Elongated Giant Seabed Polygons and Underlying Polygonal Faults as Indicators of the Creep Deformation of Pliocene to Recent Sediments in the Grenada Basin, Caribbean Sea

Gay, Aurélien; Padrón, Carlos; Meyer, Solène; Beaufort, Daniel; Oliot, Émilien; Lallemand, Serge; Marcaillou, Boris; Philippon, Mélody; Cornée, Jean‐Jacques; Audemard, Franck; Lebrun, Jean‐Frédéric; Klingelhoëfer, Frauke; Lépinay, Bernard Mercier de; Münch, Philippe; Garrocq, Clément; Boucard, Milton; Schenini, Laure

doi:10.1029/2021gc009809

Cited by 6 publications

(9 citation statements)

References 103 publications

(150 reference statements)

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“…This second phase of extension is chronologically consistent with subsidence in the NLA forearc and the intra-arc Kalinago basin (0.34 mm yr −1 ; Boucard et al 2021;Cornée et al 2021), as well as subsidence in the central part of the arc (offshore Guadeloupe; De Min et al 2015). Recent estimates of NW-SE extension based on polygonal fault orientations indicate that the NLA backarc is submitted to similar processes as the arc and forearc (Gay et al 2021). Estimates of backarc extension show a change from EW to SSE-NNW towards the south, while post-mid-Miocene subsidence is observed there as well, with increasing rates towards the southernmost part of the margin since Late Miocene (i.e.…”

Section: O N G -T E R M S U B S I D E N C E a L O N G T H E E N T I R...supporting

confidence: 61%

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen

Calais

Jolivet

et al. 2022

Geophysical Journal International

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Summary Geological estimates of vertical motions in the central part of the Lesser Antilles show subsidence on timescales ranging from 125.000 to 100 years, which has been interpreted to be caused by interseismic locking along the subduction megathrust. However, horizontal GNSS velocities show that the Lesser Antilles subduction interface is currently building up little to no elastic strain. Here we present new present-day vertical velocities for the Lesser Antilles islands and explore the link between short- and long-term vertical motions and their underlying processes. We find a geodetic subsidence of the Lesser Antilles island arc at 1-2 mm/yr, consistent with the ∼100-year trend derived from coral micro-atolls. Using elastic dislocation models, we show that a locked or partially-locked subduction interface would produce uplift of the island arc, opposite to the observations, hence supporting a poorly-coupled subduction. We propose that this long-term, margin-wide subsidence is controlled by slab dynamic processes, such as slab rollback. Such processes could also be responsible for the aseismic character of the subduction megathrust.

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Section: O N G -T E R M S U B S I D E N C E a L O N G T H E E N T I R...supporting

confidence: 61%

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen

Calais

Jolivet

et al. 2022

Geophysical Journal International

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“…On a nearly aclinal seafloor, the bottom-current erosion would be stronger at the downstream flanks (or reaches), shown as the erosion of single pockmark (Figure 6) or pockmark train (Figure 7), which is consistent with the current erosion mainly occurred at the downstream of an arc-shaped and elongated depression (with a length of 30 km), at the northern Argentine continental margin (Warnke et al, 2023). In the Grenada Basin (Gay et al, 2021) and the Hatton Basin (Berndt et al, 2012), the wide development of giant polygonal faults on the seabed may induce a stronger bottom-current erosion between the neighbouring polygons, forming seafloor furrows with a flat bottom.…”

Section: Channel Inception Induced By Bottom Currentssupporting

confidence: 61%

“…In the present study, we focus on the interaction between bottom currents and depressions formed by fluid escape, but similar results could apply to other kind of negative-relief bedforms formed by other factors, such as faulting (Berndt et al, 2012;Gay et al, 2021) and sediment dissolution (Cavailhes et al, 2022;Kluesner et al, 2022). On a nearly aclinal seafloor, the bottom-current erosion would be stronger at the downstream flanks (or reaches), shown as the erosion of single pockmark (Figure 6) or pockmark train (Figure 7), which is consistent with the current erosion mainly occurred at the downstream of an arc-shaped and elongated depression (with a length of 30 km), at the northern Argentine continental margin (Warnke et al, 2023).…”

