The record of Halimedides in the Asturian Basin (northern Spain): supporting the T-OAE relationship

Recent ichnological analysis conducted in two sections (Rodiles and Lastres) of the Asturian Basin revealed the presence of Halimedides Lorenz von Liburnau 1902, which occurs just above the black shales related to the end of the T-OAE. Halimedides is associated with the recovery of the tracemaker community after the reestablishment of favourable, oxic, conditions. The appearance of Halimedides after the T-OAE event, previously not registered, supports the close relationship of the tracemaker with oxygen conditions, as occurs in other anoxic events including the Cretaceous OAE-1a and OAE-2. Also a relation between morphometric and paleoenvironmental parameters is observed, occurring larger and densely chambered specimens in darker, weakly oxygenated facies, while smaller and sparsely chambered forms are registered in lighter, better oxygenated sediments.