Abstract:
In the Southern Hemisphere, sub-Antarctic islands are the only sentinels to preserve the geomorphic past for the vast Southern Ocean. They are unique not only in size, but also in geographic context when compared to the ice-capped southern continent of Antarctica, and the towering mountain ranges of Patagonia and New Zealand. The sub-Antarctic islands provide the only terrestrial record of Quaternary glaciations and climate within thousands of kilometres of ocean. These are primarily driven by changes in moisture delivery by the southern hemisphere westerly winds, and temperature, which is linked to past concentrations of carbon dioxide in the atmosphere, and the capacity of the oceans’ carbon sinks. This project aims to investigate landscape and climate interactions in a changing sub-Antarctic environment: past, present and future through (i) obtaining the ages of the basaltic lava through Ar-Ar dating to place it within a geological chronology which constrains landscape development and glaciation on Marion Island, (ii) to define Marion Island’s glacial history within more accurate temporal and spatial scales by using cosmogenic 36Cl surface exposure dating to explain how deglaciation has facilitated landscape development and impacted the colonisation and dispersal of biota, (iii) analyse novel dust and sea salt aerosol proxies in peat deposits to quantify changes in the Southern Hemisphere Westerly Wind regime during the last major reorganisation of the climate system (Termination 1: 18,000–11,000 years ago) to assist in determine how changes in the strength and position of the Southern Hemisphere Westerly Wind belt have controlled moisture delivery, and impacted on the ability of the Southern Ocean to modulate CO2 and (iv) to determine how aspects of the contemporary landscape (aeolian landforms) interact with the current dominant westerly wind patterns to predict for future landform change.
