Otago Geology PhD student Olivia Truax will present the results of her research into Antarctic paleoclimate.

Ice-ocean-atmosphere interactions play an important role in governing the stability of the Antarctic ice sheets at their marine margins.

This project, (i) reconstructs the influence of mid-Holocene ice sheet retreat on the Ross Sea using multi-proxy records from five marine sediment cores, and (ii) assesses the impact of external forcing and internal climate variability on sea ice dynamics and water mass exchange.

Novel radiocarbon dating techniques are adopted to improve the chronologies of Antarctic marine sedimentary records, which are difficult to accurately radiocarbon date, and develop a robust chronology for a high-resolution reconstruction of relative paleointensity.

New insight into the linkages between global and Antarctic climate using Earth system models and paleoclimate data assimilation places Holocene reconstructions in a broader context.

The results presented here establish that modern freshening in the Ross Sea is outside the range of natural variability during the last 5,500 years. Intervals of enhanced ice sheet discharge, inferred from the oxygen isotopic properties of fossil diatoms, are observed as the Antarctic ice sheets underwent a rapid phase of retreat in the Ross Embayment between 6 and 5.5 ka, and since the mid-20th century.

Paleoclimate model simulations and reanalysis products support a link between late Holocene oceanographic changes inferred from Ross Sea sedimentary records, global cooling during the Little Ice Age, and mean state changes in the Southern Annular Mode and El Niño-Southern Oscillation.

Streaming details:

Zoom link: https://bit.ly/otagogeology