Abstract
A new method developed for estimating water depths of benthic foraminifers was implemented for Oligocene foraminiferal bio- facies from the New Jersey Coastal Plain. We combined benthic fo- raminiferal biofacies and two-dimensional flexural backstripping to construct a two-dimensional paleoslope model. The original deposi- tional geometry of New Jersey Oligocene strata was reconstructed by calculating the effects of sediment accumulation and flexural loading. Paleodepth estimates for benthic foraminiferal biofacies were calibrat- ed to inner neritic facies along the resulting nonlinear profile (e.g., with clinoforms). Paleodepth estimates for ten foraminiferal biofacies ranged from 20 6 10 mt o 1156 30 m and were consistent with more qualitative estimates based on other methods (e.g., foraminiferal abun- dances and species diversity). Applying this method to the New Jersey coastal plain for the Oli- gocene showed clear distributional patterns of benthic foraminiferal biofacies. This enabled paleobathymetry to be determined for the re- constructed New Jersey margin as well as significant stratal surfaces within sequences (i.e., systems tracts and condensed sections). Paleo- depth estimates ranged from nearshore (20 6 10 m) up to 85 6 25 m for deposits landward of the clinoform rollover of the underlying se- quence boundary and from middle neritic to outer neritic (50 6 20 m to over 100 6 30 m) on the slopes of the clinoforms. During earliest transgressive systems tracts, paleodepths immediate- ly seaward of the clinoform slope ranged from inner neritic (, 40 m) at updip sites to outer neritic (. 100 m) at downdip sites. During early highstands, paleobathymetry ranged from 45 6 10 to 85 6 25 m land- ward of the clinoform rollover to 85 6 25 m to over 100 6 30 mo n the slope (seaward of the developing prograding sedimentary wedge), while during late HSTs, paleodepths shoaled to as shallow as 25 6 10 m near the clinoform rollover. This method can be applied to other continental passive margins to reconstruct the stratal geometry of and estimate water depths on the shelf. Furthermore, by extending this process, relative sea level and eustatic timings and amplitudes could be evaluated.

This publication has 0 references indexed in Scilit: