END-PERMIAN MASS EXTINCTION OF LAGENIDE FORAMINIFERS IN THE SOUTHERN ALPS (NORTHERN ITALY)

Abstract

Abstract The Permian–Triassic boundary, examined at two sections in the Southern Alps, occurs ∼1.0 to 1.5 m above the base of the Tesero Oolite Member of the Werfen Formation in a depositionally continuous sequence of inner neritic carbonates. Lagenide foraminifers from the boundary interval comprise 27 species in 15 genera plus additional unidentified taxa, most of which became extinct during the end-Permian crisis. The only survivors were “Nodosaria” elabugae and unidentified species in Geinitzina and Nodosinelloides, with representatives of the latter two genera being short-term holdovers. The end-Permian lagenide extinction level occurs a few decimeters below the biostratigraphically defined erathem boundary, just above the contact between the Bulla Member of the Bellerophon Formation and the overlying Tesero Oolite Member. Confidence intervals (>96%) for the lagenide extinction at the two sections are 0.03 and 0.04 m thick. Plots of species' stratigraphic abundance versus their last observed occurren...