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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 67 (1983)

Issue: 3. (March)

First Page: 527

Last Page: 527

Title: Paleoslope Models of Miocene-Pliocene and Campanian-Lower Maestrichtian Foraminifera of Maryland and New Jersey: ABSTRACT

Author(s): R. K. Olsson, S. Bam, A. J. Melillo, E. Nyong, B. L. Schreiber

Article Type: Meeting abstract


Paleobathymetric or paleoslope models of the distribution of benthic foraminifera have been constructed for strandline to slope environments of deposition for the Campanian-lower Maestrichtian and the Miocene-Pliocene of the coastal plain of Maryland and New Jersey. Samples from outcrops and downdip wells in formations deposited during four cycles of sea level change in the Miocene-Pliocene and four in the Campanian-lower Maestrichtian are the data base from which the models are constructed. Foraminiferal distributions analyzed downdip in a paleoslope direction and vertically in stratigraphic section utilizing Walther's Law provide a rigid measure of the juxtaposition of biofacies and allow integration of biofacies from each sea level cycle into a single paleoslope profil . Distance downdip in the structurally uncomplicated passive margin of the coastal plain, used as a measure of increasing paleodepth, is a constraint on the estimation of bathymetry of each biofacies. The result is a paleoslope model that relates paleodepth to the abundance distribution of benthic species along the profile. This allows a more critical evaluation of the role played by benthic species in the shelf-upper slope environments during Miocene-Pliocene and Campanian-Maestrichtian times.

Miocene-Pliocene species that have maximum development in 0 to 25 m (82 ft) depth include Elphidium gunteri, Buliminella elegantissima, and Nonionella auris. Species characteristically developed in 30 to 50 m (100 to 165 ft) are Cibicides lobatulus, Fursenkoina fusiformis, and Bolivina multicostata. Hanzawaia concentrica, Florilus atlantica, Textularia agglutinans, and Bolivina paula are among several species with maximum abundance in 50 to 100 m (165 to 300 ft). In 100 to 200 m (330 to 660 ft) are peak occurrences of Hanzawaia berthelotti, Spihogenerina spinosa, Cassidulinoides bradyi, Bolivina fragilis, and Stilostomella bradyi. Species with distributions greater than 200 m (660 ft) include Gyroidina regularis, Sigmoilina tenuis, Bulimina spicata, Oridorsalis tener, and Pullenia sal sburyi.

Campanian-lower Maestrichtian species with peak abundances in 10 to 50 m (33 to 165 ft) include Lenticulina pseudosecans, Citharina suturalis, Pullenia americana, and Clavulina clavata. Species abundant in 50 to 100 m (165 to 330 ft) are Gaudryina stephenson, Clavulina trilatera, Gavelinella pinguis, and nodosarids. Maximum occurrences of Praebulimina carseyae, Coryphostoma plaitum, Loxostomum eleyi, Globorotalites micheliniana, and Gavelinella spissocostata are identified with 100 to 200 m (330 to 660 ft). Heterostomella americana, Osangularia cordierana, Stensioina exculpta gracilis, Pullenia cretacea, and Gavelinella ammonoides are indicative of depths greater than 200 m (660 ft).

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