End-Permian Mass Extinction and its Aftermath in Boreal Waters Reflected by Foraminifera from Spitsbergen

Abstract

The end-Permian mass extinction and subsequent recovery of foraminifera from high northern latitudes is poorly constrained. Here, we utilise sediment cores drilled in Deltadalen, central Spitsbergen, that span the latest Permian to earliest Triassic including the mass extinction. Foraminiferal species diversity, morphogroups and test size data derived from the core section supplemented by sedimentary data and eco-stratigraphic changes are utilized as environmental proxies. The foraminiferal succession is made up of low diversity agglutinated assemblages reflecting restricted environmental conditions, with hypoxia and reduced access to carbonate regarded as dominant controlling factors. It is considered that carbonate depletion was amplified by freshwater supply inferred by the paleo-position of Spitsbergen in the Greater Barents Sea. Three stages of faunal change were recognised: 1) EPME decline, marked by a δ13Corg negative excursion, monospecific assemblages, significant test size reduction and absence of infaunal components signalling severe hypoxia in middle shelf waters; 2) Initial recovery, with an increase of δ13Corg, paralleled by a low but enhancing species diversity coupled with appearance of infauna suggesting improving oxygenation in outer to middle shelf; 3) Prolonged aftermath, displaying increased but still low diversity signalling persistent restricted conditions, with highly dominant epifauna indicating that oxygen depletion prevailed during the Induan and Smithian stage in middle shelf to lower shoreface settings. The Prolonged aftermath includes a high latitude expression of the Dienerian crisis marked by a δ13Corg excursion with reduction in diversity and infauna.

Keywords: Species diversity, Morphogroups, Size reduction, Hypoxia, Carbonate depletion, Sequence Stratigraphy