Meteor Crater came to the attention of scientists after American settlers encountered it in the 19th century. The crater was given several early names, including "Coon Mountain", "Coon Butte", "Crater Mountain", "Meteor Mountain," and "Meteor Crater."
Daniel M. Barringer was one of the first people to suggest that the crater was produced by a meteorite impact, with the Barringer family filing mining claims and purchasing it and its surroundings in the early 20th century. This led to the crater also being known as "Barringer Crater." Meteorites from the area are called Canyon Diablo meteorites, after the convention of naming the meteorite after the closest post office, which was
Canyon Diablo, Arizona. The
canyon itself passes to the west and crosses the
strewn field, where meteorites from the crater-forming event are found. The crater was initially assumed to have been formed by a volcanic
steam explosion; evidence of geologically recent volcanic activity occurs across this part of Arizona – the southeastern edge of the
San Francisco volcanic field is only about northwest of Meteor Crater.
Albert E. Foote In 1891, mineralogist
Albert E. Foote presented the first scientific paper about the meteorites of Northern Arizona. Several years earlier, Foote had received an iron rock for analysis from a railroad executive. Foote immediately recognized the rock as a meteorite and led an expedition to search and retrieve additional meteorite samples. The team collected samples ranging from small fragments to over . Foote identified several minerals in the meteorites, including microscopic diamonds. His paper to the Association for the Advancement of Science provided the first geological description of Meteor Crater to a scientific community.
Grove Karl Gilbert In November 1891,
Grove Karl Gilbert, chief geologist for the
U.S. Geological Survey, investigated the crater and concluded that it was the result of a
volcanic steam explosion. In 1892, Gilbert would be among the first scientists to propose that the Moon's craters were caused by impact rather than volcanism.
Daniel M. Barringer Mining engineer and businessman Daniel M. Barringer suspected that the crater had been produced by the impact of a large
iron meteorite. The theory that the crater was of meteoric origin had been met with skepticism. At the time, the craters visible on the Moon were thought to be
volcanic, and no one had conclusively proved that impact craters existed. Barringer had amassed a small fortune as an investor in the successful Commonwealth Mine in
Pearce,
Cochise County, Arizona. Barringer believed that the bulk of the Meteor Crater impactor could still be found under the crater floor. Impact physics was poorly understood at the time, and Barringer was unaware that most of the meteorite had vaporized on impact. Barringer incorporated a company, the Standard Iron Company, and staked a mining claim on the land, hoping to mine the asteroid that had produced the crater. He estimated from the size of the crater that the meteorite had a mass of 10 million tons. Barringer spent 27 years trying to locate the nonexistent deposit of
meteoric iron, and drilled to a depth of , but no significant deposit was ever found. Barringer was politically well-connected. He received a
land patent signed by
Theodore Roosevelt for 640 acres (1 sq mi, 260 ha) around the center of the crater in 1903. The Meteor post office closed on April 15, 1912, due to disuse. In 1929, astronomer
F. R. Moulton was employed by the Barringer Crater Company to investigate the physics of the impact event. Moulton concluded that the impactor likely weighed as little as 300,000 tonnes, and that the impact of such a body would have generated enough heat to vaporize the impactor instantly. Barringer died just ten days after the publication of Moulton's second report. By this time, "the great weight of scientific opinion had swung around to the accuracy of the impact hypothesis ... Apparently an idea, too radical and new for acceptance in 1905, no matter how logical, had gradually grown respectable during the intervening 20 years."
Harvey H. Nininger Harvey Harlow Nininger was an American
meteoriticist and
educator, and he initiated a widespread interest in the scientific study of meteorites in the 1930s, and assembled the largest personal collection of meteorites up to that time. While based in
Denver,
Colorado, Nininger published the first edition of a pamphlet titled "A Comet Strikes the Earth", which described how Meteor Crater formed when an asteroid impacted the Earth. In 1942, Nininger moved his home and business from Denver to the Meteor Crater Observatory, located near the turn-off for Meteor Crater on
Route 66. He christened the building the "American Meteorite Museum" and published a number of meteorite and Meteor Crater-related books from the location. He also conducted a wide range of research at the crater, discovering impactite, iron-nickel spherules related to the impact and vaporization of the asteroid, and the presence of many other features, such as half-melted slugs of meteoric iron mixed with melted target rock. Nininger's discoveries were compiled and published in a seminal work, ''Arizona's Meteorite Crater'' (1956). Nininger's extensive sampling and fieldwork in the 1930s and 40s contributed significantly to the scientific community's acceptance of the idea that Meteor Crater formed by the impact of an asteroid. Many of his discoveries were later observed at other relatively fresh impact craters, including
Henbury and
Monturaqui. Nininger believed that the crater should be a
national monument and, in 1948, he successfully petitioned the American Astronomical Society to pass a motion in support of nationalizing the crater by making "the unauthorized—and false—claim that the [Barringers] would be receptive to a fair purchase for the crater."
Eugene M. Shoemaker {{multiple image
Eugene Merle Shoemaker continued investigations at the crater. A key discovery was the presence in the crater of the minerals
coesite and
stishovite, rare forms of
silica found only where
quartz-bearing rocks have been severely
shocked by an instantaneous overpressure. Shocked quartz cannot be created by volcanic action; the only known mechanisms of creating it are naturally through
lightning or an
impact event, or artificially, through a
nuclear explosion. In 1960,
Edward C. T. Chao and Shoemaker identified coesite at Meteor Crater, adding to the growing body of evidence that the crater was formed from an impact generating extremely high temperatures and pressures. He confirmed what F.R. Moulton and H.H. Nininger already proposed: the impact vaporized the vast majority of the impactor. The pieces of
Canyon Diablo meteorite found scattered around the site broke away from the main body before and during the impact. Shoemaker published his conclusions in his 1974 book, the
Guidebook to the geology of Meteor Crater, Arizona. Geologists used the nuclear detonation that created the
Sedan crater, and other such craters from the era of
atmospheric nuclear testing, to establish upper and lower limits on the kinetic energy of the meteor impactor. ==Geology==