Morphology and controls on the evolution of a mixed carbonate–siliciclastic submarine canyon system, Great Barrier Reef margin, north-eastern Australia

Puga‐Bernabéu, Ángel; Webster, Jody M.; Beaman, Robin J.; Guilbaud, Vincent

doi:10.1016/j.margeo.2011.09.013

Cited by 82 publications

(64 citation statements)

References 73 publications

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“…However, the real and simulated deposits differ in several notable ways (Figure 8). Simulated flows extend outward into the axis of the Queensland Trough as the turbidite record suggests (Puga‐Bernabéu et al, 2011; Watts et al, 1993), where upon initiation, stream power is heightened by steep carbonate platform topography and localization of rivers through gaps between platforms. Similar to the flows observed in backscatter imagery, simulated flows are deflected northward by the Queensland Trough, where the lack of development of any significant submarine fans is attributed to relatively low supply and the deepening geometry of the trough.…”

Section: Discussionmentioning

confidence: 98%

The Influence of Carbonate Platforms on the Geomorphological Development of a Mixed Carbonate‐Siliciclastic Margin (Great Barrier Reef, Australia)

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Webster

et al. 2020

Geochem Geophys Geosyst

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Sedimentation regimes on the Great Barrier Reef margin often do not conform to more conventional sequence stratigraphic models, presenting difficulties when attempting to identify key processes that control the margin's geomorphological evolution. By obstructing and modifying down-shelf and down-slope flows, carbonate platforms are thought to play a central role in altering the distribution and morphological presentation of common margin features. Using numerical simulations, we test the role of the carbonate platforms in reproducing several features (i.e., paleochannels, shelf-confined fluvial sediment mounds, shelf-edge deltas, canyons, and surface gravity flows) that have been described from observational data (seismic sections, multibeam bathymetry, sediment cores, and backscatter imagery). When carbonate platforms are present in model simulations, several notable geomorphological features appear, especially during lowstand. Upon exposure of the shelf, platforms reduce stream power, promoting mounding of fluvial sediments around platforms. On the outer shelf, rivers and streams are re-routed and coalesce between platforms, depositing shelf-edge deltas and incising paleochannels through knickpoint retreat. Additionally, steep platform topography triggers incision of slope canyons through turbidity currents, and platforms act as conduits for the localized delivery of land and shelf-derived sediments to the continental slope and basin. When platforms are absent from the topographic surface, the model is unable to reproduce many of these features. Instead, a more typical "reciprocal-type" sedimentation regime arises. Our results demonstrate the essential role of carbonate platform topography in modulating key bedload processes. Therefore, they exert direct control on the development of various geomorphological features within the shelf, slope, and basin environments.Plain Language Summary The modern Great Barrier Reef sits atop the skeletal remains of its ancestors. These remains form large (50-200 km 2 ) columns of chalk (or carbonate platforms) that rest on the northeast Australian continental shelf. By comparing observational data with computer simulations, we find that these platforms majorly disrupt and modify the flow of rivers and deep-sea density currents during periods of lower sea level. When platforms are exposed, they become hills, forming steep topographic high points that are large enough to re-route rivers and promote incision on the continental slope. On the modern seafloor, evidence of this activity is preserved in the form of ancient deltas, paleochannels, submarine canyons, and sediment flows that stretch across the abyssal plain. The morphology and distribution of these seafloor features are more robustly accounted for when carbonate platforms are present, and many of them do not appear in computer simulations where carbonate platforms are absent. Our work shows that carbonate platforms can alter seascapes in ways that are traditionally less understood.

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Section: Discussionmentioning

confidence: 98%

The Influence of Carbonate Platforms on the Geomorphological Development of a Mixed Carbonate‐Siliciclastic Margin (Great Barrier Reef, Australia)

Thran

East

Webster

et al. 2020

Geochem Geophys Geosyst

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“…In addition to these continent-wide studies, Australian submarine canyons have been mapped at local to regional scales along the southwestern (Von Der Borch, 1968;Exon et al, 2005), south-south-eastern (Hill et al, 1998;Gingele et al, 2004;Hill et al, 2005;Mitchell et al, 2007) and north-eastern (Puga-Bernabeu et al, 2011Webster et al, 2012) margins with a focus on canyon geology, geomorphology and sedimentology. Canyon-specific studies of local patterns in benthic biodiversity (e.g.…”

Section: Submarine Canyons In Australiamentioning

confidence: 99%

“…5g) and Gippsland Canyons (including the Bass Canyon system) in the southeast (Fig. 5h) (Hill et al, 1998Gingele et al, 2004;Mitchell et al, 2007) and the canyons that fringe the outer Great Barrier Reef (Puga-Bernabeu et al, 2011Webster et al, 2012;Fig. 5c).…”

