Alaskan Meteorite Crater Discovery

A 12.4 km (7.7 ml.) wide bowl-shaped depression south of Bettles has been identified as a meteorite crater by University of Alaska teacher Dr. P. Jan Cannon. Pilot-geologist Cannon used his own low-altitude aerial reconnaissance to help verify the identity of the feature that he first discovered using Landsat satellite images.

The meteorite crater is about 500 meters deep. Its center is occupied by Sithylemenkat Lake; sithylemenkat has the meaning "lake in the hills" in the Koyukon Indian language of the area. The crater is thought to have been formed during the latter part of the last ice age, about 100,000 years ago. The huge meteorite that struck the earth at this location 90 km south of Bettles may have weighed as much as 55 million tons. If there were any people in Alaska then, they must all have strongly felt seismic waves emanating from the impact.

Working without the benefit of satellite imagery, geologist Gordon Herreid had earlier investigated Sithylemenkat Crater and had assumed it was of glacial origin. However, he was bothered, and rightly so, by the lack of glacial features of the crater.

Several features combine to demonstrate a cataclysmic origin. Dr. Cannon has identified radial and concentric fracture patterns in the rocks surrounding the lake. The area also is rich in nickel, but there is no evidence of a parent ore body. Meteorites frequently are rich in nickel and when they break up on impact, the nickel and other components are generally distributed around the periphery of the impact crater.

Dr. Cannon has received considerable acclaim for his discovery. An article describing his finding has been published in Science (June 17, 1977), and the noted science writer Walter Sullivan described it in the New York Times.