150X_Initial Reports Supplement

5 The following, who are listed in alphabetic order, are responsible for the given section: SUMMARY The Cape May site was the third borehole drilled as part of the New Jersey coastal plain drilling project (Leg 150X). It focused on middle Miocene to upper Eocene sequences. Recovery was good (75% mean, 85% median), and gamma and neutron logs were obtained to a total depth (TD) of 1500 ft (457 m). This location is the most downdip onshore location in New Jersey, and the Miocene section is the thickest (823 ft; 251 m) of the three Leg 150X boreholes, with numerous shells suitable for Sr-isotopic age measurements. Un-conformities are revealed by erosional surfaces, gamma-ray peaks, lithologic breaks, biofacies shifts, shell beds, indurated zones, and hiatuses determined by Sr-isotopic stratigraphy and biostratigraphy. Good recovery of sands and clays in the top 357 ft (109 m) provide excellent examples of fluvial-estuarine and marginal marine environments , although age control on this section is poor. The top 90 ft (27 m) of the borehole recovered alternating organic-rich clays and shelly sands deposited in an inlet-marsh environment similar to the modern setting. These Pleistocene to Holocene strata are assigned to the Cape May Formation. Clays from 90 to 140 ft (27−43 m) are tentatively assigned to the Cape May Formation (?Pleistocene). The restricted marine diatom flora and benthic foraminiferal fauna indicate a lower estuarine environment. This unit overlies a thick (140−357 ft; 43−109 m) unit of poorly fossiliferous estuarine sands and clays. Based on stratigraphic studies of the nearby Cape May airport borehole , we tentatively correlate this thick section with a Pliocene unit mapped in the Cape May peninsula (Owens et al., 1995). Four middle Miocene sequences representing 258 ft (77 m) were recovered, including the youngest fossiliferous middle Miocene sequence sampled in New Jersey (ca. 11−12 Ma). We are uncertain if this upper unit (the Kirkwood-Cohansey sequence) correlates with the poorly dated Cohansey Formation or older middle Miocene sequences. Three additional middle Miocene sequences were recovered , including the probable equivalent of the Kirkwood 3 sequence of Sugarman et al. Ma sequence requires verification. The thick lower Miocene section (565 ft; 172 m) represents at least five well-developed sequences. The Kirkwood 2a sequence (650−715 ft; 198−218 m) of Sugarman et al. (1993) is thinner than at Atlantic City where it is well dated (ca. 17.0−18.1 Ma). This sequence is a classic coarsening-upward " …