Seven cores were drilled at Site 901 to recover 7.67 m of sediment. Calcareous nannofossils define a discontinuous stratigraphic succession from the upper Pliocene to the Upper Jurassic (lower Tithonian), which is divided into three parts: Cenozoic, Cretaceous, and Upper Jurassic.
The interval from the top of Core 149-901A-1W-1 (lower upper Pliocene) to Sample 149-901A-1W-2, 13 cm (middle Miocene) contains a significant amount of nannofossil ooze with abundant and well-preserved calcareous nannofossils. Sample 149-901A-1W-2,49 cm, is barren of nannofossils but the reddish color of the clay may correspond to the red clay formation of the lithostratigraphic Unit III that was defined at Site 897 and is of middle Eocene to Late Cretaceous in age. Sample 149-901A-1W-2, 55 cm, has the same red brown color and contains very rare Tribrachiatus orthostylus, which indicates an early Eocene age. However, the position of this sample is suspect because of drilling disturbance.Sample 149-901A-1W-2, 50 cm, contains common and moderately preserved nannofossils from the upper Aptian, as indicated by the presence of Eprolithus floralis, Rucinolithus irregularis, Micula infracretacea, Lucianorhabdus carniolensis, Manivitella pemmatoidea, Zeugrhabdotus embergeri, and Watznaueria barnesae. The Lower Cretaceous layers, composed of only 5 mm of gray clay, lie directly below and in conformable contact with the reddish brown claystone, which has been placed in the Cretaceous at Site 899. The Paleocene and probably the earliest Eocene sequences are missing.
No sediment was recovered from Core 149-901A-2R. Cores 149-901A-3R to -7R, which represent 56.50 m, had a recovery of 5.21 m of Upper Jurassic black shales. The presence of black clay and the abundance and highly diversified calcareous nannofossils in some intervals indicate that the deposition took place in a relatively large and deep marine basin (see "Lithostratigraphy" section, this chapter).The interval from Cores 149-901A-3R to -6R has been placed in the Upper Jurassic-early Tithonian stage. Sample 149-901A-3R-1, 1 cm, contains common and moderately well-preserved calcareous nannofossils from the early Tithonian, as indicated by the presence of Stephanolithion bigotii, Conusphaera mexicana minor, Cyclagelosphaera brezae, Faviconus multicolumnatus, Biscutum rotatorium, Watznaueria manivitae, Discorhabdus patulus, Watznaueria fossacincta, Cyclagelosphaera margerelii, Zengrhabdotus erectus, Pichelhaube furtiva, Diazomatholithus lehmanii, Zengrhabdotus fissus, Ethmorhabdus gallicus, Ellipsagelesphaera communis, Markalius ellipticus, Microstaurus quadratus, Polypodorhabdus madingleyensis, Stradnerlithus tortuosus, Ausulosphaera bownii, Zeugrhabdotus noeliae, and Retecapsa catheta.
Sample 149-901A-4W-1, 6 cm, is barren of calcareous nannofossils. Sample 149-901A-4W-1, 31 cm, contains rare and moderately preserved nannofossils. The presence of Stephanolithion bigotii and Conusphaera mexicana minor indicate an early Tithonian age. Sample 149-901A-5R-CC contains few and moderately preserved nannofossils from the middle Tithonian. Sample 149-901A-6R-1, 41 cm, con tains Stephanolithus bigotii, Conusphaera mexicana minor, Ellipsa gelosphaera reinhardtii, Zeugrhabdotus fissus, Axopodorhabdus cylindratus, and Polypodorhabdus madingleyensis. Sample 149-901A-6R-CC contains common and moderately well-preserved nannofossils from the lower Tithonian, as indicated by the presence of Stephanolithion bigotii, Conusphaera mexicana minor, Hexalithus noelia, Ethmorhabdus spp., Cyclagelosphaera margerelii, Zeugrhabdotus erectus, Watznaueria barnesae, and Microstaurus quadratus. Sample 149-901A-7R-CC is barren of calcareous nannofossils.