ODP Site 1138A was drilled in January 1999 at 53°33.1´S, 75°58.5´E in the southern Indian Ocean in 1141.4 m water depth. The material studied is from Cores 183-1138A-52R through 63R (486.7-601.8 mbsf) and consists of the Campanian-Maastrichtian section and one sample from the overlying Danian. Planktonic foraminifers and calcareous nannofossils provide the age control (Petrizzo, 2001) employed in this paper, supported by several species and subspecies of the Bolivinoides complex. Material from Cretaceous sediments deeper in the section is the subject of Holbourn and Kuhnt (in press). These samples were taken by routine ODP rotary coring techniques.
While conducting fishing operations in the region, the fishing vessel Petuna Explorer accidentally recovered yellowish white weakly indurated chalk from the seafloor in 420 m depth at 51°25.3´S, 75°34.52´E, on 14 April 1997. This sample yields a very small residue from processing, indicating that it is a nannofossil/foraminifer ooze or chalk. Other components are very well preserved radiolarians and ostracodes. It contains a diverse, very well preserved foraminifer fauna. The planktonic fauna from this sample is recorded and analyzed for age and for faunal province relationship.
Core E54-7 was taken by Eltanin in 1972 at 55°52.78´S, 81°07.09´E in 4304 m water depth. Although the complete core was 5.27 m long, deeper parts of the core are highly disturbed and only the upper 2.12 m was studied in detail.
Samples were soaked in water with Calgon. The dredge and core E54-7 material disaggregated fully and easily with this process, perhaps reflecting a lack of overburden pressure at any stage in their history. Material from Site 1138 is much more compact, perhaps a result of higher, longer-term overburden pressure. The ODP material disaggregated only partially by this process and then was further crushed gently and reprocessed. This was generally successful, and the residues contain very little that has not disaggregated. Residues from all cores and localities are generally very small, reflecting the fact that the sediments are dominantly nannofossil oozes with a small foraminifer content. Site 1138 material, although entirely adequate for study, is not as well preserved as that from the dredge or the core E54-7 material.
Specimens figured on the plate are housed in the collections of the School of Earth Sciences, University of Tasmania (UTES), and the accession number in that collection is indicated on the figure explanation. The dredge sample is housed in the same collection as UTES147031.
Material studied is that coarser than 125 µm.