The Odessa Meteorite

Odessa meteorite specimen, cut and polished to display the Widmanstatten pattern

Well over 20,000 years ago, a cluster of nickel-iron meteorites slammed into what is now West Texas. They left a main explosion crater that was a tenth of a mile in diameter and at least 75 feet deep, in addition to several smaller craters. Due to wind and rain, the main crater -- one of the best-studied craters in the world -- is now only on average about 6 feet below the surrounding plain, but excavations of the fill material have turned up Pleistocene elephant and horse fossils, which are what have been used to date the fall.

Since the 1920's, when the crater was recognized as being meteoritic in origin, 10 tons or more of weathered meteorite fragments have been dug from the area, some of them up to eight miles away. More fragments have disintegrated into completely oxidized meteoritic shale in the intervening centuries. The main mass of the meteorite is believed to have vaporized on impact. Estimates put that at a minimum of 500 tons.

The structure of the Odessa meteorites is very similar to that of the Canyon Diablo meteorites, from Barringer Crater in Arizona. They are coarse octahedrites, and display the distinctive Widmanstätten pattern when cut and polished.

The remains of the crater -- still 500 plus feet in diameter, but on average only about 6 feet below the surrounding plain -- have been designated a National Landmark, and can be seen just south of Interstate 20, west of Odessa, Texas. More information can be found at The Odessa Meteor Crater, as well as in Rocks From Space, by O. Richard Norton.

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