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  • 1
    Online-Ressource
    Online-Ressource
    The Argentina Continental Margin : A Potential Paleoclimatic-Paleoceanographic Archive for the Southern Ocean. (2017)
    Cham :Springer International Publishing AG,
    Details
    Schlagwort(e): Paleontology. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (129 pages)
    Ausgabe: 1st ed.
    ISBN: 9783319041964
    Serie: SpringerBriefs in Earth System Sciences Series
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=4830525
    DDC: 551.4680982
    Sprache: Englisch
    Anmerkung: Intro -- Contents -- Abbreviations -- List of Figures -- List of Tables -- Abstract -- 1 Introduction -- Abstract -- 2 Continental Margins in the Global Context -- Abstract -- References -- 3 The Argentina Continental Margin: Location and Significance -- Abstract -- 3.1 Geotectonic Considerations, Types of Margins and Stratigraphy -- 3.1.1 Brief History of the Margin Evolution in the Context of the Southern Hemisphere -- 3.1.2 Margin Types and Geotectonic Configuration -- 3.1.3 Stratigraphic Evidences of the Margin Evolution -- References -- 4 Morphosedimentary Configuration of the Argentina Continental Margin -- Abstract -- 4.1 Coastal Plains -- 4.2 Continental Shelf -- 4.3 Shelf Break -- 4.4 Slope -- 4.5 Rise -- 4.6 Submarine Canyons -- 4.7 Argentine Basin -- References -- 5 Climate and Oceanographic Background -- Abstract -- 5.1 Regional Climate Background -- 5.1.1 Intertropical Convergence Zone -- 5.1.2 South American Monsoon System -- 5.1.3 Southern Hemisphere Westerlies -- 5.1.4 South Atlantic Convergence Zone -- 5.2 Oceanographic Background -- 5.2.1 The Western South Atlantic and the Meridional Overturning Circulation -- 5.2.2 Western South Atlantic Main Currents -- 5.2.3 Western South Atlantic Hydrographic Structure -- References -- 6 Principles of Paleoceanographic Reconstruction -- Abstract -- 6.1 Paleoceanography and Proxy Data -- 6.2 Climate Proxies -- 6.3 Biological Proxies: Fossils as Paleoceanographic Proxies -- 6.3.1 Foraminiferida -- 6.3.2 Coccolithophorids -- 6.3.3 Dinoflagellates -- 6.3.4 Diatoms -- 6.3.5 Radiolarians -- 6.3.6 Corals -- 6.3.7 Ostracods -- 6.3.8 Mollusks -- 6.4 Biomarkers as Paleoceanographic Proxies -- 6.4.1 Alkenones -- 6.4.2 N-Alkyl-Lipids -- 6.5 Geological Proxies -- 6.5.1 Geomorphology -- 6.5.2 Sedimentary Architecture and Structures -- 6.5.3 Physical Properties -- 6.5.4 Geochemical Properties -- References. , 7 State of the Art in the Paleoceanographic Reconstructions at the Argentina Continental Margin -- Abstract -- 7.1 Reconstructions in the Continental Shelf -- 7.2 Reconstructions in the Slope and Rise -- 7.2.1 Paleoceanographic and Biostratigraphic Background Offshore the Argentina Continental Margin -- 7.2.2 Geomorphological Records -- 7.2.3 Sedimentary Architecture and Structures as Records -- 7.2.4 Physical Proxies -- 7.2.5 Geochemical Proxies -- References -- 8 Conclusions -- Abstract -- Further Readings.
