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Analysis of Campanian-Lower Maestrichtian benthic foraminiferal assemblages from outcrop and well samples in New Jersey and Delaware has led to recognition of five bathymetric biofacies. Each of the biofacies occurs in adjacent settings to one another in a profile downdip toward the Atlantic basin (paleoslope).
The Gavelinella nelsoni-Gavelinella pinquis biofacies occurs in nearshore sand lithofacies, deposited in depths of 30 to 50 m. The Gandryina stephensoni-Nodosariid biofacies occurs downdip from the above biofacies and indicates environments of deposition of approximately 60 to 80 m (midshelf). The Praebulimina-Pseudouvigenina biofacies which occurs adjacent to the Gandryina stephensoni-Nodosariid biofacies, suggests mid-outer shelf depths of approximately 100 to 150 m. The Heterostomella americana-Gyroidinoides globosus biofacies is characteristic of outer-shelf to slope deposition at approximately 200 to 300 m. The Gavelinella ammonoides-Pullenia cretacea biofacies occurs furthest downdip and suggests paleodepths of greater than 300 m in a slope environment.
These biofacies when plotted along a paleoslope profile enhance the accuracy of estimating paleobathymetry. When applied to studies of cycles of sea-level change the paleoslope profile provides constraints on the magnitude of rise and fall of sea level.
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