The Great Desert



Arizona's Meteor Crater is the youngest and best-preserved meteorite crater on the Earth. Meteorites fall onto the Earth every day, but very rarely is one large enough and strong enough to pass through the atmosphere without being slowed down. The Meteor Crater meteorite was iron-nickel metal, and is estimated to have been ~50 meters in diameter, and have weighed several hundred thousand tons. It hit the Earth at a speed near 20 kilometers per second (~50,000 mph), and excavated the Meteor Crater in a few seconds. Meteor Crater was first described by white folk in 1871 and named Franklin's Hole. Settlers in the area renamed it Coon Butte. Geologist G.K. Gilbert, who first interpreted the Moon's craters as impacts, studied Coon Butte and decided it was most likely a maar crater, from a volcanic explosion. In 1902, Daniel M. Barringer, a New Jersey steel magnate, investigated the site as a possible source of iron, and became convinced that it was a meteorite impact crater. His work yielded no iron mine, but finally swayed scientific opinion.

Meteorite impact cratering is the most important geologic process that shapes the surfaces of solid planets and moons. Impact crater like Meteor Crater (and MUCH larger) are abundant on Mars and most other planets and moons). Impact craters are rare on geologically active places like the Earth, Venus, and Jupiter's, but not because meteorites never hit there. Impact craters formed on all of the planets and moons, but were covered over by lava flows (especially on Venus and Io) or erased by erosion and plate tectonic processes (on Earth).

Crater on Skyline
Tuff and Pumice

From Interstate highway 40 (old route 66), the Meteor Crater is completely uninspiring. It looks like a low ragged butte, much like the many other mesas and tables scattered across the Colorado Plateau.
A close-up of Coon Butte / Meteor crater from the Highway. This outline is typical of meteorite impact craters: a ragged rim raised above the surrounding plains, but much broader than tall. The lumpy hills outside the rim are ejecta, rocks tossed out of the crater during the meteorite impact. This silhouette distinguishes impact craters from volcanos, except maar craters and caldera complexes (which are much larger).

Next - Meteor Crater 2  | Back to Workshop Index
Back to "The Great Desert"
LPI home page | LPI Education Resources Page
Copyright Allan Treiman, LPI.
Updated 09/06/03.
Comments to