PALEOCENE-EOCENE PALYNOLOGY AND STRATIGRAPHIC CORRELATION ACROSS A NEARSHORE-TO-OFFSHORE TRANSITION IN THE SUBSURFACE OF CENTRAL DELAWARE (U.S. MID-ATLANTIC COASTAL PLAIN): A PRELIMINARY STUDY

This study examines the stratigraphy and palynology of three Paleocene-Eocene formations, the Vincentown, Manasquan, and Shark River Formations, in the subsurface of the Coastal Plain of Delaware. This interval includes a unit of glauconite-quartz-shell-rich sands in central Delaware that comprises the regionally important Rancocas/Aquia aquifer. Lithologies change in a short distance (~10 km) southeastward from very permeable clean aquifer sands to much less permeable muddy sands and sandy muds, representing a transition from nearshore, clear, warm-water, carbonate-rich sand shoals to mud-dominated deeper-water, offshore shelfal environments. However, the stratigraphic details of this lithofacies transition are unclear. Of additional interest in this interval is the Paleocene-Eocene Thermal Maximum (PETM) global warming event. Kaolinitic clays of the Marlboro Clay are known to be associated with the PETM in the Middle Atlantic region; however, these kaolinitic clays are so far unknown from this area of the Delaware Coastal Plain. The age and correlations of these formations are evaluated using samples from three boreholes drilled with continuous wireline coring: Blackbird, Smyrna, and Woodland Beach. The study integrates lithologies, fossil palynomorphs, fossil dinoflagellate cysts, and sequence stratigraphy to understand the correlation of strata and hiatuses across the nearshore to offshore transition, as well as to seek evidence of the stratigraphic record of the PETM. Preliminary palynological analysis reveals the presence of generally abundant pollen and dinoflagellates that will shed light on the stratigraphy of this interval. Angiosperm pollen from the stratigraphically useful Momipites-Caryapollenites lineage are present in many of the samples. Dinoflagellates are numerous and diverse in most samples, generally more so in the deeper locations (Smyrna and Woodland Beach), and include numerous taxa typical of previous studies of the Paleocene-Eocene section in the Middle Atlantic Coastal Plain.