Latest Oligocene to earliest Pliocene deep-sea benthic foraminifera from Ocean Drilling Program (ODP) Sites 752, 1168 and 1139, southern Indian Ocean

Abstract

Deep-sea benthic foraminifera provide important markers of environmental conditions in the deep-ocean basins where their assemblage composition and test chemistry are influenced by ambient physical and chemical conditions in bottom-water masses. However, all foraminiferal studies must be underpinned by robust taxonomic approaches. Although many parts of the world's oceans have been examined, over a range of geological timescales, the Neogene benthic foraminifera from the southern Indian Ocean have only been recorded from a few isolated sites. In this study, we have examined 97 samples from Neogene sediments recovered from three ODP sites in the southern Indian Ocean (Sites 752, Broken Ridge; 1139, Kerguelan Plateau; 1168, west Tasmania). These data cover a range of palaeolatitudes and water depths during the Miocene. More than 200 species of benthic foraminifera were recorded at each site and, despite their geographic and bathymetric separation, the most abundant taxa were similar at all three sites. Many of these species range from late Oligocene to early Pliocene demonstrating relatively little faunal turnover of the most abundant taxa during the key palaeoclimatic shifts of the Miocene. We illustrate and document the occurrence of the 52 most abundant species (i.e. those with >1 % abundance) encountered across the three study sites.