing, which suggests significant spatio-temporal fluctuations in flow character. Their architecture indicates that individual sediment wave beds accrete upstream, in which each swell initiates individually. Lateral switching of the flow core is invoked to explain the sporadic upstreamfacing truncation surfaces, and complex facies distributions vertically within each sediment wave. Variations in bedform character are related to the axial to marginal positions within a channel-lobe transition zone. The depositional processes documented do not correspond with known bedform development under supercritical conditions. The proposed process model departs from established mechanisms of sediment wave formation by emphasising the evidence for subcritical rather than supercritical conditions, and highlights the significance of lateral and temporal variability in flow dynamics and resulting depositional architecture.

show abstract

“…The identification of deep-marine hierarchy has enabled stratigraphic heterogeneities to be better characterised and communicated an approach which has benefitted hydrocarbon reservoir modelling, resulting for example in more accurate history matching of fluid flow in channel deposits (Stewart et al, 2008) and in improved connectivity models in lobe deposits (Zhang et al, 2009;Hofstra et al, 2016). These largely descriptive hierarchical schemes have also been used to inform models of deep-marine processes (e.g., Gardner et al, 2003;McHargue et al, 2011;Macauley & Hubbard, 2013;Terlaky et al, 2016;Hamilton et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Hierarchical classifications of the sedimentary architecture of deep-marine depositional systems

Cullis

Colombera

Patacci

et al. 2018

Earth-Science Reviews

View full text Add to dashboard Cite

show abstract

Linking Hydraulic Properties In Supercritical Submarine Distributary Channels To Depositional-Lobe Geometry

Cited by 36 publications

References 52 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

Architecture and morphodynamics of subcritical sediment waves in an ancient channel–lobe transition zone

Hierarchical classifications of the sedimentary architecture of deep-marine depositional systems

Contact Info

Product

Resources

About