The first geological report on the gigantic Northern Arizona Crater, in 1891, focused not on the crater itself but on tiny diamonds found in nearby meteorites. Back then, researchers assumed that only an explosive volcanic eruption could make such a large crater. But after more careful study of the meteorites and altered rocks in and around the crater, scientists realized that it must have formed during a massive meteorite impact.
The story of Meteor Crater, also called Barringer Crater, began 50,000 years ago with an asteroid roughly twice as wide as this hall hurtling to Earth at about 50 times the speed of sound. The explosive force of its impact blasted out 175 million tons of limestone and sandstone, sprayed molten rock upward and tossed chunks of meteorite several miles away.
Once the dust and debris settled, the crater sat quietly for tens of thousands of years as the Arizona climate gradually grew drier, helping to preserve evidence of the impact.
Topic: Earth Science
Keywords: Meteorites, Asteroids--Collisions with Earth, Meteor Crater (Ariz.), Earth (Planet)--Surface, Astrogeology, Meteorite craters, Collisions (Astrophysics)
This is the second-largest surviving fragment of the Canyon Diablo meteorite that formed Meteor Crater; it probably broke off when the main mass hit the atmosphere.
Both the pulverized rock, called rock flour, and the foamy-looking lechatelierite shown below are made of glass.
Shocked, melted and pulverized rocks helped prove that meteorite impacts can make craters.
Meteor Crater, also called Barringer Crater, formed in a meteorite impact.
Tens of thousands of Canyon Diablo meteorite fragments were found at Meteor Crater—most were much smaller than this 200 kilogram (440 pound) sample.