Research-paper
New Early and Middle Eocene calcareous-nannoplankton events and correlations in middle to high latitudes of the northern hemisphere
Steurbaut, Etienne
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Abstract
A new Early and Middle Eocene calcareous-nannoplankton zonation is proposed for middle to high latitudes of the northern hemisphere. Fourteen units are introduced on the basis of worldwide, easily recognizable events. Correlation with MARTINI's standard calcareous-nannoplankton zonation is established: units I, II and IIIa are assignable to zone NP11, units IIIb, IV, V, VI, VII and VIII to NP12, units IX and X to NP13 and units XI, XII, XIII and XIV to NP14. The Belgian Basin contains one of the most complete, most fossiliferous and best outcropping Early and Middle Eocene sequences of Europe, and probably far beyond. The Cuisian is proved to correspond to the lower part of the Ypresian, and thus only represents a brief interval. The base of the Lutetian in the type-area appears to be much younger than in adjacent basins, implying the need to redefine the Lutetian Stage. Some general correlations between the European and North American Tertiary Basins are established. A more sophisticated correlation scheme of both areas cannot yet be proposed, because neither detailed investigations nor very closely spaced sampling of most American basins have been carried out.