A morphosedimentary characterization of three areas of the Argentine Continental Margin

PALMA F.I.; ORMAZABAL JP; ISOLA, J.I.; BOZZANO, G.; SPOLTORE D.; TASSONE A.; ESTEBAN F. D.

Roma

Conferencia; 34th IAS Meeting of sedimentology; 2019

international Association of Sedimentologists

In the framework of the PAMPA AZUL Project, aprogram launched by the Argentinean Government to deepen into thescientific knowledge of the Argentinean Sea for its conservation andprotection, the Marine Geology Working Group (GTGM) performed,between 2017 and 2018, three oceanographic cruises (Geo0, Geo1 andGeo2)on board the Argentinean R/V Austral. Three sectors of the ArgentineContinental Margin (ACM) - Tierra del Fuego, West Malvinas andPatagonia - have been surveyed with a Kongsberg EM 122swath bathymetry echo sounder and with a Teledyne ATLAS PARASOUND P70sub-bottom profiler. In addition, 33 gravity cores have been obtainedin these areas in water depths that vary from 130 m to 3480 m, thusencompassing from the shelf break to the lower slope. The finalobjective of the GTGM is to undertake a multidisciplinaryinvestigation of the evolution of the ACM during the Late Quaternarywhere sedimentary processes, tectonic control, source-to-sink andpaleoceanographic reconstructions will be integrated. The presentcontribution focuses on the sedimentological information gathered bythe preliminary study of the sediment cores that, together with thebathymetry and seismic profiles, will allow us to identify theprincipal morpho-sedimentary features in the three study areas. Thisis an especially attractive task as the ACM is characterized by acomplex Contourite Deposition System (CDS), originally described byHernandez-Molina et al. (2009), that interact with 5 Submarine CanyonSystems, formerly illustrated by Lonardi and Ewing (1971). In theTierra del Fuego area (~55º S), the most outstanding feature is theSloggett (Sverdrup) Canyon that incises the continental shelf andreaches 3800 m water depth. Here, downslope sedimentary processes andtectonic lineaments probably controlled the canyon inception (Palmaet al., 2018). However, sediment cores from the middle sector of thecanyon contain thick hemipelagic sequences, suitable for detailedpaleoceanographic reconstructions. In the West Malvinas sector (~53ºS), along-slope processes seem to dominate with alternation of sandyand muddy contouritic facies. In the Patagonian sector (~43-47º S),the northwards flowing Antarctic water masses interfere with thePatagonia Canyon Systemgiving rise to a complex set of mixed contouritic-turbiditic facies,in most cases overlain by foram-rich hemipelagic facies. p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 115%; }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 12pt; }