Integrated sequence stratigraphy of Neogene deposits, New Jersey continental shelf and slope: Comparison with the Exxon model

Abstract

We have evaluated the Neogene stratigraphic succession beneath the continental shelf off New Jersey using high-quality seismic and well data to (1) construct geologic cross sections that relate seismic geometries to lithofacies in a prograding, tectonically quiescent setting; (2) apply a sequence-stratigraphic approach to subdivide the stratigraphic section and relate the characteristics of the deposition observed sequences to the published Exxon model; and (3) determine the resolution of the available biostratigraphy in the correlation of the offshore New Jersey depositional sequences to the published eustatic cycle chart. In the offshore New Jersey area, the well-developed progradational geometries in the Neogene section, the high-quality seismic data, and the relatively abundant lithologic information from wells allow us to use the results of this study to predict lithofacies distribution in similar, but less geologically constrained, settings. Depositional sequences are characterized by similar overall stacking patterns within component systems tracts; however, the New Jersey sequences are different in several ways. These differences include the lack of type-2 unconformities, an absence of leveed channel deposits within lowstand wedges, very poorly developed transgressive systems tracts, and sandstone-rich, high regressive highstand systems tracts. These differences are explained in terms of the limited Neogene accommodation on the Newmore » Jersey shelf that resulted from slow subsidence rates and a second-order Miocene eustatic fall. Paleontologic data bracket the ages of the individual sequences but are not detailed enough at present to correlate precisely to the time scale and inferred global sea-level records. Based on the available biostratigraphy, however, Neogene depositional sequences from offshore New Jersey have a cyclicity consistent with interpreted third-order eustatic fluctuations on the global cycle chart. 18 refs., 6 figs., 1 tab.« less