Molluscan stable isotope temperature estimates of the southwestern Ross Sea during the Early Oligocene and Early Miocene, CRP-2/2A and CRP-3, Victoria Land basin, Antarctica

摘要: Stable isotope analyses of marine bivalve growth increment samples have been used to estimate early Oligocene (29.4 - 31.2) Ma and Miocene (24.0 Ma) seafloor palaeotemperatures from the southwestern continental margin Ross Sea. Measured δ18O values average +2.5‰ in range between +1.26 +3.24‰ Oligocene. The results show that palaeoceanographic conditions McMurdo Sound during mid-Cenozoic were significantly different those today. minimum estimated spring through late summer seasonal temperature was 3°C 1 5°C This compares equivalent modern day <0.5°C within sound. Absolute seawater temperatures at <100 m depth order 5 7°C both time slices, compared -1.4 -1.9°C same area. are broad agreement with Mg/Ca estimates deep Atlantic foraminifera as well local terrestrial palynology palaeobotany.