View source for Chalk Biozone 18 - Palynodinium grallator

'''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).

[[Category:Palynological_zonation | 018]]