HARDENBOL J., Exxon Production Research Co., Houston, TX

ABSTRACT: Sequence Stratigraphic Calibration of Upper Paleocene / Lower Eocene Continental Margin Deposits in Northwestern Europe and The U. S. Gulf Coast with The Oceanic Chronostratigraphic Record

Depositional sequences in the lower Tertiary section of several northwestern European basins in England, Belgium, and France are developed in comparable geologic settings. The interaction of eustasy with low to moderate subsidence and sediment supply in the Upper Paleocene produces a number of incomplete shallow water depositional sequences that onlap Upper Cretaceous chalks of Campanian age. The lower Eocene deeper water London and Yper clay represent a major transgression in which fades changes are subtle and individual sequences are not dearly expressed. Some of the sequences contain enough calcareous nannofossils to establish a tentative correlation with the oceanic continuum.

The Paleocene-Eocene section in the U. S. Gulf Coast in Alabama consists ofcomplete sequences reflecting a faster subsidence and a higher sediment supply. The presence of repeated alternations of lowstand, transgressive and highstand deposits separated by distinct surfaces increases the confidence in the quality of the sequence stratigraphic interpretation. The transgressive deposits are characterized by the occurrence of planktonic foraminifera as well as calcareous nannofossils and thus allow a fairly close correlation with an oceanic chronostratigraphic framework.

Stacking the sequence stratigraphic interpretations from the northwestern European and U. S. Gulf Coast basins within the constraints of all available biostratigraphic and magnetostratigraphic control ensures that fewer sequences escape detection especially in the shallow water deposits of the northwestern European basins. As a result several additional sequences were recognized in the upper Paleocene section of Alabama and the northwestern European basins that were not identified in earlier sequence stratigraphic studies of the respective areas. From the base of the Thanetian Stage, which corresponds approximately to the base of Chron C26 n, to a glauconite level well within the Yper day, indirectly correlated dose to the top of Chron C24 n 1 n, nine sequences have been tentatively i entified.

The major oceanic benthic foraminiferal turnover event, associated with widely recognized shifts in both oxygen and carbon isotopes within Chron 24 r and within planktonic foraminiferal zone P 6 a and calcareous nannofossil zone N P 9, falls below the Eocene-Paleocene boundary as currently defined. The event should approximately correlate with the base of the Woolwich/Reading beds in the U. K., the Sparnacian lignites in the Paris basin and the Greggs Landing Marl within the Middle Tuscahoma Formation in the U. S.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.