39. HIGH-RESOLUTION PLIOCENE–PLEISTOCENE BIOSTRATIGRAPHY OF SITE 959, EASTERN EQUATORIAL ATLANTIC OCEAN1

Im Chul Shin,2,3 Samir Shafik,4 and David K. Watkins2

ABSTRACT

High-resolution calcareous nannofossil biostratigraphy was examined from Cores 159-959C-1H through 8H in 20-cm intervals for the Ocean Drilling Program in the eastern equatorial Atlantic Ocean. Well-preserved marker species occur continuously and are relatively abundant in Hole 959C. Six zones (CN10 through CN15) are identified. All calcareous nannofossils are well preserved. Late Neogene (Pliocene–Pleistocene) sediment is dominated by Florisphaera profunda, Gephyrocapsa caribbeanica, G. oceanica, Gephyrocapsa spp., Reticulofenestra pseudoumbilica, R. minutula, and small Reticulofenestra. The sedimentation rate varies from 0.4 cm/k.y. to 13.5 cm/k.y. This strong variations are related to disconformities. The lowest sedimentation rate occurs in the early late Pliocene (Subzone CN12a; 0.4 cm/k.y.), and the highest sedimentation rate in the early early Pleistocene (Subzone CN13b; 13.5 cm/k.y.). The average sedimentation rate from Cores 159-959C-1H through 8H is 1.5 cm/k.y.

1Mascle, J., Lohmann, G.P., and Moullade, M. (Eds.), 1998. Proc. ODP, Sci. Results, 159: College Station, TX (Ocean Drilling Program).
2Department of Geology, University of Nebraska-Lincoln, Lincoln, NE 68588-0340, U.S.A.
3Korea Ocean Research and Development Institute, Ansan, P.O. Box 29, Seoul 425-600, Korea. icshin@sari.kordi.re.kr
4Australian Geological Survey Organization, Marine, Petroleum and Sedimentary Resources, GPO Box 378, Canberra City, ACT 2601, Australia.