During ODP Leg 189, the E-O transition was recovered at Sites 1168 (Hole 1168A), 1170 (Hole 1170D), 1171 (Holes 1171C and 1171D), and 1172 (Holes 1172A and 1172D). As indicated above, the middle Eocene (or older) to Oligocene sedimentary succession is very similar at these sites and is basically divided into three lithostratigraphic units: (1) middle Eocene or older organic-rich brown, green, and gray relatively shallow marine silty mudstones (Site 1170: Unit V and lower Unit IV; Site 1171: Unit IV; and Site 1172: Unit III); (2) a condensed upper Eocene-lowermost Oligocene transitional unit characterized by increased glauconite content (Site 1170: upper Unit IV; Site 1171: Unit III; and Site 1172: Unit II); followed by (3) an increasingly calcareous succession of mainly nannofossil ooze that represents most of the Oligocene and the entire Neogene (Site 1170: Units III-I; Site 1171: Units II-I; and Site 1172: Unit I). Only at Site 1168 is the E-O transitional unit more expanded (see Shipboard Scientific Party, 2001b). Although these units have been recognized at all Leg 189 sites (except at Site 1169, which did not penetrate the Paleogene), they are not identically labeled because of minor local differences. For more details, see the Leg 189 Initial Reports volume (Exon, Kennett, Malone, et al., 2001) and further related studies (Shipboard Scientific Party, 2001a; Stickley et al., submitted [N1]). In addition, sedimentation rates clearly reflect these three distinct phases. During the middle Eocene and older interval, sedimentation rates were relatively high. From the late Eocene through the Oligocene, sedimentation rates dramatically decreased and increased locally thereafter until the present day (Stickley et al., this volume). These three basic intervals coincide with the global climate change succession of states from "Greenhouse" to "Doubthouse" to "Icehouse" as postulated in Shipboard Scientific Party (2001a). The basic units are broadly taken to represent (1) relatively shallow-marine, neritic, siliciclastic, pro-deltaic settings, which are (2) replaced by deeper-marine, current-swept settings, which eventually evolve into (3) deep marine calcareous ooze pelagic settings (Shipboard Scientific Party, 2001a). For discussion purposes we will here refer to these units as the pro-deltaic, transitional, and pelagic units, respectively.
In general, one sample per core section (average spacing = ~1.5 m) from Holes 1170D and 1171D were palynologically analyzed, whereas more closely spaced sampling (~10 cm) was achieved for Hole 1172A (Tables T1, T2, T3).
Most samples were processed for semiquantitative palynological analysis. Absolute abundance data (i.e., number of palynomorphs per gram) have been generated from selected samples (indicated in Tables T1, T2, T3) via standard palynological techniques (involving spiking the samples with exote Lycopodium). All samples were processed at the Laboratory of Palaeobotany and Palynology, Utrecht University, The Netherlands.
Sample processing for absolute concentrations involved ~15 g of wet sediment that was dried at 60°C and weighed. After adding exote Lycopodium, the sample was treated with 30% hydrochloric acid (HCl) and twice with 30% hydrofluoric acid (HF) for carbonate and silicate removal, respectively. After overnight settling and neutralizing with distilled water, the supernatant was decanted. Both HF steps included 2 hr shaking and 20 hr reaction time, decanting, and addition of 30% HCl to remove fluoride gels. The residue was sieved twice using a 10-µm nylon mesh sieve to remove small particles. To break up clumps of residue, the sample was placed in an ultrasonic bath for a maximum of 5 min after the first sieving. A superficial film of residue was removed by reducing the cohesion with dissolved soap. The residue was then centrifuged (5 min; 2400 rpm), transferred to a reaction vessel with a 0.5-mL scale interval, and concentrated to 1 mL. With a micropipette, subsamples of a known volume (10-35 µL) of homogenized residue were placed on a microscope slide, embedded in glycerine jelly, and sealed with paraffin wax (cf. Boessenkool et al., 2001).
The remaining samples were processed using standard techniques. From the core samples ~15 g of wet sediment was collected and oven dried at 60°C and weighed (8-14 g). Processing involved an initial treatment in 10% HCl to dissolve carbonates, followed by a treatment of 38% HF to dissolve silicates. After each acid step, samples were washed twice by decanting after 24 hr settling and filling up with water. The HF step included 2 hr shaking at ~250 rpm and adding 30% HCl to remove fluoride gels. Then, samples were repeatedly washed in distilled water and finally sieved through a 15-µm nylon mesh sieve. To break up clumps of residue, the sample was placed in an ultrasonic bath for a maximum of 5 min after the first sieving. The residue remaining on the sieve was transferred to a glass tube. The tubes were centrifuged for 5 min at 2000 rpm and the excess amount of water was removed. For slide preparation, residues were transferred to vials and glycerine water was added. The residue was homogenized, no coloring was added, and a droplet of each residue was mounted on a slide with glycerine jelly; the mixture was stirred and sealed with nail varnish. Two slides per sample were prepared.
Slides were analyzed with a Leitz LM microscope at 400x or 1000x magnification. Where possible, slides were counted for up to 200 or more dinocysts, in addition to other associated palynomorphs. Dinocysts were counted at species level, whereas other palynomorphs were counted in broad categories (e.g., bisaccate pollen, other pollen, spores, inner linings of foraminifers [of >3 chambers in size] and acritarchs).
The postcruise studies are supplemented here by a few shipboard studies performed on core catcher material. Essentially, shipboard processing followed the technique described above, but a 20-µm stainless steel sieve was used (i.e., leading to the potential loss of small palynomorphs), and equipment was not as sophisticated as common modern laboratory setups. The shipboard results should therefore be taken as approximations.
Dinocyst taxonomy follows that cited in Williams et al. (1998). A species list, including remarks on previously undescribed taxa, is presented below. When Lycopodium numbers in a slide differed significantly from the expected calculated number (difference > 5% above or below the calculated value), the data were not included in absolute quantitative results. Images were captured using light-microscope photography (analog and digital) and scanning electron microscope (SEM). All material is stored in the collection of the Laboratory of Palaeobotany and Palynology, Botanical Palaeoecology, Utrecht University, The Netherlands.
The age models for Sites 1170-1172 as presented in Stickley et al. (this volume) are adopted here. Ages (in Ma) are indicated in Figures F2 and F3.