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  • 2
    Online-Ressource
    Online-Ressource
    The Argentina Continental Margin : A Potential Paleoclimatic-Paleoceanographic Archive for the Southern Ocean (2017)
    Cham : Springer
    Details Verfügbarkeit
    Schlagwort(e): Earth sciences ; Paleontology ; Sedimentology ; Oceanography ; Geomorphology ; Earth Sciences ; Argentinien ; Schelfmeer ; Schelf ; Geologie ; Falklandinseln ; Süd-Orkney-Inseln ; Südgeorgien ; Süd-Sandwich-Inseln ; Schelf ; Geologie
    Beschreibung / Inhaltsverzeichnis: The evolution of the Argentina Continental Margin during the Quaternary and the stratigraphic and morphosedimentary configuration responded to climatic variability, oceanographic changes, glacioeustatic fluctuations and tectono-isostatic processes, which began to impact on the margin during previous geological periods. The final modeling of the margin was achieved in the late Miocene, when the interaction between the Antarctic and North Atlantic water-masses favored climatic and oceanographic changes with a profound effect on morphosedimentary features. In the Quaternary, the different regions of the margin distinctly responded to such changes. Whereas in the shelf the main modeling factors were the sea-level fluctuations of glacioeustatic origin and consequent marine-continental stratigraphic records, in the slope (particularly in the sector corresponding to the passive margin) the prevailing effect was the interaction between water-masses and the sea floor, giving origin to contouritic depositional systems accompanied of gravity processes responsible of turbiditic and mass-wasting deposits. Different relationships between contouritic and turbiditic facies respond to distinct combinations of oceanic circulation variability and the indirect effect on the sea floor of sea-level fluctuations. As a result of this complexity in the regional processes in the framework of the broad hemispheric oceanographic-climatic conditioning factors, the ACM can be considered as a complete archive for the Southern Ocean
    Materialart: Online-Ressource
    Seiten: Online-Ressource (XV, 117 p. 15 illus., 13 illus. in color, online resource)
    ISBN: 9783319041964
    Serie: SpringerBriefs in Earth System Sciences
    URL: https://doi.org/10.1007/978-3-319-04196-4
    DOI: 10.1007/978-3-319-04196-4
    Sprache: Englisch
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  • 3
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    IODP workshop: developing scientific drilling proposals for the Argentina Passive Volcanic Continental Margin (APVCM) – basin evolution, deep biosphere, hydrates, sediment dynamics and ocean evolution (2017)
    Copernicus
    In:  Scientific Drilling, 22 . pp. 49-61.
    Details
    Publikationsdatum: 2017-11-01
    Beschreibung: The Argentine margin contains important sedimentological, paleontological and chemical records of regional and local tectonic evolution, sea level, climate evolution and ocean circulation since the opening of the South Atlantic in the Late Jurassic–Early Cretaceous as well as the present-day results of post-depositional chemical and biological alteration. Despite its important location, which underlies the exchange of southern- and northern-sourced water masses, the Argentine margin has not been investigated in detail using scientific drilling techniques, perhaps because the margin has the reputation of being erosional. However, a number of papers published since 2009 have reported new high-resolution and/or multichannel seismic surveys, often combined with multi-beam bathymetric data, which show the common occurrence of layered sediments and prominent sediment drifts on the Argentine and adjacent Uruguayan margins. There has also been significant progress in studying the climatic records in surficial and near-surface sediments recovered in sediment cores from the Argentine margin. Encouraged by these recent results, our 3.5-day IODP (International Ocean Discovery Program) workshop in Buenos Aires (8–11 September 2015) focused on opportunities for scientific drilling on the Atlantic margin of Argentina, which lies beneath a key portion of the global ocean conveyor belt of thermohaline circulation. Significant opportunities exist to study the tectonic evolution, paleoceanography and stratigraphy, sedimentology, and biosphere and geochemistry of this margin.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.5194/sd-22-49-2017
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  • 4
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    Morphosedimentary and hydrographic features of the northern Argentine margin: The interplay between erosive, depositional and gravitational processes and its conceptual implications (2013)
    Elsevier
    In:  Deep Sea Research Part I: Oceanographic Research Papers, 75 . pp. 157-174.
