Chalk Biozone 5 - Florentinia
Age: Earliest Turonian to mid Turonian
Macrofaunal correlation: The M. nodosoides Zone to the middle of the T. lata/C. woollgari Zone.
Definition: The interval between the LAD of Litosphaeridium siphoniphorum to the FAD of Florentinia? torulosa.
Comments: An additional marker for the base of this biozone is the FAD of consistent representatives of Dinogymnium spp. (Foucher, 1979; Costa & Davey, 1992). However, representatives of this unusual genus have been reported from the Lower Cretaceous (Berriasian to Hauterivian) of southern Europe and the Gulf of Mexico (Londeix et al., 1996). The FAD of Heterosphaeridium difficile is present within this biozone, at the base of the T. lata/C. woollgari Zone (Foucher, 1981; Haq et al., 1987; Foucher & Monteil, 1998).
Lithostratigraphical correlation: The upper Holywell Nodular Chalk to the middle New Pit Chalk formations (Southern Province), the Welton Chalk Formation (Northern Province) and the Herring Formation (North Sea).