July 23, 2010
Impact Crater Found In The Sahara Desert
Researchers sifting through Google Earth images have discovered what may be the world's best-preserved small impact crater in a remote area of the Sahara desert in southwestern Egypt.
The immaculate, 148 ft. wide crater was likely excavated by a fast-moving iron meteorite, a few thousand years ago, scientists said Thursday.Dubbed Kamil, the crater is remarkably preserved when compared with most of the other craters on the Earth's surface, many of which are partially eroded.
The Kamil crater, by contrast, has retained much of its structure, and includes even the rays of ejected debris that were disbursed from the center as the meteorite made impact.
"This crater is really a kind of beauty because it's so well-preserved that it will tell us a lot about small-scale meteorite impacts on the Earth's crust," study leader Luigi Folco, meteorite curator at the Museo Nazionale dell'Antartide in Siena, Italy, told SPACE.com.
"It's so nice. It's so neat. There is something extraordinary about it," he said, adding that craters as pristine as Kamil are typically found only on Mars or on the moon, where there are fewer environmental and atmospheric forces to degrade them.
Vincenzo de Michele, a former curator of the Civico Museo di Storia Naturale in Milan, Italy, first identified the bowl-shaped Kamil crater in Google Earth satellite photographs.
Based on its size and characteristics, researchers believe Kamil was formed by the impact of an iron meteorite roughly 4.3 feet in diameter traveling at nearly 8,000 mph.
A team of geophysicists, including Folco, visited the site in Egypt's Sahara desert in February to confirm the discovery.
"The first real impression when we were in the field "” we could see with our eyes that it was really well preserved and a potential source of detailed information about this kind of event," Folco told SPACE.com.
Although researchers do not know the precise moment the meteorite hit the Earth, they estimate it was likely a few thousand years ago, which is fairly recent in geological terms.
There are approximately 175 confirmed impact craters on the Earth's surface, most of which are worn away.
Space rocks the size of large television sets routinely reach the Earth's atmosphere every month, but most burn up before they reach the surface. Many of the resulting fireballs are not observable because they occur over remote land areas or over the oceans, which cover two-thirds of the Earth's surface.
"This [the Kamil discovery] is important because small impacts are rather frequent on Earth "” on the order of one event every 10 to 100 years," Folco explained.
"Studying this crater is a good opportunity for scientists to get to a correct assessment of the hazard small impacts pose to the Earth and to devise mitigation strategies."
Folco is lead author on a report about the findings published in the July 23 issue of the journal Science.
Image Caption: At only 16 meters deep and 45 meters wide, you wouldn't call the Kamil Crater in the southwest corner of Egypt "Deep Impact". Indeed, there are much more massive and impressive meteor craters scarring the Earth. Yet this small but perfectly preserved depression, discovered in 2009 during a Google Earth survey, is a rare beauty. There are currently 176 known craters on Earth's surface, of which only 15 are less than 300 meters wide"”but all of these small craters have rapidly eroded and lost most of their original features. The Kamil Crater, however, has been well preserved, with the radial streaks of ejecta thrown out during impact still visible. And that's giving scientists a unique opportunity to study the characteristics of small-scale meteor impacts, researchers report online today in Science. The crater is in such pristine condition because it is geologically young (current estimates put the age at less than 5000 years) and because it escaped significant weathering, as it formed when extremely arid conditions were already prevalent in this remote part of Egypt. Craters like this one are typically found on planetary bodies in the Solar System that don't have atmospheres and therefore no weather systems to erode them. Credit: Museo Nazionale dell'Antartide UniversitÃ di Siena
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