The stratigraphic expression of decreasing confinement along a deep-water sediment routing system: Outcrop example from southern Chile

Pemberton, Erin A. L.; Hubbard, Stephen M.; Fildani, Andrea; Romans, Brian W.; Stright, Lisa

doi:10.1130/ges01233.1

Cited by 51 publications

(61 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data underscore the short-term transience of seafloor geomorphology and multi-phase bed reworking, local deposition, and bypass of sediment-gravity flows active during channel initiation, maintenance, and filling (e.g., Covault et al, 2014). Furthermore, insights from monitoring have inspired reinterpretation of outcropping sedimentary rocks (e.g., Fildani et al, 2013;Hubbard et al, 2014;Bain and Hubbard, 2016;Pemberton et al, 2016). Missing from the short-term record of monitoring is a longer-term perspective, which is afforded by outcropping and subsurface stratigraphic successions (e.g., Deptuck et al, 2003;Hubbard et al, 2014).…”

Section: Introductionmentioning

confidence: 84%

The Stratigraphic Record of Submarine-Channel Evolution

Covault¹,

Sylvester²,

Hubbard³

et al. 2016

TSR

Self Cite

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 84%

The Stratigraphic Record of Submarine-Channel Evolution

Covault¹,

Sylvester²,

Hubbard³

et al. 2016

TSR

Self Cite

View full text Add to dashboard Cite

“…7 and 8), with mean paleoflow toward the northeast. Lenticular erosive features in the Baviaans area may represent either: shallow scours, often associated with channel-lobe transition zones (e.g., Wynn et al, 2002;Macdonald et al, 2011aMacdonald et al, , 2011bHofstra et al, 2015;Pemberton et al, 2016;Brooks et al, 2018b) formed by hydraulic jumps where flows transition from super-to subcritical due to a reduction in slope gradient and/or flow confinement (Mutti andNormark, 1987, 1991;Weirich, 1989;Kostic and Parker, 2006;Sumner et al, 2013;Dorrell et al, 2016); or weakly confined distributive channels eroding into proximal lobes, with distributive patterns likely due to the reduction of slope gradient (e.g., van der Werff and . These characteristics indicate deposition in a base-of-slope area.…”

Section: Discussionmentioning

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

“…In summary, the stratigraphic trend documented through the middle and upper portions of the GF succession, starting from the deposition of CS2, records a progressive increase of the slope gradient that resulted in incremental increases in confinement of turbidity currents through time, as indicated by the stratigraphic transition from high aspect‐ratio to low aspect‐ratio channels (Prather, ; Pemberton et al ., ). The increase of the slope‐gradient is also marked by a progressive variation in the nature of the out of channel, heterolithic deposits upward in the stratigraphy, from sand‐prone (F.A.2) to mud‐prone (F.A.3).…”

Section: Discussionmentioning

confidence: 99%

“…The axis to margin facies transition and the poorly-erosional nature of the basal surfaces at the margins suggest relatively high energy levels in channel axes and progressively lower energy levels towards marginal areas (Navarro et al, 2007;Pemberton et al, 2016). Flows traversing weakly-confined channels are interpreted to have been larger than the axial confinement.…”

Section: Elementary Channel Architecturesmentioning

confidence: 99%

Multi‐scale analysis of a migrating submarine channel system in a tectonically‐confined basin: The Miocene Gorgoglione Flysch Formation, southern Italy

et al. 2018

View full text Add to dashboard Cite

The Miocene Gorgoglione Flysch Formation records the stratigraphic product of protracted sediment transfer and deposition through a long‐lived submarine channel system developed in a narrow and elongate thrust‐top basin of the Southern Apennines (Italy). Channel‐fill deposits are exposed in an outcrop belt approximately 500 m thick and 15 km long, oriented oblique to the palaeoflow, which was roughly south‐eastward. These exceptional exposures of channel‐fill strata allow the stacking architectures and the evolution of the channel system to be analyzed at multiple scales, enabling the effects of syn‐sedimentary thrust tectonics and basin confinement on the depositional system development to be deciphered. Two end‐member types of elementary channel architecture have been identified: high‐aspect‐ratio, weakly‐confined channels, and low‐aspect‐ratio, incisional channels. Their systematic stacking results in a complex pattern of seismic‐scale depositional architectures that determines the stratigraphic framework of the deep‐water system. From the base of the succession, two prominent channel complex sets have been recognized, namely CS1 and CS2, consisting of amalgamated incisional channel elements and weakly‐confined channel elements. These channelized units are overlain by isolated incisional channels, erosional into mud‐prone slope deposits. The juxtaposition of different channel architectures is interpreted to have been governed by regional thrust‐tectonics, in combination with a high subsidence rate that promoted significant aggradation. In this scenario, the alternating ‘in sequence’ and ‘out of sequence’ tectonic pulses of the basin‐bounding thrusts controlled the activation of coarse‐clastic inputs in the basin and the resulting stacking architectures of channelized units. The tectonically‐driven confinement of the depositional system limited the lateral offset in channel stacking, preventing large‐scale avulsions. This study represents an excellent opportunity to analyze the stratigraphic evolution of a submarine channel system in tectonically‐active settings from an outcrop perspective. It should find wide applicability in analogous depositional systems, whose stratigraphic architecture has been influenced by tectonically‐controlled lateral confinement and associated lateral tilting.

show abstract

The stratigraphic expression of decreasing confinement along a deep-water sediment routing system: Outcrop example from southern Chile

Cited by 51 publications

References 88 publications

The Stratigraphic Record of Submarine-Channel Evolution

The Stratigraphic Record of Submarine-Channel Evolution

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

Multi‐scale analysis of a migrating submarine channel system in a tectonically‐confined basin: The Miocene Gorgoglione Flysch Formation, southern Italy

Contact Info

Product

Resources

About