The Toarcian (Early Jurassic) Jenkyns Event in Hungary: stratigraphic, geochemical, and fossil records and their global implications

Abstract

The Early Toarcian (~183 Ma, Early Jurassic) Jenkyns Event is defined as a series of environmental-climatic changes leading to changes in sedimentary regimes, perturbation of biogeochemical cycles, and a second-order mass extinction. Here, we briefly review the definition of this event and how it is recorded in characteristic sedimentary, palaeontological and geochemical signals all over the world, many of which have been documented in Hungary as well. Lower Toarcian strata are known in two tectonic units in Hungary representing different Tethyan environments: (1) in the Transdanubian Range Unit (TRU) manganiferous intercalations occur in a condensed pelagic limestone succession, and (2) in the Mecsek Basin (MB) of the Tisza Mega-unit (TU) in the form of an organic-rich black shale bed-set within a mixed siliciclastic-carbonate succession. Numerous studies of the Hungarian geological record of the Jenkyns Event have focused on its stratigraphy, sedimentology, palaeontology, geochemistry, and economic geology, leading to insights into biotic changes, geochemical perturbations, weathering regimes, and ore-forming processes, adding much relevant information to our understanding of these global phenomena. Despite such a rich history of investigations, the Toarcian successions in Hungary still offer plenty of opportunities for further research on the Jenkyns Event. Spearheading the Jurassic studies in Hungary for the past several decades, András Galácz and Attila Vörös have not only made an immense contribution but also inspired many researchers in their endeavours. This article pays tribute to their outstanding scientific career.