    Details
    Publikationsdatum: 2019-09-23
    Beschreibung: Bottom currents and their margin-shaping character became a central aspect in the research field of sediment dynamics and paleoceanography during the last decades due to their potential to form large contourite depositional systems (CDS), consisting of both erosive and depositional features. A major CDS at the northern Argentine continental margin was studied off the Rio de la Plata River by means of seismo- and hydro-acoustic methods including conventional and high-resolution seismic, parametric echosounder and single and swath bathymetry. Additionally, hydrographic data were considered allowing jointly interpretation of morphosedimentary features and the oceanographic framework, which is dominated by the presence of the dynamic and highly variable Brazil-Malvinas Confluence. We focus on three regional contouritic terraces identified on the slope in the vicinity of the Mar del Plata Canyon. The shallowest one, the La Plata Terrace (similar to 500 m), is located at the Brazil Current/Antarctic Intermediate Water interface characterized by its deep and distinct thermocline. In similar to 1200 m water depth the Ewing Terrace correlates with the Antarctic Intermediate Water/Upper Circumpolar Deep Water interface. At the foot of the slope in similar to 3500 m the Necochea Terrace marks the transition between Lower Circumpolar Deep Water and Antarctic Bottom Water during glacial times. Based on these correlations, a comprehensive conceptual model is proposed, in which the onset and evolution of contourite terraces is controlled by short- and long-term variations of water mass interfaces. We suggest that the terrace genesis is strongly connected to the turbulent current pattern typical for water mass interfaces. Furthermore, the erosive processes necessary for terrace formation are probably enhanced due to internal waves, which are generated along strong density gradients typical for water mass interfaces. The terraces widen through time due to locally focused, partly helical currents along the steep landward slopes and more tabular conditions seaward along the terrace surface. Considering this scheme of contourite terrace development, lateral variations of the morphosedimentary features off northern Argentina can be used to derive the evolution of the Brazil-Malvinas Confluence on geological time scales. We propose that the Brazil-Malvinas Confluence in modern times is located close to its southernmost position in the Quaternary, while its center was shifted northward during cold periods
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.dsr.2012.12.013
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  • 5
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    Sedimentary growth pattern on the northern Argentine slope: The impact of North Atlantic Deep Water on southern hemisphere slope architecture (2012)
    Elsevier
    In:  Marine Geology, 329-331 . pp. 113-125.
    Details
    Publikationsdatum: 2017-08-08
    Beschreibung: Large sedimentary deposits consisting of several major contourite drifts were studied by means of high-resolution multichannel seismic data at the middle slope along the Northern Argentina Continental Margin to determine their evolutionary stages as well as to identify and assess the possible impact of Northern Source Deep Water (NSDW) on the slope architecture. The imaged contouritic sediments allow decoding on the regional paleo-oceanographic setting of the last 32 Ma. Earliest contouritic sedimentation can be observed close to the Eocene/Oligocene boundary based on an aggradational stacking pattern with a complex and wavy seismic facies, pointing toward a hydrodynamically turbulent flow pattern. This facies is most likely related to the opening of the Drake Passage associated with global cooling and a strengthening of surface, intermediate and deep ocean currents in the Southern Ocean. During the Middle Miocene plastered drift sequences with an aggradational reflection pattern were deposited. Their depositional style indicates weak, non-turbulent current conditions, which are interpreted to be related to a vertical shift of water mass interfaces caused by the first formation of NSDW during the Mid-Miocene climatic optimum. On top, the formation of plastered drift sequences led to the modern extent of the Ewing Terrace, which was probably controlled by the continuous strengthening and thickening of NSDW until the final closure of the Central American Seaway (CAS). During the Pliocene and Quaternary, after the complete closure of the CAS and under the influence of the full force of the NSDW, mounded plastered drift sequences are built upon the Ewing Terrace generating the modern slope morphology. Therefore, we suggest that deep-water production in the northern hemisphere plays a significant role by controlling the shape of the continental slopes in the southwestern South Atlantic since the Middle Miocene. Highlights ► Slope of northern Argentine Continental margin is current controlled since 32 Ma. ► Variability of Northern Source Deep Water (NSDW) controls sedimentary processes. ► Sedimentary processes are susceptible to changes of the Brazil-Malvinas Confluence. ► Impact of NSDW on slope processes is underestimated in the southern hemisphere.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.margeo.2012.09.009
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  • 6
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    Sediment dynamics and geohazards offshore Uruguay and northern Argentina: first results from the multi-disciplinary Meteor-cruise M78-3 (2010)
    In:  [Poster] In: EGU General Assembly, 02.05.-07.05.2010, Vienna, Austria .