Section: Controls On the Distribution And Form Of Submarine Canyonsmentioning

confidence: 99%

Classification of submarine canyons of the Australian continental margin

et al. 2014

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Submarine canyons influence oceanographic processes, sediment transport, productivity and benthic biodiversity from the continental shelf to the slope and beyond. However, not all canyons perform the same function. The relative influence of an individual canyon on these processes will, in part, be determined by its form, shape and position on the continental margin. Here we present an analysis of canyon geomorphic metrics using an updated national dataset of 713 submarine canyons surrounding mainland Australia. These metrics (attributes) for each canyon are used to classify them into canyon types across a hierarchy of physical characteristics separately for shelf-incising (n = 95) and slope-confined (blind; n = 618) canyons. We find that the canyon metrics describe a wide variety of canyon form and complexity that is consistent with a population of canyons that has evolved at different rates around the Australian margin since the break-up of Gondwana. The large number of slopeconfined canyons is interpreted to reflect dominance of slope mass-wasting processes over erosive turbidity flows from fluvial and shelf sources on an arid continent. The distribution of submarine canyons around the Australian margin is not regular, with clusters occurring in the east, southeast, west and southwest where the margin is steepest. The classification result provides a quantitative framework for describing canyon heterogeneity for application in studies of geological controls on individual canyons, canyon oceanography and canyon biodiversity.Crown

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“…This broad statement was based on the inherently steep slopes and the continuous, rigid build‐ups of tropical reef‐rimmed carbonate platforms, which favour a linear sediment supply and subsequent elongate sediment accumulation at the base of slope. However, recent work on two archetypical tropical reef platforms, the Bahamas and the Great Barrier Reef (Puga‐Bernabéu et al ., , ; Mulder et al ., ,b; Betzler et al ., ; Reijmer et al ., ; and references therein), and the growing examples of calciclastic submarine fans in the ancient record (Betzler et al., ; see Payros & Pujalte, , for a review) suggest that the carbonate apron model needs revision.…”

Section: Discussionmentioning

confidence: 98%

“…Although the understanding of carbonate slope systems has substantially improved in recent years, most current research (Lantzsch et al ., ; Verwer et al ., ; Van der Kooij et al ., ; Loucks et al ., ; Puga‐Bernabéu et al ., , ; Mulder et al ., ,b, ; Rankey & Doolittle, ; Santantonio et al ., ; Betzler et al ., ; Minzoni et al ., ; Reijmer et al ., ) has focused on accretionary margins and growth escarpment margins (according to the scheme proposed by Playton et al ., ), whereas carbonate deposition related to inherited escarpment margins remains relatively poorly understood. In addition, most known examples of carbonate accumulation on inherited escarpments are related to extensional fault scarps (Bosence et al ., ; Cross et al ., ; Brachert et al ., ; Drzewiecki & Simó, ; Bosence, ; Cross, ).…”

Section: Introductionmentioning

confidence: 99%

Heterozoan carbonate deposition on a steep basement escarpment (Late Miocene, Almería, south‐east Spain)

et al. 2017

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Heterozoan temperate‐water carbonates mixed with varying amounts of terrigenous grains and muddy matrix (Azagador limestone) accumulated on and at the toe of an inherited escarpment during the late Tortonian–early Messinian (late Miocene) at the western margin of the Almería–Níjar Basin in south‐east Spain. The escarpment was the eastern end of an uplifting antiform created by compressive folding of Triassic rocks of the Betic basement. Channelized coralline‐algal/bryozoan rudstone to coarse‐grained packstone, together with matrix‐supported conglomerate, are the dominant lithofacies in the higher outcrops, comprising the deposits on the slope. These sediments mainly fill small canyon‐shaped, half‐graben depressions formed by normal faults active before, during and after carbonate sedimentation. Roughly bedded and roughly laminated coralline‐algal/bryozoan rudstone to coarse‐grained packstone are the main lithofacies forming an apron of four small (kilometre‐scale) lobes at the toe of the south‐eastern side of the escarpment (Almería area). Channelized and roughly bedded coralline‐algal/bryozoan rudstone to coarse‐grained packstone, conglomerates, packstone and sandy silt accumulated in a small channel‐lobe system at the toe of the north‐eastern side of the escarpment (Las Balsas area). Carbonate particles and terrigenous grains were sourced from shallow‐water settings and displaced downslope by sediment density flows that preferentially followed the canyon‐shaped depressions. Roughly laminated rudstone to packstone formed by grain flows on the initially very steep slope, whereas the rest of the carbonate lithofacies were deposited by high‐density turbidite currents. The steep escarpment and related break‐in‐slope at the toe favoured hydraulic jumps and the subsequent deposition of coarse‐grained, low‐transport efficiency skeletal‐dominated sediment in the apron lobes. Accelerated uplift of the basement caused a relative sea‐level fall resulting in the formation of outer‐ramp carbonates on the apron lobes, which were in turn overlain by lower Messinian coral reefs. The Almería example is the first known ‘base of slope’ apron within temperate‐water carbonate systems.

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Morphology and controls on the evolution of a mixed carbonate–siliciclastic submarine canyon system, Great Barrier Reef margin, north-eastern Australia

Cited by 82 publications

References 73 publications

The Influence of Carbonate Platforms on the Geomorphological Development of a Mixed Carbonate‐Siliciclastic Margin (Great Barrier Reef, Australia)

The Influence of Carbonate Platforms on the Geomorphological Development of a Mixed Carbonate‐Siliciclastic Margin (Great Barrier Reef, Australia)

Classification of submarine canyons of the Australian continental margin

Heterozoan carbonate deposition on a steep basement escarpment (Late Miocene, Almería, south‐east Spain)

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