Ordovician conodonts from Peru: new data and reappraisal - [Poster]

Abstract

Ordovician conodont faunas are poorly known from the northern part of the Central Andean Basin, in contrast with data from the northwest of Argentina and south of Bolivia, areas located in the southern part of the same basin. A single occurrence of late Floian conodonts of the upper Oepikodus evae Zone was reported in 2008 from the Carcel Puncco section (Inambari River valley) of southwestern Peru, close to the Subandean Fault. Further research in the Eastern Cordillera of Peru led to the discovery of three additional occurrences of Early to Middle Ordovician conodonts, also in the San José Formation but representative of different horizons. The first of them consists of an assemblage belonging to the Trapezognathus diprion–Baltoniodus cf. triangularis zones (late Floian), and was characterised in the Kimbiri section (Apurímac River valley). The remaining Abra de Yanacocha and Huancampa localities provided much younger assemblages, representative of the Lenodus variabilis–Yangtzeplacognathus crassus zones (early–middle Darriwilian). Early Ordovician conodonts from Peru display palaeobiogeographic affinities with similar assemblages known from Baltica, South China and northwestern Argentina, whereas the Middle Ordovician occurrences bear resemblances with coeval assemblages from Baltica, central South China and the Argentinean Precordillera