Middle Ordovician conodont biostratigraphy and paleobiogeography from the Suri formation at the Chaschuil region (Famatina System, NW Argentina)

Abstract

The fossil record of the Famatina System of NW Argentina has been extensively studied by several authors, but its conodont fauna is poorly known. This contribution analyses a significant conodont association recovered from the Suri Formation cropping out at Chaschuil region (Catamarca province). Conodonts comprise a low diversity association consisting of four genera and five species of significant regional and global biostratigraphic importance: Baltoniodus cooperi Carlorosi, Sarmiento and Heredia, Baltoniodus triangularis (Lindström), Condorodus gracielae Carlorosi, Mestre and Heredia, Erraticodon patu Cooper and Gothodus costulatus Lindström. This association supports a Dapingian age for the bearing strata (Baltoniodus triangularis Zone), and the correlation of strata with some from northern Argentina and those globally referenced sections. Furthermore, the biostratigraphic patterns, distribution and evolution of the recovered species along with the associated fossils allow us to suggest a paleobiogeographic migration pattern that involved the Andean Basin, the Famatina System and the Precordillera during the latest Early Ordovician and the early Middle Ordovician.