'Fried Egg' may be impact craterBy Jonathan Amos
Science correspondent, BBC News, San Francisco
The Egg and its companion obtained by multibeam echosounder bathymetry
Portuguese scientists have found a depression on the Atlantic Ocean floor they think may be an impact crater.
The roughly circular, 6km-wide hollow has a broad central dome and has been dubbed the "Fried Egg" because of its distinctive shape.
It was detected to the south of the Azores Islands during a survey to map the continental shelf.
If the Fried Egg was made by a space impactor, the collision probably took place within the past 17 million years.
This is the likely maximum age of the basaltic sea-floor rock which harbours the feature.
"To be sure, we need to take samples and make a profile of the sediment layers to determine if there really is a central uplift from an impact," explained Dr Frederico Dias from EMEPC (Task Group for the Extension of the Portuguese Continental Shelf).
"We need also to see all the signatures that are consistent with a high velocity impact, like glasses from melting and, of course, debris; and what are called shatter cones (shocked rocks)," he told BBC News.
