PALYNOLOGY OF THE HOOPER FORMATION (PALEOCENE), WILCOX GROUP, BASTROP COUNTY, TEXAS: A PRELIMINARY STUDY

Biostratigraphic and paleoecological studies of Upper Wilcox Group sediments and sedimentary rocks from the Calvert Bluff and Sabinetown formations have been ongoing across central and eastern Texas since the 1960’s, resulting in a large body of information about biotic changes through the upper Paleocene and lower Eocene. Less well known and largely unstudied are onshore sediments and sedimentary rock from the lower Wilcox Group, especially from the “Hooper Formation.” The unofficially designated Hooper Formation denotes a siliciclastic sequence above the Caldwell Knob Oyster Bed and below the Simsboro Sand throughout Central Texas. The type section for this unit is partially exposed in badlands terrain in McKinney Roughs Nature Park on the southwestern side of the Colorado River, adjacent to the Wilbarger Bend in Bastrop County, TX. In one ca. 4 m exposure, sandy tidal heterolithics underlay a single subbituminous coal seam with two splits. Samples through the unit, concentrating on the coal, were obtained in May of 2017. The samples were processed and analyzed for palynology. This preliminary work has shown that the tidal heterolithics contain an abundant and diverse palynoflora, dominated by tree pollen, including members of the chestnut family, walnut family, and palms. The coals contain an abundant, but much less diverse flora, dominated by freshwater algae and fern spores, that includes willow, sedge, and dogwood family pollen. Here we provide an overview of the results of the preliminary study.