The Battle for Impact Theory
Barringer’s conclusion about the impact origin of the crater was still only a hypothesis. In order to raise money for his planned mining venture, he had to convince the scientific community that he was correct.
Photos of shale balls found at the crater, from Barringer’s 1909 paper.
Barringer’s core samples from the crater, including meteoritic material.
Barringer and Tilghman set about gathering evidence in support of their claim. Before long, the search for a nickel-iron fortune had become deeply entangled with Barringer’s quest for the prestige of being the first person to prove the impact origin of the crater.
In 1906, and again in 1909, Barringer and Tilghman presented their arguments for the impact origin of the crater to the Academy of Natural Sciences in Philadelphia. They included:
- The presence of millions of tons of finely pulverized silica, which could only have been created by enormous pressure.
- The large quantities of meteoritic iron, in the form of globular “shale balls”, scattered around the rim and surrounding plain.
- The random mixture of meteoritic material and ejected rocks.
- The fact that the rock strata in the rim and on the surrounding plain appeared to have been deposited in the opposite order from their order in the underlying rock beds, indicating that the topmost material had been thrown out of the crater first, followed by the rocks from the lower strata.
- The absence of any naturally occurring volcanic rock in the vicinity of the crater.
Not all of their audience was convinced. One writer said of Barringer’s 1909 address to the National Academy of Sciences at Princeton: “[S]ome persons could scarcely conceal their derisive thoughts. Nevertheless… Barringer ploughed through his paper, painful though it must have been for him, until he completed it.”
The Battle for Impact Theory
It was probably significant for the future of the controversy that Barringer’s first paper began with a tactless reference to G. K. Gilbert. As he later recalled, “I gave expression to my surprise that any experienced geologist could have failed to recognize from the evidence, so plainly to be seen, the fact that this crater could not be the result of volcanic forces.”
“I gave expression to my surprise that any experienced geologist could have failed to recognize… that this crater could not be the result of volcanic forces.”
Geologists at the USGS were offended. Some of Gilbert’s colleagues argued vigorously against the impact hypothesis, and even ridiculed Barringer’s conclusions. And Gilbert’s great prestige kept others silent, even though they privately admitted that Barringer was right.
Barringer stubbornly persisted, inviting scientists to visit the crater and eventually winning more and more converts. But Gilbert and the U.S.G.S. refused to comment publicly. Barringer’s outsider status, his forceful and opinionated personality, and his scornful dismissal of contrary opinions, could not have endeared him to the scientific establishment of his time. As he wrote in 1912 to the inventor Elihu Thomson, “They know in their heart of hearts that I have got them beaten and yet they are not men enough to admit it.”
Geologist George P. Merrill
In 1908 Barringer’s conclusions were championed by the eminent geologist George P. Merrill. Merrill analyzed two new varieties of sandstone discovered by Barringer at the crater, and concluded that both must have been produced by a brief but enormous pressure, greater than any known to occur through terrestrial processes. Merrill also pointed to the undisturbed rock beds below the crater, which proved that the force that created the crater could not have come from below.
At around the same time Barringer made another discovery. All previous explorations of the crater had been based on the assumption that the meteorite struck from directly above. Barringer, however, began to test that assumption by firing rifles into mud at various angles, and discovered that a projectile traveling at an oblique angle at high velocity would nevertheless create a round hole.
Because of the upward bulge of the south rim, and the symmetrical distribution of meteorite fragments around a north-south axis, he concluded that the meteorite was actually located under that rim, and all further drilling was carried out there. By this time, Barringer was estimating the size of the meteorite at above a million tons.