    Details
    Publikationsdatum: 2012-07-06
    Beschreibung: About 90% of the sediments generated by weathering and erosion on land get finally deposited at the ocean margins. The sediment distribution processes and landscape evolution on land are relatively well understood, but comparably little is known about the role and relative importance of marine sediment dynamics in controlling the architectural evolution of ocean margins. Important players include hemi-pelagic settling, down-slope and current-controlled along-slope sediment transport, depositional and post-depositional sedimentary processes (e.g. consolidation and diagenesis), as well as the destabilization of sediment bodies and their erosion. Submarine landslides in this context thus may represent an important sediment transport process, but also a major geo-hazard due to the increasing number of offshore constructions as well as their potential to instantaneously displace large water masses triggering waves in densely populated coastal areas. Here we present first results from a seagoing expedition that aimed at investigating the interaction processes of sediment redistribution, partitioning, deposition and diagenesis from the coast to the deep-sea along the western South-Atlantic passive continental margin. During RV Meteor Cruise M78/3 in May-July 2009 the shelf, slope and rise offshore Argentina and Uruguay have been investigated by means of hydroacoustic and seismic mapping as well as geological sampling with conventional coring tools as well as the new MARUM seafloor drill rig (MeBo) that revealed recovery of geological strata sampled from up to 50m below seafloor. The working area is characterized by a high amount of fluvial input by the Rio de la Plata river. The continental slope is relatively wide and shows average slope gradients between 1 and 2.5 but locally higher slope gradients may occur (〉5). The transition for the continental rise with low slope gradients is found in ~3000 m water depth. The working area is located in a highly dynamic oceanographic regime. Cold Antarctic water masses of the northward flowing Malvina current meet warm water masses of the southward flowing Brazil current in the working area. Various types of sediment instabilities have been imaged in geophysical and core data, documenting particularly the continental slope offshore Uruguay to be locus of frequent submarine landslides. Apart from individual landslides, however, gravitational downslope sediment transport along the continental slope is restricted to the prominent Mar del Plata Canyon and possibly to smaller canyons indentified in the bathymetric data. The location of the canyons might be controlled by tectonics. In contrast, many morphological features (e.g. progradational terraces and slope parallel scarps with scour-geometries) reveal that sediment transport is predominantly influenced/controlled by strong contour bottom currents. This suggests a significant impact of the western boundary currents on the overall architectural evolution of the margin. Future studies using the acquired geophysical, sedimentological, physical property and geochemical data will (i) quantify the relative contribution of gravitational down-slope vs. along-slope processes through time in shaping this ocean margin and how it relates to the global ocean circulation pattern and sea-level change through time, (ii) investigate depositional and post-depositional processes and how they control submarine slope stability and submarine landslide initiation and (iii) explore the interaction and relative contribution of the various processes in controlling margin evolution, sediment dynamics and geohazard off Uruguay and Northern Argentina.
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
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  • 7
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    Sediment dynamics and geohazards off Uruguay and the de la Plata River region (northern Argentina and Uruguay) (2011)
    Springer
    In:  Geo-Marine Letters, 31 . pp. 271-283.
    Details
    Publikationsdatum: 2019-09-23
    Beschreibung: The continental margin off Uruguay and northern Argentina is characterized by high fluvial input by the de la Plata River and a complex oceanographic regime. Here we present first results from RV Meteor Cruise M78/3 of May–July 2009, which overall aimed at investigating sediment transport processes from the coast to the deep sea by means of hydroacoustic and seismic mapping, as well as coring using conventional tools and the new MARUM seafloor drill rig (MeBo). Various mechanisms of sediment instabilities were identified based on geophysical and core data, documenting particularly the continental slope offshore Uruguay to be locus of submarine landsliding. Individual landslides are relatively small with volumes 〈2km3. Gravitational downslope sediment transport also occurs through the prominent Mar del Plata Canyon and several smaller canyons. The canyons originate at a midslope position, and the absence of buried upslope continuations strongly suggests upslope erosion as main process for canyon evolution. Many other morphological features (e.g., slope-parallel scarps with scour geometries) and abundant contourites in a 35-m-long MeBo core reveal that sediment transport and erosion are controlled predominantly by strong contour currents. Despite numerous landslide events, their geohazard potential is considered to be relatively small, because of their small volumes and their occurrence at relatively deep water depths of more than 1,500 m.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1007/s00367-011-0232-4
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  • 8
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    Neodymium isotopic data, radiocarbon dates and calibrated ages of sediment samples off the La Plata Estuary, southeastern South America (2014)
    PANGAEA
    In:  Supplement to: Lantzsch, Hendrik; Hanebuth, Till J J; Chiessi, Cristiano Mazur; Schwenk, Tilmann; Violante, Roberto (2014): The high-supply, current-dominated continental margin of southeastern South America during the late Quaternary. Quaternary Research, 81(2), 339-354, https://doi.org/10.1016/j.yqres.2014.01.003
    Details
    Publikationsdatum: 2023-03-03
    Beschreibung: The continental margin off the La Plata Estuary (SE South America) is characterized by high fluvial sediment supply and strong ocean currents. High-resolution sediment-acoustic data combined with sedimentary facies analysis, AMS-14C ages, and neodymium isotopic data allowed us to reconstruct late Quaternary sedimentary dynamics in relation to the two major sediment sources, the La Plata Estuary and the Argentine margin. Sediments from these two provinces show completely different dispersal patterns. We show that the northward-trending La Plata paleo-valley was the sole transit path for the huge volumes of fluvial material during lower sea levels. In contrast, material from the Argentine margin sector was transported northwards by the strong current system. Despite the large sediment volumes supplied by both sources, wide parts of the shelf were characterized by either persistent non-deposition or local short-term depocenter formation. The location and formation history of these depocenters were primarily controlled by the interplay of sea level with current strength and local morphology. The high sediment supply was of secondary importance to the stratigraphic construction, though locally resulting in high sedimentation rates. Thus, the shelf system off the La Plata Estuary can be considered as a hydrodynamic-controlled end-member.
