Abstract: Testing the Relationship of Oligocene to Recent Unconformities, Sequence Boundaries, and Sediment Deposition to Global Sea Level Cycles: Results of the New Jersey Sea Level Transect, ODP Leg 150

John E. Damuth, Gregory S. Mountain, Kenneth G. Miller

Leg 150 drilled a transect of four slope sites (Sites 902-904, 906; 444-1123 m water depths) and one rise site (905; 2698 m) on the New Jersey continental margin to evaluate the effects of global sea level change on deposition of clastic sediments. The primary goal was to date major Oligocene to Recent unconformities (sequence boundaries) to determine their relationship to the glacio-eustatic sea level cycles of the ^dgr¹⁸O record. Additional goals were to determine ages of middle to late Eocene unconformities and to evaluate the relative importance of down-slope vs. parallel-to-slope sediment processes on the continental rise. The slope sites penetrated numerous sequence boundaries that were previously recognized beneath the continental shelf and traced seaward to the slop on a grid of multichannel seismic lines. Stratal surfaces and facies associated with more than 20 of these sequences were recognized and dated in the boreholes. Shipboard age estimates for these sequence boundaries compare favorably with other proxies for sea level change. For example, Pleistocene strata apparently represent a complete record of 4th and 5th order cycles between 474 and 122 ka (^dgr¹⁸O Stages 12 to 5.2) and show that mass-wasting events correlate with times of glacio-eustatic sea level lowerings. Site 906 also documented the history of a buried middle Miocene submarine canyon, whose floor correlates to a major Type I unconformity associated with sea level lowering during a 3rd order sea level cycle at 13.5 Ma. Concurrent with Leg 150, drilling of the updip end of the sequences proceeded onshore at Atlantic City, NJ, where an excellent middle Eocene to Recent section was recovered. These data, plus an uppermost Cretaceous to Recent section recovered onshore at Island Beach, NJ, will compliment the Leg 150 results and should provide firm age constraints on the history of sea level change on this margin.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994