Scratches left in rock by ancient ice-sheet near Orroroo

A woman bushwalker has found evidence of an ancient glacier at Pekina Creek.

She is Aileen Preiss who is the aunt of Mount Remarkable District Council Mayor Colin Nottle.

Mrs Preiss stumbled on “striations” left on rock by the moving glacier thousands of years ago.

She hopes her discovery will spark renewed interest in tracing the history of ice-sheets in the region.

Mrs Preiss was with her husband, renowned South Australian geologist Wolfgang Victor Preiss, when she made her discovery.

“For 50 years I have travelled with Wolfgang looking at geology, always hoping I might find something interesting that he had not noticed, but there was rarely anything of any significance until June 6, 2015,” she said.

“We were enjoying a return visit to Pekina Creek at Orroroo. 

“It was a beautiful day. The scenery is so typically South Australian and this area holds a wealth of interesting features that should be treasured and appreciated more.

“The walking track is rather neglected. One needs to be careful not to step into the rusted-out reservoir water pipe holes. The old signs that once encouraged picnickers to explore the area have faded.

“Halfway to the reservoir we arrived at the unattractive wire caged area that continues to protect the siltstone rock outcrop where the main display of Aboriginal carvings can be viewed.

“Wolfgang was carefully checking the rock types and orientations.

“I was more interested in the carvings on a smooth polished rock surface when a feature caught my eye.

“I said, ‘these marks look like glacial striations’. To my surprise, he said, ‘you are right!’ The carvings cut through the striations, or scratches, in the rock. The sun must have been just at the correct angle for me to see the striations as they are not easy to see otherwise.

“But they are very interesting when you think of a glacier sliding over these outcrops before the Aboriginals carved the rock, probably thousands of years ago.

“We hope more evidence of ice-sheets in the elevated parts of eastern South Australia will be found and more of the exciting story of past climate change will be revealed.”

“I also hope publicity about this may encourage a revitalisation of Pekina Creek Reserve.”

A glacier slid over these outcrops before the Aboriginals carved the rock, probably thousands of years ago.

Aileen Preiss

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