Ichnofacies

Seilacherian or archetypal ichnofacies are conceptual constructs based on the identification of key features shared by different ichnocoenoses of a wide range of ages and formed under a similar set of environmental conditions. Historically, the ichnofacies concept has been central in the transformation of ichnology from a marginal field to a discipline at the core of sedimentary geology, playing a crucial role in facies analysis and sequence stratigraphy. Since its origin focused on marine softground associations, the ichnofacies model has been expanded to accommodate ichnofacies from various types of substrates and continental settings. Invertebrate ichnofacies include three main types: softground marine, substrate-controlled, and continental. Softground marine ichnofacies comprise the Psilonichnus, Skolithos, Cruziana, Zoophycos and Nereites ichnofacies, and have been typically used to establish paleoenvironmental zonations in marine environments, from the backshore to the deep sea. Substrate-controlled ichnofacies consist of the Glossifungites, Trypanites, Gnathichnus, and Teredolites, which are typically used in sequence stratigraphy. Continental archetypal invertebrate ichnofacies comprise the Scoyenia, Mermia, Coprinisphaera, Termitichnus, Celliforma, and Octopodichnus-Entradichnus. Whereas the freshwater ichnofacies are mostly controlled by the position of the water table, paleosol ichnofacies display a close correspondence with plant formations and climate. Despite its common use, there are still common misunderstandings regarding the ichnofacies concept.