MACROEVOLUTIONARY TRENDS AND PALAEOENVIRONMENTAL CHANGES DURING THE EARLY TOARCIAN MASS EXTINCTION IN BULGARIA

The early Toarcian mass extinction was one of the most important biotic crises of the Mesozoic era, with severe disruptions in the marine realm resulting in the loss of 15-20% of marine families and genera. This event is closely linked to the Karoo-Ferrar Large Igneous Province, the postulated driving mechanism for severe contemporary geochemical perturbations leading to anoxia and extinction. Despite the global nature of the extinction event, the majority of existing records come from North-Western European epicontinental sedimentary sections. We will present new quantitative palaeoecological and facies data, alongside geochemical records (Sr, C and O, carbonate and organic), from more easterly Tethyan Lower Jurassic sections in North-West Bulgaria collected during two field seasons in 2015. These data document major sea level fluctuations and track macroevolutionary trends of marine shelf ecosystems from an area closer to the open Tethys Ocean. A lack of black shales in Bulgarian sections, which are well recognised during the Toarcian time interval in the North-West European Boreal Realm, suggests there was a much weaker manifestation of anoxia in the region.