C34/C33 limit in proximal marina Santa Marta Formation and its correlation with distal Rabot Formation in James Ross Basin, Antarctica

MILANESE, FLORENCIA N.; OLIVERO, EDUARDO B.; KIRSCHVINK, JOSEPH L.; RAPALINI, AUGUSTO E.

San Pablo

Congreso; IV Reunión Bienal de la Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo; 2015

The Santa Marta Formation (Santonian - middle Campanian) is located in the northwestern tip of the James Ross Island, in the Antarctic Peninsula. The Rabot Formation (early-middle Campanian), that is equivalent to the upper part of the Santa Marta Formation, crops out at the southeastern sector of the island. Due to diachronic extinctions and endemism, biostratigraphic correlation of the James Ross Basin infill presents many uncertainties. We present here a preliminary magnetostratigraphic composite section of four outcrops of the Santa Marta Formation which suggests that the C34n/C33r reversal, and therefore the SantonianCamapanian boundary, is recorded at the lower levels of the Santa Marta formation. This is consistent with previous magnetostratigraphic results on the Rabot Formation and agrees with biostratigraphic correlations based on ammonites associations