Chronologic constraints on high-resolution records of the sedimentary and biotic response to the Badenian Salinity Crisis of the Central Paratethys

Hydrological changes had a profound influence on environmental conditions within the Paratethys. The silled nature of the basins that constituted Paratethys made them particularly sensitive to eustatic changes and tectonism leading to frequent isolation. This brought about large fluctuations in water chemistry, which led to a number of regional extinction events, multiple expansions of highly endemic faunas, and the deposition of world-class source rocks. A base-level drop and subsequent strong increase in salinity during the regional Badenian stage led to the extinction of a large number of species and triggered deposition of up to 300 m of evaporites in large parts of the Central Paratethys. This so-called Badenian Salinity Crisis (BSC) was arguably one of the most severe environmental catastrophes striking this aquatic ecosystem. A lack of rigorous age control on tell-tale sedimentary records throughout southeastern Europe nevertheless hampered its thorough understanding.

Recently obtained radio-isotopic (⁴⁰Ar/³⁹Ar), magnetostratigraphic and cyclo-stratigraphic age constraints and an enhanced biostratigraphic control on sections spanning the BSC interval in southern Poland, Romania, Bosnia-Herzegovina and Austria allow for high-resolution correlation of the BSC deposits in different parts of the basin. Detailed descriptions of the sedimentary and biotic response apparent in these stratigraphically calibrated sections elucidate the progression and basin-wide impact of the BSC. The constructed chronostratigraphic framework furthermore allows the placement of this benchmark event in a regional as well as global context, and the discussion of its potential forcing mechanisms.