Controls on and Expressions of Submarine Fan Genesis Within a High Accommodation Margin Setting, Santos Basin, Brazil—A High-Resolution Seismic-Stratigraphic and -Geomorphic Case Study

Hadler-Jacobsen, F.; Groth, Audun; Hearn, Rachael Elizabeth; Liestøl, Frode Møller

doi:10.5724/gcs.10.30.0572

Cited by 6 publications

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“…We restore two of the most representative and best‐oriented profiles (i.e., parallel to both the rift‐ and salt‐related tectonic transport direction) imaging the Merluza Graben. Post‐salt horizons are unfolded to a gently dipping, clinoform‐like seabed geometry, characteristic of the prograding clastic slopes identified in this part of the basin (cf., Hadler‐Jacobsen et al., 2010; Modica & Brush, 2004). This workflow thus incorporates more realistic geometries than previous studies by reconstructing the paleo‐seabed through time using the present seabed as a template, and local erosional unconformities and toplaps as additional constraints (cf., Garcia et al., 2012; Pichel & Jackson, 2020b).…”

Section: Data Set and Methodsmentioning

confidence: 99%

The Merluza Graben: How a Failed Spreading Center Influenced Margin Structure, and Salt Deposition and Tectonics in the Santos Basin, Brazil

et al. 2021

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In many of these basins, the timing of salt deposition varies laterally from syn-rift (i.e., during the bulk of crustal extension) to post-rift (i.e., after the bulk of crustal extension ceased); this diachroneity can occur as the timing of rifting and break-up varies along-strike as continents "unzip" (cf., Northern and Southern Red Sea, Augustin et al., 2014;Rowan, 2014), or as the locus of rift-related extension shifts basinward toward the embryonic spreading center. In the latter case, salt deposited in proximal areas after crustal faulting had ceased would be called "post-rift", whereas age-equivalent salt deposited in more distal areas during ongoing crustal faulting and extension would be defined as syn-rift (e.g., the South and Central Atlantic salt basins; Rowan, 2014Rowan, , 2020Tari et al., 2017).Because of the diachroneity in tectonics and deposition, it can be difficult to determine the relative timing of salt deposition, rift-related fault activity, and seafloor spreading (

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Section: Data Set and Methodsmentioning

confidence: 99%

The Merluza Graben: How a Failed Spreading Center Influenced Margin Structure, and Salt Deposition and Tectonics in the Santos Basin, Brazil

et al. 2021

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“…Shoreface sets documented in the present study show a clear resemblance both to modern beach ridges and to ancient beach ridge deposits documented in previous studies (Dreyer et al ., ; Hadler‐Jacobsen et al ., ; Jackson et al ., ; McCullagh & Hart, ; Bourget et al ., ). However, different explanations for the origin of the seismically imaged shoreface sets and beach ridge sets are proposed in different studies.…”

Section: Discussionmentioning

confidence: 99%

“…(), McCullagh & Hart () and Hadler‐Jacobsen et al . (). In contrast, there are numerous studies of geomorphology from modern shoreface systems (e.g.…”

Section: Introductionmentioning

confidence: 99%

Progradational and backstepping shoreface deposits in the Ladinian to Early Norian Snadd Formation of the Barents Sea

et al. 2016

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Shoreface sandstone deposits within the Early Carnian part of the Snadd Formation of the Norwegian Barents Sea can be traced for hundreds of kilometres in the depositional strike direction and for tens of kilometres in the depositional-dip direction. This study uses three-dimensional seismic attribute mapping and two-dimensional regional seismic profiles to visualize the seismic facies of these shoreface deposits and to map their internal stratigraphic architecture at a regional scale. The shoreface deposits are generally elongate but show variable width from north-east to south-west, which corresponds to a sediment source in the northern part of the basin and a southward decrease in longshore sediment transport. The Snadd Formation presents an example of how large-scale progradational shoreface deposits develop. The linear nature of its shoreface deposits contrasts with more irregular, cuspate wave-dominated deltaic shorelines that contain river outlets, and instead implies longshore drift as the main sediment source. In map view, discrete sets of linear features bounded by truncation surfaces scale directly to beach ridge sets in modern counterparts. The shoreface deposits studied here are characteristic in terms of scale and basin-wide continuity, and offer insight into the contrast between shallow marine deposition under stable Triassic Greenhouse and fluctuating Holocene Icehouse climates. Findings presented herein are also important for hydrocarbon exploration in the Barents Sea, because they describe a hitherto poorly understood reservoir play in the Triassic interval, wherein the most prominent reservoir plays have so far been considered to be found in channelized deposits in net-progradational delta-plain strata that form the topsets to shelf-edge clinoforms. The documented presence of widespread wave-dominated shoreface deposits also has implications for how the relative importance of different sedimentary processes is considered within the basin during this period.

