field notes / By Barry Evans

Impact! 50,000 years B.C.

(May 21, 2009)  “Whatever created this hole was one scary mother,” I thought, two weeks ago, standing on the rim of what’s billed as “the first proven, best-preserved, meteor crater on earth.” It’s so obviously formed by a meteorite (a meteorite is a meteor that makes it to earth before being vaporized) — perfectly round, steep sided — that it might have been imported directly from the moon. Yet until 50 years ago, most scientists thought it was probably the caldera of an ancient volcano.

We now know that some 50,000 years ago, a third-of-a-million ton lump of nickel-iron slammed into what was then a grassy plain 40 miles east of present-day Flagstaff, Ariz. The explosion would have dazzled — right before obliterating — any wooly mammoths or North American camels in the area. Equivalent to some 150 Hiroshima-size atomic bombs, the impact scattered hundreds of millions of tons of rock onto the surrounding countryside. About half the bulk of the meteorite was vaporized, leaving — in theory — a rich lode of metal waiting to be discovered and mined.

GALLERY >

That was what mining engineer Daniel Barringer believed, anyway, when President Theodore Roosevelt signed a patent granting him the rights to a square mile of land around the center of the crater in 1903. For the next 25 years, Barringer’s Standard Iron Company searched fruitlessly for the remaining metal, hoping to extract it and make huge profits for the shareholders. Years after those efforts were abandoned, the Barringer family made the best of it by turning the huge crater into a tourist attraction, and today you can tour the excellent visitor center and take a guided walk along part of the north rim.

Very little of the actual meteorite has ever been found, which is why the volcanic origin was once favored. Not until 1960, when planetary scientist Eugene Shoemaker identified rare forms of dense silica (created only by nuclear explosions or impacts) at the bottom of the crater, was the meteorite origin completely accepted.

Louisa and I spent a fine couple of hours in the museum and along the crater rim, trying (not very successfully) to imagine the force of the explosion that rent such a vast crater in our planet’s crust not so long ago. It’s well worth a visit — we give it four-and-a-half stars.

Barry Evans’ preferred means of demise is to be hit by a meteorite, especially in Old Town Eureka, where he lives.

CAPTIONS

The Barringer meteor crater, nearly a mile across and a quarter mile deep, 40 miles east of Flagstaff, Arizona. (Author photo panorama)

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