Dinoflagellate stratigraphy and facies of the late Cretaceous-early Paleogene (K/Pg boundary) interval at the Bass River site New Jersey, ODP 174X

Dinoflagellate stratigraphy and facies of the late Cretaceous-early Paleogene (K/Pg boundary) interval at the Bass River site New Jersey, ODP 174X

by Saeedi, Farnosh, Ph.D., City University of New York, 2006, 202 pages; AAT 3204987

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Abstract (Summary)

The Bass River site in New Jersey was drilled by the Ocean Drilling Program (ODP 174X) in order to recover the Cretaceous/Paleogene (K/Pg) boundary at an onland location that could be correlated with regional ocean basin sections. The Bass River Site is unique in that a spherule layer was recovered at the K/Pg boundary, this representing the greatest distance (approx. 2500 km) discovered onland yet from the asteroid impact crater situated beneath Chicxulub in the Yucatan Peninsula of Mexico. The study of dinoflagellate fossils in this section is very useful because it benefits the stratigraphic studies that were previously done by Richard Olsson and his colleagues on planktonic and benthic foraminifers, paleomagnetics, sequence stratigraphy, isotope geochemistry, and radioisotope numerical dating.

Dinoflagellate evidence for the K/Pg boundary at Bass River correlates well with the evidence presented previously by Habib, et al ., 1996 for sections in Alabama, Georgia and South Carolina. The Bass River boundary is dated precisely by the successive first appearances of Deflandrea galeata, Cyclapophysis monmouthensis , and Palynodinium grallator in the late Maastrichtian and by Senoniasphaera inornata and Damassadinium californicum in the basal Danian. Dinoflagellate species are used also to date the Early/Late Maastrichtian interval, as well as the Danian interval.

Species diversity, as defined by the ratio of species/specimens in each studied sample, supplemented by the relative abundance of reworked palynomorphs, terrigenous organic detritus, and well-preserved (fecal) amorphous debris, is used to interpret the depositional environments adjacent and across the K/Pg boundary. The boundary ties within the Navesink stratigraphic sequence in an interval of regression of the marine neritic facies. Oxygen isotope data were used previously to interpret the interval immediately below the boundary that had formed during a short period of climatic cooling.

This subject is of palynological interest also because of the unique assemblage of dinoflagellates within 20 cm (7.87 inches) below the boundary. This assemblage consists of an overwhelming numerical abundance of specimens in Manumiella/Isabelidinium and very few other species. Moreover, its stratigraphic position is virtually unique because of its global distribution. It occurs throughout Northern and Southern Hemisphere sections. The global Manumiella "spike" correlates precisely with the stratigraphically short positive excursion of δ 18 O isotope in the Bass River section, which suggests that it formed from a mild cooling event.

Indexing (document details)
Advisor: Habib, Daniel
School: City University of New York
School Location: United States -- New York
Keyword(s): Dinoflagellate, Stratigraphy, Facies, Bass River, New Jersey, Cretaceous-Paleogene
Source: DAI-B 67/01, p. 153, Jul 2006
Publication Number: AAT 3204987
ISBN: 9780542510205

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