Triassic/Jurassic bivalve extinction and recovery in the Neuquén Basin, Argentina

Abstract

The extinction event at the end of the Triassic is one of the “big five” global crisis in the history of life in the marine realm. Nevertheless, that extinction and the subsequent biotic recovery are not so well known as others, and most of the published analyses were based on data from the Northern Hemisphere. Bivalves are one of the best studied groups in relation to the recovery after the end-Triassic extinction event. We analyze the Late Triassic extinction and Early Jurassic recovery of bivalve faunas within marine environments in the Atuel river area of the Neuquén Basin, Argentina (Riccardi et al., 1988; Lanés, 2005). The nearly continuous presence of marine stenohaline major taxa such as cnidarians, rhynchonelliform brachiopods, echinoderms and cephalopods indicate normal salinity (Damborenea & Mancenido, 2005). Data were collected from a thick and exceptionally well-exposed latest Triassic-earliest Jurassic section of the Andes, which allows a highresolution reconstruction of the local diversity dynamics.