Foraminifera from the Lower Cretaceous and Upper Jurassic of the Northwestern Atlantic

Abstract

Introduction During Leg 11 (Miami-Hoboken) of the Deep Sea Drilling Project, deposits of early Cretaceous and late Jurassic age were penetrated at four sites. Three of them (Sites 99, 100, 101) are situated in the Blake- Bahama Abyssal Plain to the north and east of San Salvador (Bahama Islands), whereas Site 105 is near northern end of the Hatteras Abyssal Plain approxi- mately 600 kilometers to the east of Cape Hatteras (Figure 1). For exact locations, lithologic descriptions and other details, reference is made to the individual Site Reports in this volume. Figure 1. Location map. This chapter represents a preliminary note on the foraminifera found in the washed residues; in addition, a few other groups of fossils are taken into considera- tion. The few months available between the end of the cruise and the deadline for the submission of this manuscript did not allow a very detailed study of the, in places, rich and varied foraminiferal faunas. Such a comprehensive work would also exceed the scope of an initial report. In this preliminary note, I intend merely to give a general description of the fossils found in the washed residues (mainly in the form of distribution charts), discuss some aspects of the foraminiferal assemblages, and illustrate a few of the more conspicu- ous forms. In view of the importance of the finding of late Jurassic and early Cretaceous foraminifera during Leg 11, I have started their monographic description, which will give the necessary taxonomic discussions and illustrations. It should be emphasized that the determinations given in this preliminary note are provisional. Many of them will undergo changes and, hopefully, some of them will become more precise as work proceeds. A few groups of fossils are discussed in separate chapters in this volume (0. Renz: megafossils, H. J. Oertli: ostracodes, H. Hess: crinoids, and R. Lehmann: thin sections).