(Table 3) Age determination of sediment cores from the SW Pacific Ocean, supplement to: McCave, I Nick; Carter, Lionel; Hall, Ian R (2008): Glacial–interglacial changes in water mass structure and flow in the SW Pacific Ocean. Quaternary Science Reviews, 27(19-20), 1886-1908

• Main Authors: McCave, I Nick, Carter, Larry S, Hall, Ian R
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2008
• Subjects: Event label; DEPTH, sediment/rock; Depth, top/min; Depth, bottom/max; Sample comment; Age, dated; Age, dated standard deviation; Age, difference; Age, comment; Box corer; Gravity corer; Age, 14C AMS; Antarctic; Southern Ocean; The Antarctic; Weddell Sea; Ross Sea; Kerguelen; Pacific; New Zealand; Weddell; Antarc*
• Online Access: https://dx.doi.org/10.1594/pangaea.817599; https://doi.pangaea.de/10.1594/PANGAEA.817599

Eight- to ten-point depth profiles (from 1200 to 4800 m water depth) of oxygen and carbon isotopic values derived from benthic foraminifera, averaged over selected times in the past 160 ka, are presented. The data are from 10 sediment cores off eastern New Zealand, mainly North Chatham Rise. This lies under the Deep Western Boundary Current in the Southwest Pacific and is the main point of entry for several water masses into the Pacific Ocean. The benthic isotopic profiles are related to the structure of water masses at present and inferred for the past. These have retained a constant structure of Lower Circumpolar Deep Water-Upper Circumpolar Deep Water/North Pacific Deep Water-Antarctic Intermediate Water with no apparent changes in the depths of water mass boundaries between glacial and interglacial states. Sortable silt particle size data for four cores are also examined to show that the vigour of the inflow to the Pacific, while variable, appears to have remained fairly constant on average. Among the lowest Last Glacial Maximum values of benthic d13C in the world ocean (-1.03 per mil based on Cibicidoides wüllerstorfi) occurs here at ~2200 m. Comparable values occur in the Atlantic sector of the Southern Ocean, while those from the rest of the Pacific are distinctly higher, confirming that the Southern Ocean was the source for the unventilated/nutrient-enriched water seen here. Oxygen and carbon isotopic data are compatible with a glacial cold deep water mass of high salinity, but lower nutrient content (or better ventilated), below ~3500 m depth. This contrasts with the South Atlantic where unventilated/nutrient-enriched water extends all the way to the sea bed. Comparison with previous studies also suggests that the deeper reaches of the Antarctic Circumpolar Current below ~3500 m are not homogeneous all around the Southern Ocean, with the Kerguelen Plateau and/or the Macquarie-Balleny Ridges posing barriers to the eastward spread of the deepest low-d13C water out of the South Atlantic in glacials. These barriers, combined with inferred high density of bottom waters, restricted inter-basin exchange and allow three glacial domains dominated by bottom waters from Weddell Sea, Adelie Coast and Ross Sea to be defined. We suggest that the Ross Sea was the main source of the deep water entering the Pacific below ~3500 m. : Measured on planktonic and benthic foraminifera.