Mid Cretaceous orbitolinid (Foraminiferida) record from the islands of Cres and Losinj (Croatia) and its regional stratigraphic correlation

The mid Cretaceous shallow-water limestones on the islands of Cres and Losi nj contain abundant and diversified orbitolinid foraminifera. A biostratigr aphy, based on the orbitolinid taxa and their chronostratigraphic interpret ation, is proposed for the Aptian, Albian and Cenomanian deposits in the ar ea investigated. Four orbitolinid biozones have been recognized: (I) Palorb itolina lenticularis Taxon-Range Zone in the Lower Aptian; (2) Orbitolina ( Mesorbitolina) texana Assemblage Zone in the Lower Albian, the body of stra ta being characterized by a distinctive assemblage of Orbitolina (Mesorbito lina) texana, O. (M.) subconcava, O. (M.) parva and O. (M.) pervia; (3) 'Va ldanchella' dercourti Taxon-Range Zone in the basal Upper Albian; and (4) O rbitolina (Conicorbitolina) conica Abundance Zone in the Lower-Middle Cenom anian, a body of strata in which the abundance of the species Orbitolina (C onicorbitolina) conics is significantly greater than is usual in the adjace nt parts of the section, regardless of either association or range. The est ablished biozones on the islands of Cres and Losinj are correlated with orb itolinid biozonations and orbitolinid stratigraphic distributions in the ad jacent areas, with emphasis on the Karst Dinarides. (C) 2000 Academic Press .