Early Cambrian tidal deposits of Northwestern Argentina

VANINA LOPEZ DE AZAREVICH; MIGUEL AZAREVICH

Puerto Madryn

Conferencia; Tidalites 2015. 9° International Conference on Tidal Sedimentology; 2015

Asociación Argentina de Sedimentología - CONICET -CENTPAT

The present contribution has the aim of present some results about the study carried out on Neoproterozoic-Early Cambrian shallow-marine deposits of NW Argentina that evidence tidal-influence.Stratigraphic profiles were analyzed in 12 localities along eastern and western margins of the sedimentarybasin (Figure 1).The basement rocks of NW Argentina comprises the Neoproterozoic-Early Cambrian, clastic sedimentary sequence of the Puncoviscana Formation (Turner 1960), deposited along a marine platform that records proliferation of algae and bioturbation. Initiation of deposition occurred once the breakup of Rodinia conduced to the opening of the Puncoviscana Sea between the Río de la Plata and Laurentia (Arequipa-Antofalla according to Omarini et al. 1999) cratons toward the end of the Ediacara Period (latest Neoproterozoic). This tectonic configure ration produced the closure of the Brasilides Ocean due to the convergence of the Río de la Plata and the Marmora Terranes (Frimmel et al. 2011). The presence of Nereites and Oldhamia ichnoassociations suggests an Upper Ediacara to Early Cambrian age of deposition, confirmed by U-Pb zircon ages in interlayered piroclastic rocks.