Updated stratigraphic framework and biota of the Ediacaran and Terreneuvian in the Alcudia-Toledo Mountains of the Central Iberian Zone, Spain

An updated stratigraphic subdivision of the Ediacaran and Terreneuvian in the Alcudia valley and the Toledo Mountains, Central Iberian Zone, is documented here. The Lower Alcudian-Domo Extremeño Supergroup is subdivided, from bottom to top, into the conformable Guadiana (La Coronada and Sta. Mª de Zújar formations) and Campanario (Botija, Monroy and Orellana formations) groups. The supergroup contains biostratigraphically non-significant bacterial acritarchs and dubious fossils, but its Ediacaran age is constrained by detrital zircon analyses. This siliciclastic sedimentary package is unconformably overlain by either the siliciclastic-carbonate Ibor Group (Castañar, Villarta and Arrocampo formations) or the siliciclastic Cíjara Formation. The fossil content of the former group includes Sabelliditids, Vendotaenids, macrophytes, bioaccumulations and reefs rich in Cloudina, Sinotubulites, Protolagena and stromatolites and thrombolites, and a wide diversity of ichnofossils; whereas the Cíjara Formation has yielded bacteria attributed to Bavlinella and Palaeogomphosphaeria, and simple trace fossils (Gordia, Helminthoidichnites and treptichnids). The Ediacaran-Cambrian boundary, based on ichnofossils, lies at the base of the Arrocampo Formation and the uppermost part of the Cíjara Formation. In the Alcudia valley, the Ibor Group is subdivided into another three-fold, lithologically equivalent subdivision, known as the Tamujar, Hinojosas (rich in ichnofossils, such as treptichnids, Monomorphichnus, Psammichnites and Taphrelminthopsis) and Cabezarrubias (including Bergaueria and Planolites) formations. Another unconformity, intra-Fortunian in age, marks the tops of the Ibor Group and the Cíjara Formation, wich are subsequently overlain by the San Lorenzo Formation and some megabreccia beds, respectively. Overlying the slope-related Fuentes, Membrillar and Navalpino megrabreccia beds, the Terreneuvian-Cambrian Series 2, heterolithic Pusa Formation is subdivided into thre members, the middle one characterized by the record of phosphate ore deposits (e.g., the Fontanarejo Bed). The formation is shale dominated and has yielded the body-fossil Beltanelliformis and numerous ichnofossils (Monomorphicnus and Treptichnus; lower member), sponge spicules associated with thrombolites (middle member), and Scenella, trilobites, archaeocyaths and ichnofossils (Dactyloidites, Psammichnites, Rusophycus and Teichichnus; upper member). Where the megabreccia beds are absent, the Ibor Group is unconformably overlain by the San Lorenzo and Fuentepizarra formations, the latter containing phosphatic limestone interbeds rich in skeletonized microfossils, such as Anabarella, which represents the Fortunian-Cambrian Stage 2 boundary interval.