LATE CENOZOIC COLD WATER CORAL FOSSIL CONCENTRATIONS AND MOUNDS IN THE SOUTHWEST SOUTH ATLANTIC

LAPRIDA, C. ; BOZZANO, G.; GARBEROGLIO,R.; VIOLANTE,R.

Ghent

Congreso; 2nd Deep Water Circulation Congress; 2014

Cold-water coral (CWC) ecosystems are among the richest biodiversity hotspots in the deep sea, providing shelter and food for hundreds of associated species. Recent investigations have shown that extensive CWC ecosystems exist along the Argentine continental margin (ACM). A common point of discussion concerns the driving forces regarding the initiation of these complex systems. Both oceanographic boundary conditions (salinity, temperature, nutrient availability, current speed) and geological (i.e. hardground availability) processes have been proposed to play a significant role in the CWC nucleation, growth and decline. An intriguing question is to what extent the occurrence of CWC reefs along the Southwestern Atlantic margin (SWAM) is related to the pathway of the Antarctic Intermediate Water (AAIW). Records of fossil Cenozoic CWC are extremely scarce in the SWAM. However, in the last few years CWC fossil concentrations of Late Pleistocene age were found in deep sea cores from the northern sector of the ACM (Fig. 1). Based on acoustic (multibeam images), sampling (deep-sea cores) and oceanographic data, a morphosedimentary characterization as well as water masses definition have been carried out in order to analyze the main factors controlling the growth and distribution of fossil CWC. We intent to determine: (i) the spatial distribution of the CWC fossil concentrations in the northern sector of ACM; (ii) the influence of the Antarctic Intermediate Water (AAIW) on the distribution of the CWC; and (iii) the role of the hydrodynamic pattern generated flow impinging the slope topography in the spatial distribution of the fossil CWC concentrations.