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58.2 to 65.6 million years...in accord with what would be
expected from samples...with loss of argon content." 4 3 They
compare this with the revision of Manson's age (although there
the more recent measurement gave an older, not a younger age).
To the unwary, their discussion leaves the distinct impression that
the most recently obtained ages at Chicxulub are suspect and that
the original ones stand unchallenged. Officer and Page do not
reveal that two different laboratories conducted the modern age
measurements on the Chicxulub igneous rock, that they used the
highly precise argon-argon method, and that both gave precisely
the same result—exactly 65.0 million years. It is true that in one of
the studies, a few of the samples gave ages as low as 58.2 million
years, which the original authors attributed to alteration, but most
from that study gave 65.0 million years. Since argon loss causes
ages to be younger than they really are, not older, the older ages
are the more reliable. As testimony, in the other of the two dating
studies, three samples of the Chicxulub melt rock gave 64.94,
65.00, and 64.97 million years.
• Although they list among their references the paper by
Dartmouth scientists Blum and Chamberlain, who used isotopic
ratios to establish a genetic link between the Chicxulub melt rock
and the Haitian tektites, Officer and Page never actually mention
this result in their text.
• They do not reveal that the Chicxulub igneous rock has
anomalously high iridium levels. They acknowledge that it does
contain shocked minerals, but pass them off as "of the volcanic/
tectonic type." 4 4 (The original authors, however, clearly stated that
the shocked minerals show the multiple deformation planes indic-
ative of impact, features that have never been found in volcanic
rocks. 45 ) They do not mention that the Chicxulub melt rock is
reversely magnetized, consistent with (but not proof of) a K-T age.
• Although in an earlier section they discuss the visit of the
sedimentologists to Mimbral, in their section on the crater search
they never mention the conclusion that the sedimentologists
reached: that the Mimbral sediments "were deposited on short
time scales (more likely 100,000 seconds than 100,000 years)." 4 6
Chicxulub has met each of a reasonable set of predictions for
the impact crater, and then some. First, the concentric gravity pat-
terns and its huge size show that Chicxulub is not a volcanic feature
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