Quick Dips

Antarctic Secrets

The volcanoes of Antarctica's Marie Byrd Land hold the secrets of the cold continent's climatic past, and provide information on ancient geological processes. A New Zealand-British-US expedition has spent the summer investigating the volcanic evolution of Antarctica's Pacific Ocean rim. Earlier teams had to be content with short hit-and-run helicopter missions.

The team took samples of xenoliths, rock fragments brought up from the Earth's mantle and crust by lava. These xenoliths will be compared with ones found near Scott Base, in New Zealand and in Eastern Australia. Similarities would provide further support for the plate tectonics theory that the continents were once joined.

"[Xenoliths] offer us a unique opportunity to reconstruct cross-sections through the Earth's interior and to identify processes within it," said Dr John Gamble of Victoria University.

Scratch patterns made by glacial ice have provided information on the ebb and flow of the region's ice cap, as has analysis of lava eruptions. Lava forced up through ice has a different composition than that which bursts into air.

"Determining the age and chemical composition of lavas can...tell us from what, how deep and when an eruption occurred. That is incredibly valuable information for understanding our Earth's prehistory," said Dr John Smellie of the British Antarctic Survey.

Catherine Gilmore, DSIR Scott Base