Eocene-Oligocene benthic foraminiferal biofacies and depositional sequences at the ACGS 4 borehole, New Jersey Coastal Plain

Previous studies of the Eocene-lowermost Oligocene section at the ACGS 4 borehole recognized physical surfaces using litho- and gamma log- stratigraphy and inferred hiatuses using bio-, magneto-, and isotopic stratigraphy. This study integrates Eocene to Oligocene benthic foraminiferal studies with previous work, identifies additional paraconformities, and places benthic foraminiferal changes into a sequence stratigraphic framework. Although the ACGS 4 borehole provides a reasonably continuous Eocene to lowermost Oligocene shallow-water record integrated stratigraphic studies (sequence, litho-, bio-, isotopic and magneto-stratigraphy) including benthic foraminifera document that deposition was punctuated by at least 6 hiatuses. The hiatuses are associated with unconformities that bracket 7 sequences. Major biofacies and paleobathymetric changes are associated with most of the unconformities that define the bases of the sequences. The unconformities at the ACGS 4 borehole correlate or are consistent with major sequence boundaries of Haq et al. (1987). -from Authors