    Schlagwort(e): Center for Marine Environmental Sciences; MARUM
    Materialart: Dataset
    Format: application/zip, 2 datasets
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  • 9
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    Interaction of a deep-sea current with a blind submarine canyon (Mar del Plata Canyon, Argentina) (2019)
    PANGAEA
    In:  Supplement to: Warratz, Grit; Schwenk, Tilmann; Voigt, Ines; Bozzano, Graziella; Henrich, Rüdiger; Violante, Roberto; Lantzsch, Hendrik (2019): Interaction of a deep-sea current with a blind submarine canyon (Mar del Plata Canyon, Argentina). Marine Geology, 417, 106002, https://doi.org/10.1016/j.margeo.2019.106002
    Details
    Publikationsdatum: 2023-03-03
    Beschreibung: The Mar del Plata (MdP) Canyon at the Argentine continental margin is incorporated into a major contourite depositional system, built by the incursion of southern-sourced water masses affecting the seafloor at different waters depths. The new sedimentological, morphological and hydro acoustic data provide novel insights into contour and turbidity current interactions in mid-slope (blind) canyons, which do not have a connection to the shelf or an onshore river system. Such canyons are capable to record climate-related ocean stratification changes, current variability, and slope stability. Three sediment cores were obtained along the MdP Canyon thalweg covering the last 20,000 years and compiled with two cores from the adjacent Ewing Terrace. Turbidity-current activity within the MdP Canyon was limited to the time interval from Last Glacial Maximum (LGM) to the late deglacial. During the LGM and early deglacial, turbidites reached both the proximal sector and the distal northern flank of the canyon. During the late deglacial only the proximal sector was characterized by turbidite deposition. Similarities in mineralogy and grain-size data indicate that the material transported by the turbidity currents originated from the mid-slope Ewing Terrace. Glacial turbidity-current activity was most probably favored by increased sediment supply along the Ewing Terrace from a shallowed and/or enhanced glacial Antarctic Intermediate Water (AAIW) nepheloid layer. These sediments were trapped by the MdP Canyon, in particular at the head area. During the late deglacial, a displacement or limited AAIW nepheloid layer resulted in less sediment transfer along the Ewing Terrace and immediate accumulation in the MdP Canyon head restricting turbidite deposition to the proximal sector of the canyon. In general, contourite-turbidite interactions provide valuable information on variations in thermohaline circulation such as AAIW distribution and current strength.
    Schlagwort(e): Argentina; Center for Marine Environmental Sciences; contourite; Mar del Plata Canyon; MARUM; turbidite
    Materialart: Dataset
    Format: application/zip, 5 datasets
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  • 10
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    Age and magnetic susceptibility of sediment core GeoB13861-1 (2019)
    PANGAEA
    Details
    Publikationsdatum: 2024-02-02
    Schlagwort(e): 494; AGE; Argentina; Center for Marine Environmental Sciences; contourite; DEPTH, sediment/rock; GC; GeoB13861-1; Gravity corer; M78/3B; Magnetic susceptibility; Mar del Plata Canyon; MARUM; Meteor (1986); turbidite
    Materialart: Dataset
    Format: text/tab-separated-values, 506 data points
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