Integration of sequence stratigraphy, sedimentology and ichnology in a chronostratigraphic analysis of the lower Paleozoic of northwest Argentina

Abstract

This set of data suggests a Vendian to Nemakit-Daldynian age for the Puncoviscana Formation, a late Early Cambrian to Middle Cambrian age for the Mesón Group, and a Late Cambrian to Tremadocian age for the Santa Rosita Formation. The Tilcaric Phase, responsible for the angular unconformity between the Puncoviscana Formation and the Mesón Group, is regarded as intra-Early Cambrian. The contact between the Mesón Group and the Santa Rosita Formation is represented by an unconformity (sequence boundary) due to a relative sea level fall that took place near the Middle to Late Cambrian transition. Late Cambrian sedimentation was initially restricted to the axis of fluvio-estuarine paleovalleys and subsequently expanded during a basinwide transgression.