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T HE R ED D EVIL
Having concluded that the crater is likely to be in North America
narrows the field, but it still leaves an impracticably large area to
explore. When confronted with such a task, the intelligent geolo-
gist heads not for the field but for the library, there to scour the
literature for reports of unusual K-T deposits and descriptions of
circular geophysical patterns. The most diligent crater sleuth and
literature searcher was Alan Hildebrand, a doctoral candidate at the
University of Arizona who is now with the Geological Survey of
Canada. 8 One report in particular caught his eye: the description
by Florida International University's Florentin Maurrasse of a set of
peculiar, late Cretaceous rocks exposed at the top of the Massif de la
Selle on the southern peninsula of Haiti. 9 Maurrasse depicted a thick
limestone sequence, the Beloc Formation, that contained a 50-cm
layer that he thought was volcanic. In June 1989 Hildebrand visited
Maurrasse and, as soon as he saw the Beloc samples, recognized them
as altered tektites of impact rather than volcanic origin. Hildebrand
then went to Haiti himself to collect from the Beloc Formation, and
found the dual K-T layering that by that time had been described at
many North American sites. In this case, however, the lower ejecta
layer was about 25 times as thick as elsewhere and contained the
largest tektites and shocked quartz grains ever found, suggesting that
the Haitian site was close to the K-T target. Hildebrand and his col-
leagues estimated that ground zero was within 1,000 km of Haiti.
In May 1990, Hildebrand and William Boynton reported that the
only crater candidate their literature search had turned up was a
vaguely circular structure lying beneath 2 km to 3 km of younger
sediment in the Caribbean Sea north of Colombia. 1 0 They acknowl-
edged, however, that an impact at this seafloor site probably could
not have provided the continental grains and rock fragments found in
the boundary clay. Hildebrand and Boynton did note, almost as an
afterthought, that in 1981, at the annual meeting of the Society of
Exploration Geophysicists, geologists Glen Penfield and Antonio
Camargo had reported circular magnetic and gravity anomalies from
the northern Yucatan Peninsula and had speculated that buried there,
beneath younger sedimentary rocks, might lie an impact crater.
By 1990, a peculiar kind of sedimentary rock deposit of K-T age
had been found at several sites rimming the Gulf of Mexico. To the
pro-impactors it appeared that these rocks were formed by giant
waves, or tsunami, of the kind that a meteorite splashdown in the
ocean would have produced. Since the Colombian basin site turned
out to be the wrong age, the giant wave deposits helped to persuade
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