Trace fossils from the Lower Cambrian Bastion Formation of North-East Greenland

Abstract

New trace fossil collections are described from Lower Cambrian siliciclastic shallow marine shelf deposits of the Bastion Formation of North-East Greenland, together with a taxonomic re-assessment of previously reported material. The entire assemblage comprises 19 ichnogenera, 25 ichnospecies, as well as two vernacular ichnotaxa. Although no new ichnotaxa are present the material reveals new information on the 3-dimensional structure of two of the contained ichnogenera, namely Plagiogmus Roedel and Psammichnites TorelI. The stratigraphic range of a single ichnospecies, Rusophycus latus Webby, is formally extended from the Lower Ordovician to the Lower Cambrian. The assemblage compares favourably with Lower Cambrian ichnocoenoses described from other continents, particularly at the ichnogeneric level. Comparison with similar sequences suggests that the sub-trilobitic Lower Bastion Formation is late Tommotian to early Atdabanian in age, possibly entirely Atdabanian.