4. Oligocene-Miocene Calcareous Nannofossil Biostratigraphy and Paleocology from the Iberia Abyssal Plain1

Eric de Kaenel2 and Giuliana Villa3


During Ocean Drilling Program (ODP) Leg 149, five sites were drilled on the Iberia Abyssal Plain in the northeastern Atlantic Ocean. Both Mesozoic and Cenozoic sediments were recovered. Oligocene to Miocene sediments were cored at deep-water Sites 897, 898, 899, and 900. Except for a few intervals, occurrences of generally abundant and well-preserved calcareous nannofossils suggest that the deposition of the turbidite-type sediments occurred above the calcite compensation depth (CCD). One major unconformity in the middle late Miocene is present.

Detailed quantitative analyses of calcareous nannofossils are used to determine the changes occurring among the nannoflora in relation to sea-level variation. A succession of 89 biohorizons from the early Oligocene to the late Miocene are defined by combining the biostratigraphic results of the four sites studied in the Iberia Abyssal Plain.

One new genus and eight new species are described: Camuralithus, Camuralithus pelliculatus, Ericsonia detecta, Helicosphaera limasera, Sphenolithus akropodus, Sphenolithus aubryae, Sphenolithus cometa, Reticulofenestra circus, and Syracosphaera lamina. Two new variations and seven new combinations are also introduced.

1Examples of how to reference the whole or part of this volume can be found under "Citations" in the preliminary pages of the volume.
2Department of Geology, Florida State University, Tallahassee, FL 32306-3026, U.S.A. dekaenel@geomag.gey.fsu.edu  
3Istituto di Geologia, UniversitÓ degli Studi di Parma Viale delle Scienze 78, 43100 Parma, Italy.

Date of initial receipt: 5 December 1994
Date of acceptance: 25 August 1995
Reproduced online: 21 May 2004
Ms 149SR-208