Chalk Biozone 18 - Palynodinium grallator

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Age: Late Maastrichtian.

Macrofaunal correlation: The upper B. junior Zone to the B. casimirovensis Zone.

Definition: The interval between the LAD of Triblastula utinensis to the LAD of Palynodinium grallator.

Comments: Alternative indices for the top of this biozone are the LAD of Wilsonisphaera petila (see Schiøler & Wilson, 1994; 1995) and the FADs of Carpatella cornuta, Damassadinium californicum, Dinogymnium spp., Fibradinium annetorpense and Hafniasphaera hyalospinosa (see Hansen, 1977; Foucher & Masure, 1983; Costa & Davey, 1992; Powell, 1992). Glaphyrocysta perforata, Hystrichostrogylon borisii and the zonal index Palynodinium grallator have FADs close to the base of the B. casimirovensis Zone (e.g. Schiøler & Wilson, 1993; Schiøler et al., 1997) hence these datums can significantly subdivide this biozone. Isabelidinium cooksoniae has a useful range top in the late Maastrichtian (Costa & Davey, 1992; Schiøler & Wilson, 1993; Schiøler et al., 1997). Furthermore, the FADs of Senoniasphaera inornata and Thalassiphora pelagica occur in the uppermost B. casimirovensis Zone (Wilson, 1974; Hansen, 1977; Schiøler & Wilson, 1993; Schiøler et al., 1997) and therefore are reliable markers for the uppermost Maastrichtian. The index species, Palynodinium grallator is present, in low proportions, the Danian of Alabama (Habib et al., 1996), however this material may represent reworking.

Lithostratigraphical correlation: The Tor Formation (North Sea).