Radiolarian faunas have frequently been used in Antarctic Neogene biostratigraphy, beginning with the work of Hays (1965), Chen (1975), and the more recent work of Abelmann (1990, 1992), Caulet (1991), and Lazarus (1990, 1992). Because of the highly endemic nature of Antarctic Neogene radiolarian faunas, calibration of the events by direct comparison to low-latitude zones has not proved feasible. Diatom floras are similarly affected, and, for at least the later Neogene, it is not possible to use standard low-latitude planktonic foraminifers or calcareous nannofossil events for calibration purposes, as the marker taxa are generally absent in Southern Ocean sediments. The calibration of the current zonation (Fig. F1) to the geologic timescale is largely based on the biomagnetostratigraphic syntheses of Ocean Drilling Program (ODP) Legs 113, 119, and 120 (Gersonde et al, 1990; Barron et al., 1991; Harwood et al., 1992). In these previous studies, some uncertainties remain, particularly in the ranges and calibration of taxon events in the latest Miocene and early Pliocene intervals, where hiatuses have made interpretation of the sections difficult. Obtaining a clear picture of the true sequence of events requires piecing together data from a large number of (individually incomplete) sections. During ODP Leg 183 at Site 1138, a section was recovered from the Kerguelen Plateau with well-preserved radiolarian faunas of late Miocene to early Pliocene age. We have studied these faunas with the dual aims of providing age estimates for this site and documenting the ranges of species during this time interval in a section that may eventually assist in resolving the remaining uncertainties in the Antarctic Neogene radiolarian zonation. In this paper, we report the primary stratigraphic results for the site. Comparative analysis with other Antarctic sites will be the subject of a future paper.