THE VOLCANIC RIVAL - Night Comes to the Cretaceous - page 83

CHAPTER 6

THE VOLCANIC RIVAL

Is he in heaven? Is he in hell?
That demmed, elusive Pimpernel? 1
Baroness Orczy

In 1972, Peter Vogt, a volcano specialist at the U.S. Naval Research
Laboratory in Washington, D.C., called attention to the huge vol-
canic outpourings that had occurred in India at the time of the K-T
boundary and wondered if the resulting injection of poisonous trace
elements into the atmosphere might not have been the cause of the
mass extinction. 2 Volcanism indeed makes an attractive rival to the
Alvarez theory, as it is the only process other than impact that
meets the dual criteria of being lethal and global. Furthermore, vol-
canoes erupt today and it is easy to project their effects backward
in time. In conformity with Hutton's teachings, present volcanic ac-
tivity might well be the key to past extinction.
In 1978, Dewey McLean of Virginia Tech proposed that the car-
bon dioxide accumulations at the end of the Cretaceous had caused
changes in oceanic circulation and global climate (perhaps a kind of
greenhouse effect) that in turn led to the mass extinction. 3 In 1985,
Officer and Drake adopted and refined these arguments, claiming
that the iridium, shocked minerals, and spherules found at the K-T
boundary are more likely to have been formed by volcanism than
by impact. 4 Although a single volcanic eruption can be almost as
sudden as impact—witness the explosion of Mount St. Helens in
1980—it takes hundreds of such eruptions spread over hundreds of
thousands or millions of years to build up a volcanic cone. If Officer
and Drake are correct that the supposed impact markers can be pro-
duced by volcanism, the alleged spread of the markers for several
meters above and below the K-T boundary would then be naturally

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