Kai-Uwe Graefe¹
(1) University of Bremen, D-28334 Bremen, Germany

Abstract: Foraminiferal evidence for sequence stratigraphy and paleoceanography of W-European Cenomanian-Turonian hemipelagic sediments

More than 80 Cenomanian to Turonian sections in the Lower Saxony Basin (N-Germany), the London-Paris Basin (N-France), the Aquitaine Basin (S-France), the Basco-Cantabrian Basin (N-Spain), and in the W-Tethys were correlated by means of graphic correlation. A composite standard (CS) with about 230 first and last appearances of planktic foraminifers, large benthic foraminifers, ammonites, and inoceramids was used as chronostratigraphic standard. This CS allows correlation with a resolution better than 100 k.y. between Boreal and Tethyan basins.

Sequence boundaries and maximum flooding surfaces correlated with ammonite or planktic foraminiferal biozones show a good correlation in W-European basins. The same sequence stratigraphic surfaces were also correlated by means of the CS. Then there are mismatches of about 1/4 to 1/2 of one depositional sequence cycle.

The quantitative distribution of planktic and benthic foraminifers reveal little correlation with the sequence stratigraphic subdivision in chalk-dominated sections (London-Paris Basin). Multivariate statistic analysis shows that productivity governs the composition of microfaunas there, and relative sea-level changes are of minor importance.

In basins with stronger input of sediments from emerged areas, paleoceanographic factors are of minor importance. The frequency distribution of benthic foraminifers exhibits strong correlation for nearly all groups to systems tracts and depositional sequences in such settings. The total amount of planktic foraminifers per gram sediment is highest at the maximum flooding surfaces and lowest around sequence boundaries.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana