Scratch circles from the Ediacaran and Cambrian of Arctic Norway and the Republic of South Africa, with a review of scratch circle ocurrences

Abstract

Scratch circles - bedding plane parallel sedimentary structures formed by the passive rotation of a tethered organism into the surrounding sediment - are relatively rare in the geological record. Here new occurrences of scratch circles are described from the Ediacaran-Cambrian Stáhpogieddi Formation, Digermulen Peninsula, Arctic Norway, and from the Ediacaran Nudaus and Urusis formations, Nama Group, of southern Africa. A literature survey confirms a previously noted concentration of scratch circles reported from shallow marine upper Ediacaran-lower Cambrian and paralic Carboniferous rocks. Scratch circle identification and nomenclature are discussed. The stratigraphical range of the trace fossils <i>Treptichnus pedum</i> and <i>Gyrolithes</i> isp. in the Stáhpogieddi Formation are extended downward. Combined with earlier reports of <i>Harlaniella podolica</i> this adds new precision to the placement of the Ediacaran-Cambrian boundary on the Digermulen Peninsula.