Upper cretaceous dinoflagellate biostratigraphy of the subsurface Atlantic coastal plain of New Jersey and Delaware, U.S.A.

Abstract

The Upper Cretaceous rocks in five New Jersey wells (all conventional cores) can be informally subdivided using dinoflagellates. The seven zones and three subzones are, in ascending strati‐graphic order: the Trithyrodinium suspectum concurrent range zone (Cenomanian); Canningia sp. A abundance zone (latest Cenomanian to earliest Santonian); Chatangiella micracantha concurrent range zone (earliest Santonian to latest Santonian or earliest Campanian); Spinidinium mariae interval zone (latest Santonian or earliest Campanian to late early or early late Campanian); Palaeohystrichophora infusorioides interval range zone and its three subzones ‐ Chatangiella manumii subzone (late early Campanian to early late Campanian), Chatangiella porata subzone (early late Campanian to late late Campanian) and Diconodinium wilsonii subzone (late late Campanian to early Maastrichtian); Chatangiella? robusta interval zone (Maastrichtian) and Deflandrea galeata interval zone (middle or late to latest Maastrichtian to Early Tertiary). This dinoflagellate zonation is correlated with the standard planktonic foraminiferal zonation, thus allowing correlation with the standard European and North American sections. Based upon this integration of dinoflagellate and foraminiferal biostratigraphy, the unconformity separating the Raritan and Magothy formations appears to range from late Turonian through Coniacian. The analyses of two additional wells provide a means of evaluating the areal applicability of this New Jersey dinoflagellate zonation. One, the Delaware 904 well (also a conventional core) makes possible the correlation of Delaware lithostratigraphy with that of New Jersey. The second is the COST B‐2 well, located in the northern Baltimore Canyon Trough due east of Atlantic City. Analysis of selected samples from this well are supportive of a Campanian‐Eocene bounded unconformity as determined from foraminifers.