Oct. 6, 2006 — New research on a few of the more than 1,300 enigmatic craters found deep in Egypt's western desert has scientists scratching their heads.
The craters look like they were created by a spectacular ancient rain of meteors, or perhaps from a vast eruption of steam and gas from inside the Earth. Or maybe from something else entirely.
"It is a strange and new thing," said Philippe Paillou of the Observatoire Aquitain des Sciences de l'Univers in Floirac, France. Paillou is the lead author of a report on an expedition to the remote landscape of Egypt's Gilf Kebir region in the October issue of the Journal of African Earth Sciences.
"Right now I cannot tell you I believe this is hydrothermal (explosive steam) or (meteor) impact," he said.
Hydrothermal vents can look like craters at the surface, Paillou explained, because eons of wind and rain nibble away at the surface, exposing more and more of the ice-cream-cone-shaped vent over time.
To find out if that was the case, Paillou and colleagues from France, Germany, South Africa, Egypt and the United States visited more than 60 of the craters in 2004. Digging was impossible because of the terrain and remote location, so the researchers used ground-penetrating radar to peer beneath the craters.
"The problem is that ground-penetrating radar doesn't show this kind of tube under the surface," Paillou told Discovery News. On the other hand, the craters, which look like classic volcanic cinder cones, show no signs of being volcanic.
"When you go there you don't find volcanic rock or ash," Paillou said. "So it cannot be a classical volcanic feature. That's why we didn't propose any volcanic hypotheses."
So are they the remains of a meteor that fragmented and peppered the region with impacts? To test that idea, Paillou and his team looked at the minerals in the rocks from some of the craters in search of telltale "shocked" minerals.
