Antarctica had forests, drilling samples show

Press, 26 October 1989, Page 16

Antarctica had forests, drilling samples show

PA Wellington Evidence of 50m global sea level fluctuations between 20 and 30 million years ago and beech forests in Antarctica has been gained from a New Zealand drilling programme at McMurdo Sound.

The director of Victoria University’s Antarctic Research Centre, Dr Peter Barrett, said core samples confirmed that sea-level changes were due to Antarctic ice melt-

ing. Studies of the core samples showed the nearby continental coast was formerly covered by beech forests, ' probably extending and receding at different times as the extent of the ice cover varied.

This conclusion was reached after a fossilised beech leaf was found in a core and after studying fossil pollen also discovered, said Dr Barrett. Traces of oil in the drillhole indicated the presence of significant vegetation in earlier

times. “The message to me is that we regarded the Antarctic ice sheet as a permanent feature of the planet, but in the past this was not the case,” he said. But if the atmosphere warmed up tomorrow it would probably take

many thousands of years for the 30 million cu km ice cap to melt. It was important not to overplay the news of previous sealevel fluctuations because of this long response time, said Dr Barrett. Fears that the “greenhouse effect” would bring about sea level rises were difficult to relate to findings from the drilling programme but if conditions were right such rises could certainly happen. “If the present largescale release of carbon dioxide into the atmosphere continues then the ultimate consequence will very likely be the melting of the ice-cap.” Important benefits could be gained from an improved understanding of the history of Antarctic

ice. Information gained would help scientists studying global climate changes attributed to the greenhouse effect. The Ross Dependency Research Committee, an Antarctic research committee advising the Government, recently published a book detailing conclusions drawn from the drilling programme — at $l.l million, New Zealand’s biggest research project in Antarctica. Titled “Antarctic Glacial History from the CIROS-1 Drillhole,” the book, edited by Dr Barrett, details the findings of 40 researchers who examined core samples recovered from under McMurdo Sound.

Drilling took place late in 1986 on ice 2m thick over sea 200 m deep. The hole, 12km off Victoria Land, went 702 m below the sea floor and is the deepest drilled on the continent.

Cores brought to the surface revealed history dating back between 22 million and 36 million years.