ABSTRACT: Microfossil Evidence of Sea Level Change on the New Jersey Margin: Sequence Biostratigraphic Interpretations

Tiffin, Sarah H., Hopkins, Jennifer A., McCarthy, Francine M.G., and Gostlin, Kevin E., Brock University, St. Catharines, ON, Canada

There is a clear link between sea level fluctuations and the organic productivity of neritic marine environments. These fluctuations exert primary control on sediment distribution patterns along passive continental margins. Sea level changes are also thought to control hydrographic-climatic patterns and biotic distribution patterns. Therefore, study of these fluctuations is of great interest to hydrocarbon exploration. Although stratigraphers have long recognized the importance of transgressive and regressive cycles to the formation of sequence boundaries, these cycle concepts have been difficult to translate into sequence stratigraphic terms. Evidence of subaerial exposure at sequence boundaries can be cryptic. Microfossils are valuable tools in distinguishing between sequence boundaries formed during lowstands and seismic reflectors resulting from other processes. Assuming sea level change as the control on sequence architecture, a model has been constructed to predict microfossil distribution patterns based on taphonomic and paleoecological parameters. A connection can be made between faunal patterns and sequence architecture whereby sequence stratigraphic interpretations are made based on first and last occurrences of index fossils. The New Jersey Margin is an ideal location for testing the microfossil distribution model as this passive margin has been extensively studied in a sequence stratigraphic manner focusing on sea level change. We have a punctuated 20 million year record of microfossil data which we have compared with the seismic stratigraphic record. By recognizing the controls on the stratigraphic distribution of microfossils we can interpret the genesis of sequence boundaries. Understanding the implications of sea level change is of considerable value in deciphering paleoceanographic conditions.

Search and Discovery Article #90907©2000 AAPG Eastern Section Meeting, London, Ontario, Canada