(Table 1) Distribution and numerical abundance of foraminifera of sediment core CRP-3

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A foraminiferal fauna comprising c. 33 genera and c. 53 species was recovered from a suite of 156 Lower Oligocene sediment samples, mostly muddy sandstone and siltstone, selected over the 2.80 - 823.11 mbsf depth range in the CRP-3 drillhole. All foraminifers, except for 2 isolated specimens, occurred above 340 mbsf, with 54 of 103 samples from above this depth being fossiliferous. At a generic and even a specific level, the fauna contains many components for the present-day Antarctic foraminiferal biota, indicating that its origin is at least as old as early Oligocene. Foraminiferal assemblages represent a single biofacies which is characterised by low diversity, and by dominant and persistent occurrences of Cassidulinoides chapmani, other Cassidulinoides and Globocassidulina species, and Stainforthia sp. These taxa and commonly accompanied by Cibicides lobatulus, Epistominella exigna, Fissurina spp. Nonionella spp., and Oolina spp. Large miliolids occur as isolated specimens at various levels. Planktic species are absent, and agglutinated taxa occur only rarely and sporadically. Preservation generally is fair good, while absolute abundance is very low, with a maximum of c. 6 specimens/gram, and most samples containing <1 specimen/gram. These assemblages probably represent mid to outer shelf depth (50-200 m) in glacially influenced environments with a high sedimentation rate and poor oceanic connections. Although the CRP-3 fauna closely resembles the one from Foraminiferal Unit III as defined in CRP-2/2A (CRP-2/2A Science Team, 1999; Strong & Webb, 2000, hdl:10013/epic.28260.d001), absence of some species, and the first records of others in the uppermost CRP-3 section, is consistent with an interpretation of minimal overlap between the CRP-2/2A and CRP-3 sediments. The fauna also appears correlative with the Globocassidulina-Cassidulinoides-Trochoeiphidiella Assemblage Zone from lower DSDP-270, and with faunas from the lower but not lowermost, section at CIROS-1.

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