The Late-Quaternary deposits of the Piedra Buena Terrace (Patagonian continental slope, SW Atlantic): An example of interaction between bottom currents and seafloor morphology

Isola, José Ignacio; Bravo, María Emilia; Bozzano, Graziella; Palma, Fermín; Ormazabal, Juan Pablo; Principi, Sebastián; Spoltore, D.; Martín, Rodrigo S.; Esteban, Federico Damián; Tassone, Alejandro Alberto

doi:10.1016/j.margeo.2021.106459

Cited by 13 publications

(13 citation statements)

References 48 publications

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“…Fluid migration linked to seafloor depressions has been reported in different areas along the southwestern Atlantic continental margin. Subcircular depressions and acoustic anomalies have been documented at the Patagonian continental margin (Muñoz et al, 2012;Muñoz et al, 2013;Isola et al, 2020;Isola et al, 2021). In accordance with previous work by Jané et al (2010) and Roy et al (2014), they proposed that vertical diffuse fluid flow in permeable strata above faults constrained the pockmark distribution and appearance.…”

Section: Evidence Of Gas Occurrence and Vertical Fluid Flowsupporting

confidence: 77%

“…Both studied seafloor depressions exhibit quite remarkable differences in their shapes and unique infill structures that are significantly different from most other known large-scale seafloor depressions. In most cases, they display a more simple internal structure, which often comprises a distinct depression flank and mounded sediment drift deposits infilling the depression at the downcurrent slope as observed on the Chatham Rise (e.g., Hillman et al, 2018;Klaucke et al, 2018), in the Korea Strait (Cukur et al, 2019), or in small-scale at the Patagonian continental slope (Isola et al, 2021). In contrast, a recent study proposed a prograding infill on the upcurrent and erosion on the downcurrent depression flank (Wenau et al, 2021), showing that opposing current flow directions can result in similar crescentshaped depressions.…”

Section: Depressions Indicate Locally Dynamic Current Regime At Bmcmentioning

confidence: 99%

“…Especially in hydrodynamically energetic oceanographic settings, seafloor depressions are maintained and reshaped by bottom currents (García et al, 2016a;Hillman et al, 2018;Klaucke et al, 2018;Miramontes et al, 2019a;Cukur et al, 2019;Isola et al, 2020;Isola et al, 2021). Recent studies on the Falkland/Malvinas Terrace (Nicholson and Stow, 2019) and Piedra Buena Terrace (Isola et al, 2021) have documented circular to elliptical seafloor depressions with distinct sediment deposition on the downstream slope. This interaction of depression with bottom currents has previously been shown using numerical modeling (Hammer et al, 2009) and tank experiments (Pau et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime

et al. 2023

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Seafloor depressions (SD) are features commonly observed on the ocean floor. They often occur as circular, small-sized (up to 10 s of m) incisions caused by fluid expulsion. Larger depressions (100s m to km) are considerably less abundant, and their origin and development have been scarcely studied. This study investigated two giant morphological depressions (>5 km) using recently acquired multibeam bathymetry and backscatter, sediment echosounder, and high-resolution seismic data. An arc-shaped (SD-N) and a sub-circular depression (SD-S) are located on the Ewing Terrace at the Argentine Continental Margin north and south of the Mar del Plata Canyon, respectively. The study area is influenced by the Brazil-Malvinas Confluence, where major counterflowing ocean currents affect sedimentation, and northward flowing currents form a large contourite depositional system. Using an existing seismo-stratigraphy, the onset of SD-N was dated to the middle Miocene (∼15–17 Ma), whereas SD-S started developing at the Miocene/Pliocene boundary (∼6 Ma). Acoustic anomalies indicate the presence of gas and diffuse upward fluid migration, and therefore seafloor seepage is proposed as the initial mechanism for SD-S, whereas we consider a structural control for SD-N to be most likely. Initial depressions were reworked and maintained by strong and variable bottom currents, resulting in prograding clinoform reflection patterns (SD-N) or leading to the build-up of extensive cut-and-fill structures (SD-S). Altogether, this study highlights the evolution of two unique and complex seafloor depressions throughout the geologic past under intense and variable bottom current activity in a highly dynamic oceanographic setting.

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Section: Evidence Of Gas Occurrence and Vertical Fluid Flowsupporting

confidence: 77%

Section: Depressions Indicate Locally Dynamic Current Regime At Bmcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime

et al. 2023

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“…Besides these conspicuous morphosedimentary features, the PCM hosts a vast canyon system (Ewing & Lonardi, 1971; Lastras et al , 2011; Bozzano et al , 2017), which comprises seven main canyons and more than 50 tributary canyons between 500 and 1800 m. These canyons cut the Nágera and Perito Moreno terraces and eventually indent the shelfbreak (Lastras et al , 2011). To the east, the canyon system continues through the Piedra Buena Terrace and finally conveyed into a contouritic channel at the boundary between Piedra Buena and Valentín Feilberg terraces at water depths of ∼3500 m (Hernández-Molina et al , 2010; Isola et al , 2021).…”

Section: Oceanographic and Geological Settingsmentioning

confidence: 99%

“…2) Schematic hydrographic section showing the main intermediate and deep water masses that interact with the seafloor at 45°S: AAIW : Antarctic Intermediate Water; UCDW : Upper Circumpolar Deep Water; LCDW : Lower Circumpolar Deep Water; AABW : Antarctic Bottom Water. (Modified after Isola et al , 2021).…”

mentioning

confidence: 99%

Enhanced Primary Productivity in the Brazil Malvinas Confluence Zone during the Mis 3

Laprida¹,

Albarracín²,

Romero³

et al. 2023

Ameghiniana

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Micropaleontological analyses from the western South Atlantic core AU_Geo02_GC20 (45° 55' S; 58° 30' W, 2589 m water depth) revealed changes in the primary productivity and sea surface temperature (SST) during MIS 3 that point to significant changes in the Brazil Malvinas Confluence Zone dynamics. These changes led to a marked increase in the SST and the primary productivity between 44.0–36.1 ka BP, as indicated by the quantitative reconstruction of the subsurface temperature and the high relative abundance of the planktonic foraminifera Globigerina bulloides and the eutrophic index. The increase in the SST and the primary productivity could indicate frequent or more persistent southward penetration of subtropical waters over the north Patagonian margin due to a southward extension of the Brazil Current and a weakening of the Malvinas Current. The high primary productivity resulted in the intensive use of phosphate during spring. Conversely, benthic assemblages do not reflect high surface productivity. The dominance of calcareous nannoplankton over diatoms as primary producers, which allows inferring the shoaling of the nutricline and the thermocline, justifies the decoupling between planktonic and benthic communities as a consequence of reduced efficiency of the biological pump. The deposition of the pelagites during the period of enhanced primary productivity indicates a slowing down of the bottom circulation, probably due to a weakening of the Atlantic Meridional Overturning Circulation.

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Discovery of deep-sea cold seeps from Argentina host singular trophic linkages and biodiversity

Bravo,

Principi,

Levin

et al. 2024

Deep Sea Research Part I: Oceanographic Research Papers

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The Late-Quaternary deposits of the Piedra Buena Terrace (Patagonian continental slope, SW Atlantic): An example of interaction between bottom currents and seafloor morphology

Cited by 13 publications

References 48 publications

Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime

Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime

Enhanced Primary Productivity in the Brazil Malvinas Confluence Zone during the Mis 3

Discovery of deep-sea cold seeps from Argentina host singular trophic linkages and biodiversity

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