Seismic stratigraphic and geohistory analysis of Tertiary strata from the continental shelf off New Jersey; Calculation of eustatic fluctuations from stratigraphic data

Abstract

Observations of geologically synchronous basinward shifts in coastal onlap patterns on seismic reflection profiles, from varied tectonic settings and in widespread areas, led Vail and others (1977) to suggest the use of these shifts as a means of global correlation. Sea-level curves based on the interpretation of strati- graphic data are being rigorously tested on the eastern U.S. Continental Margin. The availability of outcrop, well, and seismic data in this region, as well as the general lack of structural overprint over much of the margin, has resulted in its being a focus of research on the effects of sea-level fluctuations on the sedimentary development of basins. Here we present the results of a study in which we apply seismic stratigraphic and geohistory analysis techniques to data from the Baltimore Canyon trough to interpret sea-level changes during the Tertiary. We first develop a stratigraphic framework for the study area through the interpretation of a regional grid of seismic reflection data tied to available well control. We then use the ages of the major depositional sequence boundaries at the COST B-2 well site to predict the thermotectonic subsidence of the basin since the Early Jurassic and to estimate long-term sea- level changes. Finally, we analyze the Tertiary sedimentary patterns expressed in seismic and well data to derive a detailed curve of eustatic changes of sea level.