Late Albian-Early Cenomanian stratigraphic succession near Estella-Lizarra(Navarra, central northern Spain) and its regional and interregional correlation

The sedimentology, depositional environment and biostratigraphy of the Zufi a Formation (1580 m thick), which crops out around the Estella-Lizarra diap ir in Navarra, is described. The age of this formation is Late Albian to Ea rly Cenomanian and represents the most complete succession of this time int erval known so far in the Basque-Cantabrian region of northern Spain. The s uccession evolves upward from sandstones to marls and calcarenites. The sed imentology indicates deposition in a shallow marine environment extending f rom delta front prograding bars into an offshore region generally below sto rm-wave base. Within it, important non-sequences are present which can be c orrelated with either local or regional changes in sea level and provide a test of current Late Albian and Cenomanian global sea-level change models. Biostratigraphical data from scattered ammonite and good foraminiferal occu rrences date the formation with accurate calibration between benthic, nekto nic and planktonic faunas. The lower part of the succession (880 m) belongs to the Hysteroceras varicosum and Mortoniceras inflatum (sensu stricto) am monite Zones of the Tethyan province. The Stoliczkaia dispar Zone is repres ented by 460 m of sediment of which 210 m belongs to the Mortoniceras (Mort oniceras) rostratum Subzone and 250 m to the Mortoniceras (Durnovarites) pe rinflatum and Arrhaphoceras (Praeschloenbachia) briacensis Subzones, based on ammonite occurrences. On planktonic foraminiferal evidence, the Arrhapho ceras (Praeschloenbachia) briacensis Subzone may be represented by a furthe r 40 m of sediment of latest Albian age which have not yet yielded ammonite s. The uppermost 240 m of the Zufia Formation is of Early Cenomanian date b ased, essentially, on planktonic foraminiferal evidence. The section is sur mounted by 100 m of Middle Cenomanian sediments of the Ollogoyen Formation. Very few ammonites are known from this Cenomanian succession. Biostratigra phically, there is close correlation with the Vocontian Trough of southern France. (C) 1999 Academic Press.