Geoscience Reference
In-Depth Information
the meteoritic fragments at Coon Mountain meant that a large and
valuable mass of meteoritic iron lay buried beneath the crater floor.
He began his investigation in 1902 and continued it for 27 years, stak-
ing a claim and forming a company to mine the iron ore. Barringer
sank exploratory shafts but found only the same fragments of mete-
oritic iron that had always turned up at Meteor Crater, as the cavity
had come to be called. In 1929 he asked astronomer F. R. Moulton to
calculate the amount of iron that should have been left behind. By
this time, impact science had advanced enough for Moulton to con-
clude that the impactor would not have buried itself into the ground,
it would have exploded, a fact of which no one in Gilbert's day was
aware. Furthermore, Moulton calculated the mass of the meteorite at a
mere 300,000 tons, far below Barringer's original estimate. Barringer's
role in the search for impact products came to a tragic end only a few
months later, just weeks after the stock market crash in 1929, when
he died of heart failure. Though only fragments of meteoritic iron ever
turned up at Meteor Crater, the work of Barringer and Moulton cre-
ated an important legacy—the knowledge that at least one terrestrial
hole in the ground was formed by an impacting meteorite.
Not long before Barringer died, Eugene Merle Shoemaker was
born. He was just slightly too young to serve in World War II." A
young man in a hurry, he rushed through Los Angeles's Fairfax High
School and the California Institute of Technology, emerging in 1948,
at age 20, with bachelor's and master's degrees (and having been a
school cheerleader along the way). He immediately joined the U.S.
Geological Survey and went to look for uranium ore on the Colorado
Plateau. Shoemaker recalled that one day in his first year with the
U.S. Geological Survey, on his way to breakfast, it dawned on him
that humans were going to "explore space." He thought, "I want to
be part of it! The moon is made of rock, so geologists are the logical
ones to go there—me, for example."
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Shoemaker was right—humans
were going to the moon, but unfortunately, medical problems pre-
vented him from achieving his lifelong goal of being one of them.
By the mid-1950s, Shoemaker, always to be found where the cut-
ting-edge geology was being done, was mapping nuclear bomb craters
at the Nevada test site. His work on the Colorado Plateau had drawn
to his attention a large cavity there that did not have a nuclear origin:
Meteor Crater. Having satisfied the descendants of Daniel Barringer
that he was not a disciple of Gilbert, in 1957 Shoemaker began the
modern study of Meteor Crater. He used the time-honored methods
of the field geologist: Study each rock unit close up and plot its posi-
tion to produce a geologic map, the universal medium by which geol-
ogists communicate.
