X marks the spot: The Barringer Crater in Arizona, USA, is one of the few obvious craters known on Earth. Detecting hidden craters could be an important way to find new mineral wealth.
Credit: Wikimedia
OTTAWA: Meteorite craters are a rare find on Earth, numbering just 175 at last count, but a Canadian researcher has unveiled a new computer tool for locating hundreds more from the tiniest of clues.
The technique could be a significant one, as recent Australian research has suggested that meteorite craters are often associated with mineral wealth in the form of oil, gold and even diamonds (see, Meteor craters may hold untapped wealth, Cosmos Online).
Missing impacts
According to observations of the Moon and Mars, a small meteorite is predicted to impact Earth every 10 years. The Mars Orbiter Camera has shown, for example, that at least 20 such impacts formed on the Red Planet since 1999.
But of the 175 known craters on Earth, only five are less than 100 m in diameter, and fewer than 10 are less than 10,000 years old.
"Small impact events recorded on the surface of the Earth are significantly underrepresented based on expected magnitude-frequency relations," said Chris Herd, geoscientist at the University of Alberta, and the lead researcher behind the project.
Herd applied a new computer program to filter out trees and foliage from an aerial survey of a small crater discovered in 2007 near the town of Whitecourt, about 200 km west of Edmonton, Alberta.
Worldwide use
The aerial images taken by a forestry company using three-dimensional (3-D) mapping technology, once stripped of trees, revealed a bowl-shaped crater 36 m in diameter and 1,100 years old; now recognised as the youngest crater in Canada.
"This technology can be used to potentially reveal hundreds of meteorite craters around the world that are hidden by trees but unknowingly captured on aerial forest surveys," he said.
"As more craters are found and analyzed, existing theories on how many meteorites have hit Earth in the past and the frequency of future impacts will change," Herd said.
His research is published this week in the journal Geology.
