Lower Jurassic sedimentary successions from the Neuquén Basin, Argentina are unique in the abundance of radiometrically datable material (ash-beds) present, which can be tied to bio- and chemostratigraphic (carbon-isotope) zonations. Here, we present newly integrated carbon-isotope and Hg/TOC data from three localities in Argentina (Arroyo Lapa, Arroyo Serrucho/Las Overas and Chacay Melehue) to generate a biostratigraphically calibrated composite carbon-isotope curve and geochronological framework for the Pliensbachian–Toarcian transition in South America. Using a Bayesian framework we present an age-depth model for this composite record and estimate the age and duration of key intervals extending from the Latest Pliensbachian carbon-isotope excursion (CIE) through the Early Toarcian negative CIE associated with the Toarcian Oceanic Anoxic Event (T-OAE).
This geochronological framework is subsequently combined with a statistical analysis of all available Karoo and Ferrar Large Igneous Province (LIP) radioisotopic ages to create a timeline of the key events in the Pliensbachian–Toarcian and their association with emplacement of intrusive and extrusive igneous rocks of the Karoo and Ferrar LIPs.
| Subject : | : | oral |
| Topics | : | SC8: The Jurassic: events, correlation and timescale |
| Keywords | : | Pliensbachian–Toarcian ; Carbon Isotope Excursions ; Early Jurassic ; Large Igneous Province ; Geochronology |
| PDF version | : |  PDF version |
