IODP Expedition 313 continuously cored uppermost Eocene to lower middle Miocene sequences at three sites (M27, M28, and M29) on the inner-middle continental shelf offshore New Jersey, providing an opportunity to evaluate the ages, global correlations, and significance of sequence boundaries. We dated uppermost Eocene to middle Miocene sequences in the coreholes using integrated biostratigraphy (primarily calcareous nannoplankton, diatoms, and dinocysts) and strontium isotopic stratigraphy. Age resolution is typically ±0.5 Myr and often is as good as ±0.25 Myr. Three Oligocene sequences were sampled at Site M27 on sequence toesets. Fifteen lower to lower middle Miocene sequences were dated at Site M27, M28, and M29 across clinothems in topsets, foresets (where the sequences are thickest), and toesets. A few sequences have coarse (~1 Myr) or little age constraint due to barren zones; we constrain the ages by applying the principle of superposition, specifically that sediments above sequence boundaries in any site are younger than the sediments below the sequence boundaries at other sites. Our age control provides constraints on the timing of deposition in the clinothem: sequences on the topsets are generally the youngest in the clinothem, whereas the toeset strata generally are the oldest. The greatest amount of time is represented on foresets, though we have no evidence for a correlative conformity. Our chronology provides a baseline for regional and interregional correlations and sea-level reconstructions. For example, the timing of sequence boundaries matches the deep sea oxygen isotopic record implicating glacioeustatic lowering change as a major driver for forming sequence boundaries. We correlate offshore sequences with onshore New Jersey Oligocene to Miocene sequences (ODP Legs 150X and 174AX).
Discipline Categories: StratigraphyPreferred Presentation Type: Oral