Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime
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....
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2023.1117013/full |
| _version_ | 1811169445146525696 |
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| author | Fynn Warnke Tilmann Schwenk Tilmann Schwenk Elda Miramontes Elda Miramontes Volkhard Spiess Volkhard Spiess Stefan Wenau Stefan Wenau Graziella Bozzano Graziella Bozzano Michele Baqués Michele Baqués Sabine Kasten Sabine Kasten Sabine Kasten |
| author_facet | Fynn Warnke Tilmann Schwenk Tilmann Schwenk Elda Miramontes Elda Miramontes Volkhard Spiess Volkhard Spiess Stefan Wenau Stefan Wenau Graziella Bozzano Graziella Bozzano Michele Baqués Michele Baqués Sabine Kasten Sabine Kasten Sabine Kasten |
| author_sort | Fynn Warnke |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-10T16:43:35Z |
| format | Article |
| id | doaj.art-b7a24c6830f2423da8a09e74d537244e |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-10T16:43:35Z |
| publishDate | 2023-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-b7a24c6830f2423da8a09e74d537244e2023-02-08T04:54:04ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632023-02-011110.3389/feart.2023.11170131117013Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regimeFynn Warnke0Tilmann Schwenk1Tilmann Schwenk2Elda Miramontes3Elda Miramontes4Volkhard Spiess5Volkhard Spiess6Stefan Wenau7Stefan Wenau8Graziella Bozzano9Graziella Bozzano10Michele Baqués11Michele Baqués12Sabine Kasten13Sabine Kasten14Sabine Kasten15Faculty of Geosciences, University of Bremen, Bremen, GermanyFaculty of Geosciences, University of Bremen, Bremen, GermanyMARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyFaculty of Geosciences, University of Bremen, Bremen, GermanyMARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyFaculty of Geosciences, University of Bremen, Bremen, GermanyMARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyFaculty of Geosciences, University of Bremen, Bremen, GermanyFraunhofer Institute for Wind Energy Systems IWES, Bremen, GermanyDepartment of Oceanography, Argentine Hydrographic Service (SHN), Buenos Aires, ArgentinaCONICET, Buenos Aires, ArgentinaDepartment of Oceanography, Argentine Hydrographic Service (SHN), Buenos Aires, ArgentinaAcoustic Propagation Department, Argentinian Navy Research Office and UNIDEF (National Council of Scientific and Technical Research—Ministry of Defense), Buenos Aires, ArgentinaFaculty of Geosciences, University of Bremen, Bremen, GermanyMARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, GermanyAlfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, GermanySeafloor 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.https://www.frontiersin.org/articles/10.3389/feart.2023.1117013/fullgiant seafloor depressionbottom currentscut-and-fill structuresArgentine continental marginreflection seismicfluid expulsion |
| spellingShingle | Fynn Warnke Tilmann Schwenk Tilmann Schwenk Elda Miramontes Elda Miramontes Volkhard Spiess Volkhard Spiess Stefan Wenau Stefan Wenau Graziella Bozzano Graziella Bozzano Michele Baqués Michele Baqués Sabine Kasten Sabine Kasten Sabine Kasten Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime Frontiers in Earth Science giant seafloor depression bottom currents cut-and-fill structures Argentine continental margin reflection seismic fluid expulsion |
| title | Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime |
| title_full | Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime |
| title_fullStr | Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime |
| title_full_unstemmed | Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime |
| title_short | Evolution of complex giant seafloor depressions at the northern Argentine continental margin (SW Atlantic Ocean) under the influence of a dynamic bottom current regime |
| title_sort | evolution of complex giant seafloor depressions at the northern argentine continental margin sw atlantic ocean under the influence of a dynamic bottom current regime |
| topic | giant seafloor depression bottom currents cut-and-fill structures Argentine continental margin reflection seismic fluid expulsion |
| url | https://www.frontiersin.org/articles/10.3389/feart.2023.1117013/full |
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