AAPG Bulletin, V. 82 (1998), No. 5A (May 1998 Part A), P. 773-791.

Late Quaternary Sequence Stratigraphy of a Slowly Subsiding Passive Margin, New Jersey Continental Shelf¹

John S. Carey,² R. E. Sheridan,³ and G. M. Ashley³

©Copyright 1998.  The American Association of Petroleum Geologists.  All Rights Reserved

¹Manuscript received June 12, 1996; revised manuscript received May 8, 1997; final acceptance January 15, 1998.
²Department of Oceanography, Old Dominion University, Norfolk, Virginia 23529.
³Department of Geological Sciences, Rutgers, State University of New Jersey, New Brunswick, New Jersey 08903.

We would like to thank the Minerals Management Service for financial support for this research under their sand resources identification program. We wish to express our gratitude to John Wehmiller, Department of Geology, University of Delaware, Newark, Delaware, for the amino acid racemization analyses and help in interpreting the results. We also would like to thank the staff of the U.S. Geological Survey at Woods Hole for their help in obtaining and interpreting the seismic and core data, particularly Nancy Soderberg, C. Wylie Poag, David Twichell, and Robert Oldale. We also appreciate the helpful reviews of the original manuscript provided by Robert Mitchum and John Anderson.

ABSTRACT

High-resolution seismic profiles over a 25,000 km² area off New Jersey illustrate the effects of high-amplitude, high-frequency eustasy on a slowly subsiding (<0.2 mm/yr) passive margin. Analysis of 1600 km of Geopulse™, Uniboom™, Minisparker™ and air-gun profiles reveals four depositional sequences with a maximum total thickness of 100 m at the shelf edge. Correlation of these sequences to biostratigraphic and aminostratigraphic data from drill sites suggests all of these sequences may be post oxygen isotope stage 6 (~140 ka). Sequences I and IV appear to correspond to the major glacial-interglacial sea level changes (~120 m) during oxygen isotope stages 6/5 and 2/1, respectively. Sequences II and III reflect smaller scale sea level fluctuations. All sequence boundaries are interpreted as type 1, and sequences are predominantly composed of transgressive systems tracts (TST) and lowstand systems tracts (LST). Much of the TST was deposited as incised-valley fills; parasequences in the TST commonly are isolated and fragmented. The low subsidence rate and high-frequency (20 k.y.) eustatic oscillations result in extensive erosion and reworking of previously deposited sediments, both by fluvial incision during lowstands and marine erosion during transgressions and highstands. On continental margins where subsidence rates and sediment supply are low relative to rates of eustasy, sequences are thin, fragmented, and difficult to correlate. Local effects, such as shifting river drainage, salt diapir movements, and glacial isostasy, can significantly influence sequence preservation on such margins.