1st Research Conference - Gulf Coast Section SEPM

Park formations indicate that the stratigraphic interval containing the
Complexiopollia-Atlantopollis Zone can be assigned to the upper Cenomanian
and lowermost Turonian stages of Europe. The lower part of the Britton
Formation, however, is poorly fossiliferous with respect to pollen. Mollusk and
ostracode data suggest that the Complexiopollia-Atlantopollis Zone should occur
in these beds, which are of middle Cenomanian age. The underlying Tarrant
and Woodbine formations are richly palyniferous and are definitely of pre-
Complexiopollia-Atlantopollis age.
The occurrence of the Complexiopollia-Atlantopollis Zone in the Eagle Ford
Group of Texas not only indicates that the previously suggested correlations of
the Tuscaloosa Group of Alabama with the Woodbine Formation of Texas
should be re-examined, but it allows the establishment of biostratigraphic
relationships between the pollen zone and zones based on other fossil groups.
The lithologic units in which the Complexiopollia-Atlantopollis Zone occurs in
the eastern Gulf and Atlantic coastal plains are typically marginal marine or
nonmarine in origin, and zonal relationships established on the few marine
fossils that do occur in this region are tenuous at best. However, the Eagle
Ford Group of Texas contains a diverse marine invertebrate fauna for which
zonations have been proposed, zonations that can now be related to the
Complexiopollia-Atlantopollis Zone. The core data suggest that the
Complexiopollia-Atlantopollis Zone correlates at least with (1) the entire
Sciponoceras gracile Zone and possibly with the basal part of the Mytiloides
"labiatus" and the upper part of the Ostrea beloiti zones (mollusks), (2) the
upper part of the Rotalia cushmani-greenhornensis Subzone and possibly the
basal part of the Whiteinella archaeocretacea Subzone (foraminifers), and (3)
the Cythereis eaglefordensis and Fossocytheridea lenoirensis range-zones
(ostracodes).