Geologists studying the US state of Wyoming have discovered a type of meteorite crater never before seen on Earth, the result of a powerful impact millions of years before dinosaurs walked the planet.
In a study published in the Geological Society of America Bulletin, the team of German and American scientists describes a field of secondary impact craters they believe was formed by the material ejected from a larger, primary meteor impact around 280 million years ago. Secondary craters are common on rocky bodies in the Solar System with no or thin atmospheres, such as the Moon and Mars, but rare on objects with thick atmospheres such as Earth or Venus.
