Abstract
Backstripping analysis of three continuously cored, well-dated boreholes from the New Jersey Coastal Plain (Ocean Drilling Program [ODP] Leg 150X) indicates a long-term (108–107 yr) eustatic fall of 
100 m since 55 Ma (early Eocene) and suggests short-term (0.5–3 m.y.) eustatic falls of less than 70 m. Eustatic estimates are calculated from residuals between the decompacted, unloaded, and paleodepth-corrected records and tectonic subsidence (assuming a cooling lithospheric plate). Because the residuals are similar among the three sites, we interpret them as an approximation of the eustatic signal.
Reprinted with permission from the Geological Society of America.
Abstract
Estimates of the magnitudes of changes in third-order (0.5-2 m.y.) eustasy were obtained for Oligocene sequences defined by a suite of largely onshore
boreholes of the New Jersey coastal plain. Benthic foraminiferal biofacies and multiple age constraints in a sequence stratigraphic framework formed the database
for this study. The geometry of the margin through time was determined using two-dimensional backstripping. The depth ranges of benthic foraminiferal biofacies
were determined from a combination of standard factor analysis techniques and the backstripped geometries. Benthic foraminiferal biofacies were then used to
determine the depths of the Oligocene margin profiles obtained from backstripping. The water depths of 16 of these horizons were confirmed by independent
benthic biofacies determinations from at least two wells. This internal consistency indicates that the data and the two-dimensional backstripping approach were
robust. Where benthic biofacies require a vertical shift of the horizons generated by two-dimensional backstripping, eustatic changes were required and were readily
calculated.
Results indicate a major eustatic fall from the end of the Eocene to the first record of Oligocene deposition. Subsequent long-term shoaling of sea level
through the Oligocene was ~30 m in 10 m.y. Superimposed on this long-term trend were higher frequency (third-order) variations in eustasy with amplitudes of ~40 m or less.
Reprinted with permission from the Geological Society of America.
Abstract
We provide a record of global sea-level (eustatic) variations of the Late Cretaceous (99-65 Ma) greenhouse world. Ocean Drilling Program Leg 174AX provided a record of 11-14 Upper Cretaceous sequences in the New Jersey Coastal Plain that were dated by integrating Sr isotopic stratigraphy and biostratigraphy. Backstripping yielded a Late Cretaceous eustatic estimate for these sequences, taking into account sediment loading, compaction, paleowater depth, and basin subsidence. We show that Late Cretaceous sea-level changes were large (>25 m) and rapid (<<1 m.y.), suggesting a glacioeustatic control. Three large 
18O increases are linked to sequence boundaries (others lack sufficient 18O data), consistent with a glacioeustatic cause and with the development of small (<106 km3) ephemeral ice sheets in Antarctica. Our sequence boundaries correlate with sea-level falls recorded by Exxon Production Research and sections from northwest Europe and Russia, indicating a global cause, although the Exxon record differs from backstripped estimates in amplitude and shape.
Reprinted with permission from the Geological Society of America.
Abstract
We developed a Late Cretaceous sea- level estimate from Upper Cretaceous sequences at Bass River and Ancora, New Jersey (ODP [Ocean Drilling Program] Leg 174AX). We dated 11–14 sequences by integrating Sr isotope and biostratigraphy (age resolution ±0.5 m.y.) and then estimated paleoenvironmental changes within the sequences from lithofacies and biofacies analyses. Sequences generally shallow up-section from middle-neritic to inner-neritic paleodepths, as shown by the transition from thin basal glauconite shelf sands (transgressive systems tracts [TST]), to medial-prodelta silty clays (highstand systems tracts [HST]), and finally to upper–delta-front quartz sands (HST). Sea-level estimates obtained by backstripping (accounting for paleodepth variations, sediment loading, compaction, and basin subsidence) indicate that large (>25 m) and rapid (<<1 m.y.) sea-level variations occurred during the Late Cretaceous greenhouse world. The fact that the timing of Upper Cretaceous sequence boundaries in New Jersey is similar to the sea-level lowering records of Exxon Production Research Company (EPR), northwest European sections, and Russian platform outcrops points to a global cause. Because backstripping, seismicity, seismic stratigraphic data, and sediment-distribution patterns all indicate minimal tectonic effects on the New Jersey Coastal Plain, we interpret that we have isolated a eustatic signature. The only known mechanism that can explain such global changes— glacio-eustasy—is consistent with foraminiferal 18O data. Either continental ice sheets paced sea-level changes during the Late Cretaceous, or our understanding of causal mechanisms for global sea-level change is fundamentally flawed. Comparison of our eustatic history with published ice-sheet models and Milankovitch predictions suggests that small (5–10 x 106 km3), ephemeral, and areally restricted Antarctic ice sheets paced the Late Cretaceous global sea-level change. New Jersey and Russian eustatic estimates are typically one-half of the EPR amplitudes, though this difference varies through time, yielding markedly different eustatic curves. We conclude that New Jersey provides the best available estimate for Late Cretaceous sea-level variations.
