Transgressive Deposits of the Mid-Wisconsin Interstadial from$33\textdegree$to 40° South Latitude, Argentine Republic: Reliability of14CAges

An analysis concerning to the reliability of several14Cages ranging from 25,700$\plusmn$650 BP to 38,500$\plusmn$3000 BP, obtained from raised estuarine and marine deposits found between 33$\plusmn$to 4037° South Latitude is presented. Possible biogenic carbonate contamination by ground water, edaphic development, or crystalline transformation from aragonite to calcite in the shell car- bonates, is analyzed in each dated sample. Also considered are laboratory methodological errors and instrumental limitations. Preliminary magnetostratigraphic results appear to support the reliability of these14Cdates, as do various paleoclimatic and paleomagnetic considerations with a possible cause/effect relationship. /// Presente une analyse concernant la veracite de plusieurs datations au 14C d'age comprise entre 25700 ñ 650 avant nos jours, et 38500 ñ 3000 avant nos jours. Ces analyses proviennent de depots estuariens sureleves et de depots marins situes entre 33θ et 40θ S. Analyse pour chaque echantillon une possible contamination des carbonates biogenes par l'eau du fond, le developpement edaphique ou la transformation des coquilles d'aragonite en calcite. Considere aussi les erreurs des methodes de laboratoires et les limites des instruments. Tout comme les considerations paleo-climatiques et paleomagnetiques, les premiers resultats mag-neto-stratigraphiques semblent confirmer la veracite de ces datations, avec de possibles relations de cause a effet.-Catherine Bressolier, EPHE, AU 910 CRNS, Montrouge, France.