Recent studies of the Santonian-lower Campanian section (Merchantville Formation) in two coreholes (Ancora and Bass River) from the New Jersey coastal plain postulated the existence of concatenated sequences in glauconitic facies (Miller et al. 2004). The lithologic expression of unconformities within the Merchantville glauconitic sediments is obscure and their resolution requires an integrated stratigraphic approach. Here, we present detailed litho-and biostratigraphic analyses of the Merchantville Formation sequences in four New Jersey coastal plain coreholes (Sea Girt, Ancora, Millville, and Bass River). Biofacies analysis reveals four benthic foraminiferal assemblages from inner to middle neritic environments. Correlation of benthic foraminiferal biofacies, percentage of planktonic foraminifera, and lithologic data indicates that paleowater depths varied between 30 and 75m. The correlation of biostratigraphy, benthic foraminiferal biofacies, lithology, and gamma logs delineates unconformities, and identifies three sequences within the Merchantville Formation (MeI, MeII, MeIII). The ages of these sequences have been constrained by calcareous nannoplankton biostratigraphy (MeI: CC16; MeII: CC17-18; MeIII: CC18-19) from 78.8 to 84.5 Ma. The Merchantville I sequence is observed in the Sea Girt and Bass River coreholes. The Merchantville II and III sequences are present throughout the New Jersey coastal plain, and the ages of the Merchantville II and III sequences boundaries are similar to those of North Carolina, and North-Western Europe suggesting an interregional cause of sequences boundaries. Comparison of the New Jersey shallow marine sequences with the deep-sea record from DSDP Site 511 (Falkland Plateau) show that the episodes of sea-level fall in New Jersey are synchronous with δ 18O increases. Our data imply that the Merchantville sequence boundaries may be attributed to ice volume increases and support the contention that global sea-level changes were controlled by ice-volume variations even during the peak warmth of the Cretaceous.
|Original language||English (US)|
|Number of pages||16|
|State||Published - Jul 6 2009|
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