New insight on upper Silurian-lowermost Devonian conodont biostratigraphy of the Argentine Precordillera and its palaeogeographic implications for the SW Gondwana margin

Abstract

The Cerro del Fuerte section, located in the Central Precordillera of San Juan Province, is considered a reference section to the study of Silurian-Devonian conodont biostratigraphy from Argentina and South America. The conodont association recovered in this section comprises twenty-five conodont taxa (species and sub-species) belonging to ten genera which allowed to record six conodont biozones from the Ludlow, Pridoli, and the Early Devonian (Lochkovian). Based on this new conodont biostratigraphy we propose constraining the brachiopod biostratigraphy reported in the same section. The Lau Event is probably recorded in the middle levels of the Los Espejos Formation where a change in the conodont fauna is verified. Despite that during the late Silurian and Early Devonian, the Argentina Precordillera was located at high southern latitudes in southwest Gondwana, the conodont fauna studied are composed of geographically widespread taxa supporting that the late Silurian – early Devonian was a time interval with minimal conodont provincialism.