Coincidence in Arizona

Every true space cadet knows that the famous, 4,000-ft-wide crater near Winslow, Ariz, was made by a giant meteorite.

The U.S. Board of Geographic Names calls it "Meteor Crater" Airliners fly over it to show it to passengers, and the tourists it draws nourish a woebegone part of arid Arizona.

But science cannot let well enough alone. In the Bulletin of the American Association of Petroleum Geologists, Geologist Dorsey Hager attempts to prove that Meteor Crater is nothing but an ancient sinkhole that just happened to get peppered, late in its life, by a swarm of meteorites. According to Hager, Meteor Crater started as a steep-sided dome thrust upward several million years ago by geological forces. Its rock was splintered by distortion, and water penetrated to "evaporite" (salt) beds far below it. After millions of years, the water removed a lot of this soluble stuff, leaving enormous caverns. At last the roof fell in and parts of the walls tumbled after it, creating a pit.

All this happened, according to Hager, about 200,000 years ago. Much later, a great swarm of meteorites littered the pit and its vicinity with nickel-iron fragments.

It was this extraordinary coincidence, says Hager, that made the meteorite theory seem so plausible.

Hager, no conscious spoilsport, bases his argument on elaborate geological studies of the crater's surroundings. Except for the presence of meteoritic material, he says, there is little or no evidence to prove that the mound or the depression in its center is of meteoric origin. One of his strongest points is that the sides of the mound are made largely of white sand arranged in regular beds. This seems to point to the slow action of normal erosion, not to the sudden impact of a meteorite hitting the earth. Another strong point is that no large mass of meteoritic material has ever been detected below the bed of the crater.

Hager's theory has weaknesses, too. The rim of the crater shows great limestone blocks that look exactly as if they had been thrown there by some sort of explosion. And the long arm of coincidence had to strain itself to deposit so much meteoritic material on the only spot in the U.S.

that looks as if a great meteorite had hit it.

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