Integrated stratigraphic studies of Paleocene-lowermost Eocene sequences, New Jersey Coastal Plain: Evidence for glacioeustatic control

Abstract

[1] We describe seven Paleocene to lowermost Eocene sequences in core holes at Island Beach, Bass River, Ancora, Millville, and Sea Girt, NJ (Ocean Drilling Program Leg 150X, 174AX) and analyze benthic foraminiferal assemblages to assess paleodepth changes within sequences. These sequences are referred to as Pa0, Pa1a, Pa1b, Pa2a, Pa2b, Pa3a, and Pa3b. Paleocene sequence boundaries are identified by unconformities and variations in benthic foraminiferal biofacies. We used Q-mode factor analysis and paleoslope modeling to identify three distinct middle-outer neritic benthic foraminiferal assemblages and their associated water depths. Paleodepths during the early Paleocene and deposition of Pa0, Pa1a, and Pa2b were ∼80 m with ∼20 m changes across sequence boundaries. A long-term shallowing occurred through the late Paleocene where paleodepths were ∼50-70 m in Pa3a. This trend drastically changes in the earliest Eocene where the paleodepths of sequence Pa3b were ∼120-150 m. New Jersey Paleocene sequence boundaries correlate with those in other regions and with d18 O increases in the deep sea, suggesting Paleocene eustatic lowerings were associated with ice-growth events.

Wilson Lake site

“…The beginning of the PETM is associated with a rapid 2.5‰-7‰ decrease in global bulk δ 13 C values, followed by a subsequent period of low stable δ 13 C values ("the core" of Röhl et al, 2007), and an exponential recovery over ~100-200 ky (e.g., Kennett and Stott, 1991;Bains et al, 1999;Katz et al, 1999;Röhl et al, 2000;Farley and Eltgroth, 2003;Murphy et al, 2010), collectively known as the CIE. The CIE and period of low δ 13 C values has been found associated with the Marlboro Clay throughout New Jersey Zachos et al, 2006;Harris et al, 2010;Makarova et al, 2017) and is especially notable in Wilson Lake Hole A (Sluijs et al, 2007).…”

“…It is assigned to Zone NP9 (uppermost Paleocene) and correlated to Sequence Pa3a of Harris et al (2010). The contact with the underlying Hornerstown Formation (389.8-410.7 ft; 119.57-125.2 m) appears conformable.…”

“…may be sequence Boundary Pa2a of Harris et al (2010), that is placed elsewhere in Zones P4a and NP6. Clayey glauconite sand with brownish gray matrix occurs from 399.6 to 403.55 ft (121.6 to 123.0 m), where there is a contact with clayey glauconite sand with a phosphorescent green clay (vivianite?)…”

“…Below 380 ft (115.8 m), the sandy clayey silt becomes increasingly glauconitic (~20%), more laminated (with 3-4 mm scale laminations), and decreasingly micaceous down to clayey glauconite (~58%) sand at ~389.8 ft (118.8 m). All samples examined are assigned to Zone NP9 (uppermost Paleocene), indicating that this interval can be correlated to Sequence Pa3a of Harris et al (2010). Figure F14).…”

Stable isotope and calcareous nannofossil assemblage record of the late Paleocene and early Eocene (Cicogna section)

“…2), and an overall different environmental setting. Many early Paleogene records, especially those from paleo-shelf environments, such as in Egypt (e.g, Aubry and Salem, 2012) and New Jersey (Mixon and Powars, 1994;Harris et al, 2010), or from early deep sea drilling expeditions, such as in the Indian Ocean (Slotnick et al, 2015b), are discontinuous, because of either hiatuses or core gaps. Much of the detailed work and current understanding of stable carbon isotope stratigraphy and calcareous nannofossil variations across the broad early Paleogene, therefore, has come from deep-sea drilling sites with multiple holes but slow sedimentation rates, although we note the work in Clarence Valley, New Zealand ( Fig.…”