(Appendix) Analysis of benthic foraminifera from ODP Leg 181 and DSDP Leg 90

• Main Authors: Hayward, Bruce William, Grenfell, Hugh R, Carter, Rowan, Hayward, Jessica J
• Format: Dataset
• Language: English
• Published: PANGAEA 2015
• Subjects: 181-1120B; 181-1120C; 181-1120D; 181-1121B; 181-1122C; 181-1123B; 181-1123C; 181-1124B; 181-1124C; 181-1125A; 181-1125B; 90-594; 90-594A; AGE; Calculated; Comment; Counting; Date/Time of event; Depth; composite; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Evenness of species; Event label; Foraminifera; benthic; flux; per unit sediment mass; planktic; Fragmentation index; Glomar Challenger; Intercore correlation; Joides Resolution; Latitude of event; Leg181; Leg90; Longitude of event; Number; Ocean Drilling Program; ODP; Sample code/label; Sample ID; Size fraction > 0.063 mm; sand; South Pacific/CONT RISE; Antarctic; New Zealand; Pacific; The Antarctic; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.856548; https://doi.org/10.1594/PANGAEA.856548

Canonical correspondence analysis indicates that the distribution of Neogene benthic foraminiferal faunas (>63 µm) in seven DSDP and ODP sites (500-4500 m water depth) east of New Zealand (38-51°S, 170°E-170°W) is most strongly influenced by depth (water mass stratification), and secondly by age (palaeoceanographic changes influencing faunal composition and biotic evolution). Stratigraphic faunal changes are interpretted in terms of the pulsed sequential development of southern, and later northern, polar glaciation and consequent cooling of bottom waters, increased vertical and lateral stratification of ocean water masses, and increased overall and seasonal surface water productivity. Oligocene initiation of the Antarctic Circumpolar Current and Deep Western Boundary Current (DWBC), flowing northwards past New Zealand, resulted in extensive hiatuses throughout the Southwest Pacific, some extending through into the Miocene. Planktic foraminiferal fragmentation index values indicate that carbonate dissolution was significant at abyssal depths throughout most of the Neogene, peaking at upper abyssal depths in the late Miocene (11-7 Ma), with the lysocline progressively deepened thereafter. Miocene abyssal faunas are dominated by Globocassidulina subglobosa and Oridorsalis umbonatus, with increasing Epistominella exigua after 16 Ma at upper abyssal depths. Peak abundances of Epistominella umbonifera indicate increased input of cold Southern Component Water to the DWBC at 7-6 Ma. Faunal association changes imply establishment of the modern Oxygen Minimum Zone (upper Circumpolar Deep Water) in the latest Miocene. Significant latitudinal differences between the benthic foraminiferal faunas at lower bathyal depths indicate the existence of an oceanic front along the Chatham Rise (location of present Subtropical Front), since the early late Miocene at least, with more pulsed productivity (higher E. exigua) along the south side. Modern Antarctic Intermediate Water faunal associations were established north of the ...