Sea-Level Estimates for the Latest 100 Million Years: One-Dimensional Backstripping of Onshore New Jersey Boreholes

Michelle A. Kominz, William A. Van Sickel: Western Michigan University, Kalamazoo MI; Kenneth G. Miller and James V. Browning, Rutgers: The State University of New Jersey, Piscataway, NJ

Abstract

Backstripping analysis of the Bass River and Ancora boreholes from the New Jersey Coastal Plain (Ocean Drilling Project Leg 174AX) provides new Late Cretaceous sea-level estimates and tests previously published Cenozoic sea-level estimates. Amplitudes calculated from all New Jersey boreholes are based on new porosity-depth relationships estimated from New Jersey Coastal Plain electric logs. Amplitudes and duration of sea level are comparable when sequences are represented at multiple borehole sites, suggesting that the resultant curves are an approximation of regional sea level. Sea-level amplitudes as great as 50 m are required by third-order Cretaceous sequences. Most amplitudes are probably closer to 20 to 40 m. Third-order (0.5 - 3 m.y.) sea-level changes of Paleocene and younger sequences are generally less than 30 m and are superimposed on a long-term (= 100 m.y. duration) sea-level fall from a maximum early Eocene value of approximately 100 to 140 m.