Late Cambrian acritarchs from the “Túnel Ordovícico del Fabar”, Cantabrian Zone, N Spain

Abstract

A single sample from the La Matosa Member of the Barrios Formation, exposed during the excavation of the El Fabar Tunnel in Asturias, N Spain, yielded a rich and well-preserved Late Cambrian acritarch assemblage. The Middle? to Upper Cambrian La Matosa Member consists mainly of quartz sandstone and includes locally a thick fossiliferous intercalation of dark shale (“El Fabar beds”) from which the acritarch sample was collected. The latter shale levels yielded also some linguliform brachiopods, olenid trilobites and phyllocarid crustaceans.

Characteristic genera of the study sample are Acanthodiacrodium, Lusatia and Cristallinium. Other significant components are Cymatiogalea, Timofeevia and Vulcanisphaera.

Lusatia dendroidea Burmann 1970, recorded for the first time in Spain, is a characteristic element of this assemblage. In the study sample, the latter species is abundant, well-preserved and exhibits appreciable morphological variability.

This acritarch assemblage is correlated with the lower part of microflora RA5 of Parsons and Anderson [Parsons, M.G., Anderson, M.M., 2000. Acritarch microfloral succession from the Late Cambrian and Ordovician (early Tremadoc) of Random Island, eastern Newfoundland, and its comparison to coeval microfloras, particularly those of the East European Platform. AASP Contr. Ser. 38, 129 pp.] corresponding to the Protopeltura praecursor trilobite Zone.