Section: Channel Inception Induced By Bottom Currentsmentioning

confidence: 75%

Channel inception through bottom‐current erosion of pockmarks revealed by numerical simulation

Lefebvre

Düring

et al. 2023

Earth Surf Processes Landf

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In deep‐marine environments, the inception of channels can be induced by the interaction between bottom currents and rough topography. However, it is still unclear under which conditions such features can form and what happens in the earliest phase of channel development. In this study, based on the morphological, sedimentary and oceanographic settings of a pockmark field in the NW South China Sea, we reveal the process of channel inception through the erosion of pockmarks by bottom currents. Using numerical simulations, we show that an appropriate current velocity can induce the erosion of pockmark trains in cohesive sediments, leading to the coalescence of discrete pockmarks and the formation of a channel with a rough thalweg. The interaction of bottom currents with the pockmarks induces a significant erosion along the pockmarks axis. Bottom‐current erosion is strongest at the downstream edges of pockmarks, where the horizontal velocity reaches a maximum and an upwelling forms. Erosion increases as the distance between pockmarks reduces. In our simulation results, a channel is only formed by the coalescence of pockmarks if the distance between pockmarks is <6 times the diameter of the pockmark. This study provides evidence of the formation of channels by bottom currents, which helps reconstruct palaeoceanographic conditions based on sediment architecture. It also shows the complex hydrodynamics at these structures that strongly control sedimentary processes and may affect distribution of benthic ecosystems in marine environments.

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“…Polygonal fault systems have been documented in many basins worldwide as a feature formed by the non-tectonic regime. They are normal faults with polygons geometry in the plan view (Berndt, 2005, Cartwright et al, 2007Løseth et al, 2011;Le, 2021;Gay et al, 2021). The faults are supposed to be formed by sediment loading and heterogeneous volumetric compaction results in small-scale normal faults (Berndt, 2005;Neagu et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…The faults are supposed to be formed by sediment loading and heterogeneous volumetric compaction results in small-scale normal faults (Berndt, 2005;Neagu et al, 2010). Polygonal fault systems are interpreted as layer-bound of deformation and its restricted in the lowpermeability slope and basin plain lithofacies (Cartwright et al, 2007;Gay et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Submarine landslide and associated polygonal faults development: a case study from offshore Norway

Bui²

2023

JMES

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Submarine slide and polygonal faults have been investigated using high-resolution 3D seismic data, over an area of 2,300 km2. The study area is located on the continental slope, offshore Norway. Submarine sliding covers more than half of the study area, and is part of the Storage slide. The slide developed a series of extensional faults at the upper extensional zone which is gradually changed to chaos seismic facies, interpreted as mass transport deposits. There is no clear evidence of compression/contractional zone downslope. Polygonal faults are highly developed in the KS1 and KS2 interval, corresponding to the Lower Miocene age. The fault has small offset of c. 10÷30 ms TWT, spacing ranges between c. 500 m and 1 km. Within this faulted interval, faults tend to develop intensively below the submarine sliding and much less out of that area. Bright amplitude anomalies are observed within the north south – elongated anticline structure. It has been mapped over an area of c. 135 km2 coinciding with the top anticline. Among those, there are two obvious negatives, bright amplitude reflectors which are relatively flat at 2670 ms TWT (flat spot 1) and 2800 ms TWT (flat spot 2). These flat spots are interpreted as hydrocarbon-brine contacts. Flat spot 2 is bounded by the structure contour but there is no evidence for the unconformable with the lithologic reflections from the trap boundary, thus this still needs to be confirmed by well data. Bright amplitude anomalies suggest the existence of hydrocarbon in the trap, in addition, the occurrence of polygonal faults is linked to seal potential covering the underneath petroleum reservoir, proving the great hydrocarbon potential in this area.

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Elongated Giant Seabed Polygons and Underlying Polygonal Faults as Indicators of the Creep Deformation of Pliocene to Recent Sediments in the Grenada Basin, Caribbean Sea

Cited by 6 publications

References 103 publications

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Channel inception through bottom‐current erosion of pockmarks revealed by numerical simulation

Submarine landslide and associated polygonal faults development: a case study from offshore Norway

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