AAPG Annual Convention and Exhibition

Datapages, Inc.Print this page

Sequence Stratigraphic Interpretations from Benthic Foraminifera: Analyses of an Onshore Borehole site on the New Jersey Continental Shelf, ODP Leg 174AX


We examined benthic foraminiferal assemblages and planktonic foraminiferal abundances in six lower to middle Eocene sequences at Bass River Site (Ocean Drilling Program Leg 174AX) to reconstruct paleowater-depth changes on the New Jersey continental shelf. The Bass River Site (Ocean Drilling Program Leg 174AX) was the fourth borehole drilled as part of the New Jersey Coastal Plain Drilling Project, which began with ODP Leg 150X. Bass River is an ideal setting to study sequence stratigraphy as it is located in the paleo-inner continental shelf of the stable New Jersey passive margin, and, as a result, is sensitive to changes in sea level. Distinct benthic foraminiferal biofacies are identified and interpreted for paleodepth and environmental signal. Some first and last occurrences of dominant species are stratigraphically important (e.g. Cibicidoides pippeni, Cibicidoides eocenus, Globobulimina ovata, Eponides jacksonensis, Siphonina claibornensis) and may indicate changes in water depth and/or environmental conditions. Middle to outer neritic water depths are estimated for much of the early to middle Eocene, with maximum water depths occurring in the early Eocene. We integrate these results with seismic stratigraphy and lithofacies to create a sequence stratigraphic picture of the paleobathymetry of the early to middle Eocene on the NJ continental margin. We compare the relationship among these sequences to the lithostratographic units and sequence boundaries of previously drilled boreholes of the New Jersey Coastal Plain Drilling Project (Island Beach, Atlantic City, Allaire, and ACGS#4).