Discovery puts rock secrets on the radar

MAP-MAKING: Declan Radford has found a new way to survey the geology of inaccessible areas. Picture: Doug Dingwall

MAP-MAKING: Declan Radford has found a new way to survey the geology of inaccessible areas. Picture: Doug Dingwall

Thick bush slowed Declan Radford as he mapped hard-to-reach terrain near Waratah.

The University of Tasmania earth science honours student at times travelled one kilometre an hour as he walked.

In one section of bush, he covered 100 metres in 15 minutes in pursuit of his honours project.

His work will help overcome the barrier posed by the terrain to mineral exploration. 

As he surveyed the area, he cross-referenced previous state government mapping with information from radar images taken by NASA in 2000.

Mr Radford, from Yolla, has used the images to identify different areas of rock in the region in ways that can point to mineral deposits. 

By using ‘machine learning’, where computers analysed the images, he’s found a way to improve maps of the area’s geology.

“Radar has been used a little bit, but it’s been under-utilised in geological mapping,” Mr Radford said.

Traditional ways of mapping can take weeks or months, and is limited when areas are hard to access. 

Mapping some areas of the North-West has been difficult in the past.

“If you don’t have to walk a kilometre, it saves an hour,” he said.

Radar was a useful environmentally conscious tool for mapping remote areas, Mr Radford said.

NASA’s aerial radar maps were collected through a remote sensing system using microwave radiation to create an image of the earth’s surface.

Radar can see through clouds or vegetation and is unobtrusive unlike building roads, drilling holes or felling trees to assess an area’s geological composition.

Mr Radford’s research, using computers, may already have changed what is known about the area.

He found a new area of ultramafic rocks, once on the ocean floor but lifted up onto the Australian continent. 

“That’s quite an unusual thing to be happening,” Mr Radford said.

The rocks are usually pushed underneath the continents by tectonic plate movement.

In this area, it was pushed up onto land about 500 million years ago.

He now suspects a swathe of unmapped ultramafic rock lies along the area. While it’s mainly studied by scientists, it’s historically been mined for asbestos and osmiridium. 

His project could uncover minerals in the region that could be economic to mine. 

Director of Mines at Mineral Resources Tasmania Brett Stewart said Mr Radford’s work would help the industry.

“The 1:25,000 regional geology maps produced from this work will be used to identify areas that are more geologically complex and which have the potential to be of interest to the mining and exploration industries,” he said.

Mr Radford is taking a job in Kalgoorlie next year but hopes to continue his work another time. His new role will let him use machine learning more.

“One day I’d love to come back and explore this further.”

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