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ABSTRACT We map the spatial and temporal distribution and depositional environments of Eocene sequences and formations in the New Jersey Coastal Plain, USA, using an array of coreholes and gamma logs. On this passive margin, Eocene depositional systems reflect a change from prograding earliest Eocene mud lobes, to early to middle Eocene hemipelagic ramp, and finally to late middle Eocene prograding sandy sequences. The Marlboro Clay, containing the Paleocene–Eocene Thermal Maximum (PETM), was deposited as prograding fluid mud during times of high global temperatures; it is found in northern and southern lobes but is absent from the central coastal plain. Lower and lower middle Eocene sediments consist of carbonate-rich clays (“marls”) deposited in middle to outer neritic (50–150 m) paleodepths on a hemipelagic ramp during a peak in global mean sea level. Exceptionally deep early Eocene deep water depths compared to other regions are attributed to mantle dynamic topography. The upper middle to upper Eocene consists of three prograding lithologic units found in parallel belts with coarse-grained sediments in the most updip positions and fine-grained sediments found in the most downdip positions; the lithologic units transgress time and sequences. Comparison of the timing of sea-level falls constructed using oxygen isotopes with New Jersey Eocene sequence boundaries shows a correlation between sequences boundaries and global mean sea-level falls controlled by ice-volume changes, even in the purportedly ice-free early Eocene. We date the change from ramp to prograding sequences to the late middle Eocene (ca. 41.5 Ma). We use a forward stratigraphic model to evaluate the primary controls influencing changing styles of sedimentation on the Eocene New Jersey margin. Our forward stratigraphic model shows that the appearance of prograding sands and silts in the middle Eocene is a response primarily to changes in siliciclastic input, presumably due to climate or tectonics in the hinterland. Our study of the New Jersey Eocene shows that by integrating stratigraphic and chronostratigraphic data with an independent estimate of global mean geocentric sea level, our forward model was able to disentangle the effects of sea level and sediment supply on the stratigraphic record. 

We review scientific ocean drilling of the New Jersey passive continental margin and the success of Integrated Ocean Drilling Program (IODP1) Expedition 313 in addressing long-standing, fundamental issues of sequence stratigraphy, sea-level change, and resources. The New Jersey margin was targeted for study by several generations of ocean drilling because of its thick, prograding Oligocene to Quaternary sequences bounded by unconformities. Coring and logging on the onshore coastal plain (Ocean Drilling Program [ODP] Legs 150Xh ttp://www-odp.tamu.edu/publications/citations/cite150X.html and 174AX), outer continental shelf (Leg 174A), and continental slope and rise (Legs 95, 150, and 174A) provided a chronology of sea-level lowerings but did not sample facies needed to evaluate Miocene sea-level amplitudes. Expedition 313 used a Mission Specific Platform (L/B Kayd) to drill on the shallow continental shelf, recover critical Miocene facies, particularly on clinoform foresets, and capture the full amplitudes of relative sea-level changes. Expedition 313 overcame challenging borehole conditions and recovered a total of 1311 m of core at three sites (81 % recovery) that: (1) correlated difficult-to-date nearshore-shelf facies to the time scale with resolution better than ±0.5 million years (Myr); (2) tested and confirmed that sequence boundaries are a primary cause of seismic reflections on siliciclastic shelves; (3) tested sequence stratigraphic models with core-log-seismic integration; and (4) provided a record of paleodepth changes through time that constrained amplitudes of Miocene sea-level change, including the influence of mantle dynamic topography. The New Jersey relative sea-level estimates are similar to those obtained using stable isotopes and Mg/Ca paleothermometry, showing that GMGSL (“eustasy”) varied with 10–60 m scale amplitudes on the Myr scale. Drilling beneath the shallow continental shelf also identified groundwater sources, including seawater, deepsourced brines, and meteoric fresh water, that represent potential resources for future generations. Studies of this margin have implications for future subsurface storage of supercritical CO2 and geotechnical issues relating to the location of offshore wind infrastructure. Expedition 313 demonstrated the feasibility of continuously recovering and logging strata in shallow water, providing constraints on sea level, sequences, hydrogeology, and resources.