Monteverde, D. H. et al. (1998): New seismic correlations of onshore NJ boreholes with offshore sequences; verification of ages and speculations on within-sequence facies variations

ODP 150

Monteverde, D. H.
Rutgers University, Department of Geological Sciences, Piscataway, NJ, United States

Miller, K. G.
Lamont-Doherty Earth Observatory, United States

Mountain, G. S.

Buhl, P.

Carbotte, S.

Sheridan, R.

Cramer, B.

Pekar, S. F.

New seismic correlations of onshore NJ boreholes with offshore sequences; verification of ages and speculations on within-sequence facies variations
In: Anonymous, Geological Society of America, 1998 annual meeting
Geological Society of America (GSA), Boulder, CO, United States
Previous studies by the New Jersey coastal plain drilling project (onshore ODP Legs 150X, 174AX) recognized Cenozoic sequences in boreholes by integrating physical evidence of erosion with age and biofacies/lithofacies changes. Similar studies based on seismic geometries recognized Oligocene-recent sequences beneath the continental shelf and traced them to slope boreholes (ODP Leg 150) where they were dated. Sequence ages compare well onshore and offshore and correlate with deep-sea delta (super 18) O increases, indicating glacioeustatic control on sequence development. However, the onshore borehole data required a several kilometer jump to the closest offshore seismic line, which did not permit direct correlation of the two databases.We present new seismic profiles from the innermost New Jersey continental shelf that come within a few hundred meters of completed or planned onshore boreholes, and tie to existing high-quality seismic grids that extend to the continental slope. The data were collected on the R/V Cape Hatteras in May 1998 with the Lamont-Doherty Hi Res MCS system, and provide approximately 5 m vertical resolution of Oligocene to Lower Miocene sequences buried as much as 700 m beneath the seafloor. With one exception, our preliminary results confirm previous correlations of sequence boundaries with seismic surfaces recognized for the Lower Miocene. We now understand that basal Kw1b sequence boundary (20.1 ma) defined onshore, correlates to offshore reflector m5.4 instead of basal Kw1c sequence boundary (19.5 ma) (Miller et al., 1996), consistent with new core-log studies of slope site 904. These new data clearly show Oligocene clinoform rollovers, corroborating the onshore coastal plain litho/biofacies analysis by Pekar et al. (1997). Eocene sequences from coastal plain wells can be directly correlated into the seismic grid. Along strike variations in thickness of Oligocene-Miocene sequences from northeast to southwest result from primary depositional process rather than faulting. The new seismic data resolution permits the division of these sequences into system tracts and implied sedimentological facies.
Coverage:Geographic coordinates:
West:-75.3500East: -72.1700

Stratigraphy; Atlantic Coastal Plain; boreholes; Cenozoic; continental shelf; correlation; deep-sea environment; eustacy; geometry; geophysical methods; geophysical surveys; isotope ratios; isotopes; Leg 150; Leg 174; lithofacies; marine environment; Miocene; Neogene; New Jersey; O-18/O-16; Ocean Drilling Program; Oligocene; oxygen; Paleogene; seismic methods; sequence stratigraphy; stable isotopes; surveys; Tertiary; thickness; United States; variations;