Reprinted with permission from the Geological Society of America.
Abstract
Previously published Oligocene eustatic records are compared with observed stratigraphic architecture at the New Jersey continental margin in order to
evaluate the stratigraphic response to eustatic change. Lower to mid-Oligocene sequence boundaries (33.8-28.0 Ma) are associated with relatively long
hiatuses (0.3-0.6 m.y.), in which sedimentation in many places terminated during eustatic falls and resumed early during eustatic rises. Upper Oligocene
sequence boundaries are associated with relatively short hiatuses (<0.3 m.y.), and provide the best constraints on phase relations between sea-level forcing and
margin response. The interval represented by each upper Oligocene sequence varies in dip profile. At updip locations, landward of the clinoform rollover in the
underlying sequence boundary, sedimentation commenced after the eustatic low and terminated before the eustatic high (with partial erosion of any younger
record). At downdip locations, sedimentation within each sequence was progressively delayed in a seaward direction, beginning during the eustatic rise and
terminating near the eustatic low. Combining data from all available boreholes, ages of sequence boundaries (correlative surfaces) correspond closely with the
timing of eustatic lows, and ages of condensed sections (intervals of sediment starvation) correspond with eustatic highs.
Reprinted with permission from the Geological Society of America.
Abstract
Nine latest Eocene to Oligocene (34.2-23.9 Ma) sequences were identified and dated from eight sites situated on the onshore New Jersey Coastal Plain
and nearshore region. These sequences show a patchy distribution, with more complete lower Oligocene sections updip and more complete upper
Oligocene sections downdip. We projected these sequences onto a dip profile and reconstructed their original thicknesses and distributions by 2-D
flexural backstripping. This demonstrated that depocenters migrated offshore during the Oligocene, indicating that the patchy distribution can be best
explained by progradation of generally thin and spacially limited clinoforms over an Eocene carbonate ramp. During the late Eocene to Oligocene, the New
Jersey passive margin underwent a major morphologic change. Reconstructions indicate that the margin was a relatively steeply dipping carbonate ramp
(1:500 paleoslope gradient) during the Eocene and was transformed into a siliciclastic margin characterized by a gentler gradient of 1:1000 and prograding
clinoforms by the Miocene. Clinoform progradation probably began during the latest Eocene. Increased sediment supply during the Oligocene resulted in
the further progradation of sediments across the antecedent carbonate ramp. The heights of the clinoforms ranged from ~20 m during the latest Eocene and
earliest Oligocene to nearly 50 m during the late Oligocene. Most sediment accumulated within clinoform wedges, with little or no sediment being
preserved behind the clinoform inflection point.
Reprinted with permission from Elsevier Science and ScienceDirect.
Abstract
We have reconstructed the Oligocene to Middle Miocene paleobathymetry and stratigraphy of the New Jersey margin using a modified backstripping
technique. By analyzing the geometry of the margin through time, we investigate its response to fluctuating sea level, changing climate, and variable
sediment supply during the Tertiary. The reconstructions reveal a change in the margin morphology from a more steeply dipping (1 : 300 to 1 : 500)
carbonate ramp in the Eocene to a flatter shelf with a sharp shelf edge at present. This was accomplished by an increase in the terrigenous sediment supply
that filled available accommodation and caused progradation across the margin. We link the increase in sediment flux with climatic cooling rather than
tectonic processes. The progradation is evidenced by a series of clinoforms whose formation was modulated by sea level and which extend over 100 km
across the shelf. The height and dip of the clinoforms increased as they extended onto the deeper parts of the earlier ramp. The Miocene clinoform
rollovers at the New Jersey margin had water depths of ~60-130 m and are interpreted as the edge of a new continental shelf built over the older ramp.
Sea-level fall was probably insufficient to drive the Miocene shorelines past the shelf breaks. Thus, measurements of sea-level amplitude based upon
`coastal' onlap over the clinoforms are not reliable.
Reprinted with permission from Elsevier Science and ScienceDirect.