Stable isotope ratios measured on molluscan from the CRP sediment cores in the Ross Sea, Antarctica

• Main Authors: Lavelle, Mark, Fielding, Christopher R, Hall, Michael A
• Format: Dataset
• Language: English
• Published: PANGAEA 2001
• Subjects: 14.2 km at 096° true from Cape Roberts; Cape Roberts Project; Core wireline system; CRP; CRP-2; CRP-3; CWS; off Cape Roberts; Ross Sea; Antarctica; Sampling/drilling from ice; Cape Roberts; McMurdo Sound; Roberts Cape; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.510768; https://doi.org/10.1594/PANGAEA.510768

Stable isotope analyses of marine bivalve growth increment samples have been used to estimate early Oligocene (29.4 - 31.2) Ma and early Miocene (24.0 Ma) seafloor palaeotemperature from the southwestern continental margin of the Ross Sea. Measured d18O values average +2.5 ‰ in the early Miocene and range between +1.26 to +3.24 ‰ in the early Oligocene. The results show that palaeoceanographic conditions in McMurdo Sound during the mid-Cenozoic were significantly different from those of today. The minimum estimated spring through late summer seasonal temperature range was 3°C during the early Miocene and between 1 and 5°C during the early Oligocene. This compares to the equivalent modern day range of <0.5°C within the sound. Absolute seawater temperatures at <100 m depth were of the order of 5 to 7°C during both time slices, compared to modern day values of -1.4 to - 1.9°C in the same area. The results are in broad agreement with early Oligocene Mg/Ca temperature estimates from deep Atlantic foraminifera as well as estimates from local terrestrial palynology and palaeobotany.