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“…Post-salt horizons are unfolded to a gently-dipping, clinoform-like seabed geometry, characteristic of the prograding clastic slopes identified in this part of the basin (cf. Modica and Brush, 2004;Hadler-Jacobsen et al 2010). This workflow thus incorporates more realistic geometries than previous studies by reconstructing the paleo-seabed through time using the present seabed as a template, and local erosional unconformities and toplaps as additional constraints (cf.…”

Section: Restorationsmentioning

confidence: 99%

“…This allows us to quantify and remove the effects of differential loading and basin subsidence, and to provide more accurate estimates of the base-salt geometry, associated salt thickness, and post-salt deformation through time (Pichel and Jackson 2020b). The decompaction is performed using the Sclater and Christie (1980) function and assumes a carbonate (Albian) and siliciclastic (post-Albian) overburden, in agreement with data presented from elsewhere in the basin (Guerra and Underhill, 2012;Hadler-Jacobsen et al, 2010). For the flexural isostasy we use a crustal density of 2.78 g/cm 3 and lithospheric elastic thickness (Te) of 5 km.…”

Section: Restorationsmentioning

confidence: 99%

The Merluza Graben: how a failed spreading centre influenced margin structure, salt deposition and tectonics in the Santos Basin, Brazil

Pichel¹,

Jackson²,

Peel³

et al. 2021

Preprint

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The relative timing between crustal extension and salt deposition can vary spatially along passive margin salt basins as continents unzip or the locus of extension shifts through time towards the embryonic spreading centre. Determining the relative timing of salt deposition, rifting and seafloor spreading is often problematic due to the diachronous nature of rifting, the ability of salt fill pre-existing topography and to the post-rift gravity-driven salt tectonics. We use 2D PSDM seismic data and structural restorations to investigate the Merluza Graben, a large rift-related depocentre located at the proximal and southernmost portion of the Santos Basin, Brazil and at the continuation of a failed spreading centre, the Abimael Ridge. The graben presents up to 3.5 km of base-salt relief at its basinward-bounding fault and internal base-salt horsts up to 1 km high. This compartmentalises deformation, producing extensional and contraction salt structures, ramp-syncline basins and expulsion rollovers within the graben, resulting in a remarkably different and variable style of salt tectonics than in the adjacent areas. We also conduct structural restorations to analyse the spatial and temporal evolution of this complex style of deformation and potential prolonged crustal extension in the Merluza Graben by using discrepancies in the present and restored salt area. This approach affords further constraints on local variations in the relative timing of rifting and salt deposition and its impact on salt tectonics along the margin, which can be applied to other hyper-extended rifted margins worldwide.

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Controls on and Expressions of Submarine Fan Genesis Within a High Accommodation Margin Setting, Santos Basin, Brazil—A High-Resolution Seismic-Stratigraphic and -Geomorphic Case Study

Cited by 6 publications

References 0 publications

The Merluza Graben: How a Failed Spreading Center Influenced Margin Structure, and Salt Deposition and Tectonics in the Santos Basin, Brazil

The Merluza Graben: How a Failed Spreading Center Influenced Margin Structure, and Salt Deposition and Tectonics in the Santos Basin, Brazil

Progradational and backstepping shoreface deposits in the Ladinian to Early Norian Snadd Formation of the Barents Sea

The Merluza Graben: how a failed spreading centre influenced margin structure, salt deposition and tectonics in the Santos Basin, Brazil

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