Google Earth Reveals Major Impact Crater

An Australian geologist, Arthur Hickman, has discovered a rare meteorite impact crater in remote Western Australia using Google Earth to conduct research on channel ore deposits. It looks as though the Hickman Crater will be Australia's second largest preserved rim crater – one that has not eroded significantly from its original shape. The crater's rim, which is 80 per cent preserved, stands 30 meters above its floor, and consists mainly of rhyolite, a rock similar to granite.

An estimated 10,000 to 100,000 years old, the crater has an average diameter of 260 m and depth of about 50 m, second in size only to Australia's Wolfe Creek crater in Western Australia, which measures 875 m across and is 60 m deep.

Given its size and location, it's unusual that the crater was not seen prior to its accidental discovery. "It's like a lost world..." said Hickman.

The mystery of why the crater was not previously discovered may be answered by crater's location: it sits on top of a plateau and can only be seen from the air. Prior to the aerial viewing capabilities offered by services like Google Earth, the only way to see the crater would have been from light aircraft. However, since there are few viable ore deposits in the area north of Newman, there may have been no need for aerial investigation.

According to Australia's foremost meteorite expert, Alex Bevan of the Western Australian Museum, "it's difficult to imagine what else [the crater] could be" aside from the result of a meteorite impact. Bevan was not part of the discovery or research team, and has only viewed the crater using Google Earth.

The team believes that the meteorite was made of iron, with a diameter of roughly 10 m. The meteor is estimated to have traveled at five kilometers per second upon impact, releasing the energy equivalent of 200,000 to 300,000 tons of exploding TNT.

If the Hickman Crater is confirmed as an impact crater, it will be the 30th in Australia. According to the Earth Impact Database, a list of confirmed impact craters maintained by the Geological Survey of Canada and University of New Brunswick in Canada, there are currently only 174 confirmed impact craters worldwide.

The Hickman crater is located a mere 36 km from the mining town of Newman, which was Australia's most productive iron mine in the late 1960s.

Posted by Casey Kazan.

Links:

http://www.universetoday.com/2008/03/19/geologist-finds-a-meteorite-crater-in-google-earth/
http://www.cosmosmagazine.com/node/1934