PALEOWATER DEPTH CHANGE AND DEPOSITION DURING THE LATE SANTONIAN -EARLY CAMPANIAN (77-83.5 MA) ON THE NEW JERSEY COASTAL PLAIN

Evaluation of sequences and paleowater depth fluctuations for Santonian to Campanian sediments (Merchantville Formations) on the New Jersey Coastal Plain constrains the nature and timing of sea level changes. Miller et al. (2004) suggested that very low sedimentation rates in glauconitic facies concatenated sequences. We have carried out a detailed study aimed at delineating concatenated sequences within a single glauconitic section. Integration of Sr isotope and calcareous nannoplankton biostratigraphy with lithofacies and biofacies analyses were used to identify sequences in three ODP Leg 174AX coreholes from New Jersey (Sea Girt, Millville, and Bass River). Biostratigraphy reveals sedimentation rates that are incompatible with continuous sedimentation. On the basis of Sr isotope analysis and nannofossil biostratigraphy we recognize three sequences within the Merchantville Formation (Me1: CC16; Me2: CC17; Me3: CC18-19/20). We constrain the ages of these sequences from 82.5 to 85.2 Ma and estimate the duration of the regional hiatuses. Water depth changes, based on benthic foraminiferal biofacies analysis range from 15 m to 140 m. These sequences are recognized within these three New Jersey coastal plain and at Ancora, NJ (ODP Leg174AX) suggesting that the sequences are regional in extent despite sediment starvation in this interval. Comparison with the deep-sea benthic foraminiferal oxygen isotopic records from Site 511 (Falkland Plateau) imply that the Merchantville sequence boundaries can be linked to the global cooling or ice volume increases. This agrees with the contention that global sea level changes during the peak warmth of the Cretaceous were controlled by ice volume variations.