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idea I later stopped over at the Air Force Base in Rantoul, Illinois, and hitchhiked to Kent-
land. 10
Shatter cones are structures in which grooves in solid rock radiate outward like the
feathers of a badminton shuttlecock or a horse's tail. Later they would turn up in
rocks blasted by underground nuclear tests. They have never been found in volcan-
ic rocks.
Shatterconesareespeciallyeasytospotinfine-grainedrockslikethelimestones
at Kentland, and in no time at all Dietz found them. When he figuratively rotated
thedeformedrocksbacktotheiroriginalhorizontalposition,theapexoftheshatter
cones pointed straight up, as though the forces had been “cosmic rather than vol-
canic” (21). Dietz visited two other potential impact structures in Tennessee and
concluded that impact had caused both of them, as well as each of Bucher's putat-
ive cryptovolcanic structures.
Immediately after World War II, while supervising the oceanographic research
on Admiral Richard E. Byrd's last Antarctic expedition, Dietz's fertile mind
wandered again to the Moon's surface features. He wrote up his thoughts and sub-
mitted them in a paper to the Journal of Geology , whose editor remained Rollin T.
Chamberlin. Dietz's paper appeared in 1946; he was the first, he wrote, since Gil-
bert to propose an impact origin for lunar craters. 11 Dietz was unaware that Alfred
Wegener had done so twenty-five years earlier and had reached exactly the same
conclusions.
One of the papers at the 1964 conference on “Geological Problems in Lunar Re-
search” dealt with Dietz's suggestion that meteorite impact had created the giant
Vredefort Ring structure in South Africa. In the discussion that followed, B. B.
Brock of the Anglo-American Corporation of South Africa revealed what may
have been the primary reason that geologists rejected impact cratering on the Earth
and on the Moon: “To call on astronomy to solve our tectonic problems would be
to minimize the usefulness of geology.” 12 In his 1963 article, Walter Bucher had
said much the same:
Before we look to the sky to solve our problems miraculously in one blow, we should consider
the possibility that cryptoexplosion structures and explosion craters may hold important clues
to processes going on at great depth. Distrust in traditional thinking should not deter us from
looking hard at all aspects of the problem. Doing so will probably yield more useful results
than computing possible velocities of imagined meteorites. 13
To persuade geologists, accustomed to looking down for their evidence, to look
up would require something new, something undeniable. A close-up photograph of
the Moon, or a moon rock sitting on a laboratory bench, for example.
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