Leading Geologists Come To Tumut

December 30, 1999 Tumut & Adelong Times

Emeritus Professor Geomorphologist Cliff Ollier, a former Visiting Fellow at the ANU Centre for Resource and Environmental Studies (CRES), visited Tumut recently accompanied by Geologist Monica Yeung, at the invitation of the Bombowlee/Goobragandra Landcare Group.

At the fourth International Conference on Geomorphology in Italy in 1997, Dr Ollier presented a paper on Geomorphology and Mountain Building as he had earlier written Tectonics and Landscape Evolution in Southeast Australia, thus he was an excellent person to advise on the interpretation of the Geomorphology of Tumut.

Dr Ollier and Ms Yeung spent the weekend looking over the Bombowlee and Goobarragandra Valleys, identifying landforms and parent rock material which translate into soil and agricultural productivity.

In their travels they discovered a limestone deposit with inherent marine fossils, collected volcanic rocks from the active volcanic past and looked at road cuttings.

They described the Tumut Valley as having had a turbulent volcanic past where one tectonic plate was subducted under another taking sediment down below the earth's surface whilst magma is heating, rising and erupting as volcanoes.

Later, Monica Yeung presented the story of the Australian Geological development to a meeting of the Landcare community. She put into perspective in geological time, the creation of Australia's very old soils (soils which are 40 to 500 million years old, unlike New Zealand, North America, and Europe where many of the soils are considered to be only 7,000 to 10,000 years old) an Australian landscape which has been exposed to air and water for so long that basically everything had been washed out of it except the clays and iron.

Ms Yeung presented the past back to the estimated formation of the earth 4.5 billion years ago. She travelled through time from the singular landmass of Pangaea; to the separation of Gondwana (the prehistoric landmass comprising the future continents of the Southern Hemisphere).

She also presented the future of continental Australia as joined with the Asian subcontinent in 50 million years time. This union is predicted at this time because of the movement of the Australian continent northwards at 6cm a year.

Apart from speaking to the Landcare community, the Bombowlce/Goobragandra Landcare Group sponsored Ms Yeung to also speak to the composite 4/5/6 class at Franklin Public School and the geography students at the Tumut High School. The three presentations were tailored to each of the three audiences and were all well received.