Latest Neoproterozoic to Middle Cambrian body fossil record in Spain (exclusive of trilobites and archaeocyaths) and their stratigraphic significance

Abstract

The chronostratigraphical aspects of four Iberian non-trilobite and non-archaeocyathan associations and the record of two separate fossil occurrences are discussed. These fossils are Cloudina and Platysolenites. The associations have been defined as the Anabarella-Aldanella, Arthropoda-Tannuolina-Latouchella, Alanís Fauna, and Hadimopanella-Archiasterella assemblages. They comprise a time span from the late Vendian to the early Middle Cambrian. The existence of upper Vendian associations in the Rio Huso and Ibor groups outcropping through Central Iberia is indicated by the presence of Cloudina. Its biostratigraphic overlapping with vendotaenids and Sabellidites may correlate it with the Sabellidites-Vendotaenia assemblage. In the upper member of the Rio Huso group (Valdelacasa Anticline) and Upper Alcudian strata (Alcudia Valley) the Anabarella-Aldanella association has been found. It may belong to the middle-upper Tommotian in the Siberian Platform and Mongolia and also with the upper Alcudian in Iberia. In the Sierra de Córdoba area, Southern Spain, an Arthropoda-Tannuolina-Latouchella association has been found in the Pedroche Formation, which has been correlated with the late Tommotian to early Atdabanian, based on problematical taxa, archaeocyathid and trilobite stratigraphy. Based on its trilobite associations, a middle Marianian age for the Alanís Fauna and Platysolenites antiquissimus Eichwald, 1860 is established. The youngest association, the Hadimopanella-Archiasterella association, has been found in the lower part of the Láncara Formation of the Cantabrian Ranges. Owing to a diachronism, there are only some localities where the griotte member starts in the Eoparadoxides mureroensis Zone. However, green glauconitic limestones, probably formed during a sedimentary condensation, yield Hadimopanella, so it could appear at the beginning of the Eoparadoxides mureroensis Zone or at the end of the Bilbilian.