Date: 01-26-91 2:31
From: JOHN KOMAR
Subj: Dinosaurs Wiped out Quickly?
MUFONET-BBS Network - Mutual UFO Network
=START= XMT: 12:02 Wed Dec 05 EXP: 12:00 Wed Dec 12
SCIENTIST SAYS EVIDENCE SHOWS SUPPORT FOR MASS-CATASTROPHE
DEMISE OF DINOSAURS
SAN FRANCISCO (DEC. 5) UPI - New evidence bolsters the view
that dinosaurs and many other life forms suddenly disappeared
65 million years ago after a huge comet or asteroid struck
Earth, a leading scientist says.
The report, presented Tuesday at the annual meeting of the
American Geophysical Union, was sure to rekindle debate on the
controversial topic of how the ancient animals abruptly
More than 2,000 papers have been written on the topic since
Nobel laureate Luis Alvarez and his son, Walter, first
proposed their ''extraterrestial'' theory of dinosaur
extinction in 1980.
In an overview of the latest findings, Walter Alvarez, a
geology professor at the University of California at Berkeley,
said research along an ancient sea floor in southern Spain
showed a species of single- celled marine plankton, called
foramnifera, suddenly became extinct at the end of the
Cretaceous period of history.
Similarly, he said, University of Washington scientists have
found many species of mollusks died out precisely at the end
of the Cretaceous period - about 65 million years ago.
And, new studies of dinosaur fossils in Montana has shown an
extinction pattern ''consistent with a catastrophic
extinction,'' rather than a gradual decline, Alvarez said.
Studies have shown as many as 75 percent of all life forms on
Earth perished at that time, he said.
However, University of Colorado researchers recently reported
the discovery of two sets of dinosaur fossils in Wyoming that
they say are at odds the sudden extinction theory. Robert
Bakker and his colleagues said the dinosaurs appear to have
lived 1 million years after their species were thought to have
''Every major extinction of dinosaurs occurred in a series of
pulses, '' said Bakker, who argues the mass-catastrophe theory
of dinosaur extinction ''is simply not true.''
But Alvarez told the 3,000 scientists attending the geology
meeting that there is evidence that at least two large
extraterrestrial objects struck what is now North America
about the time the many life forms died 65 million years ago.
One crater, discovered in Iowa, dates to the end of the
Cretaceous era. Crystals dating to the same period have been
found a similar crater, 100 kilometers in diameter, on
Mexico's Yucatan Peninsula.
Other scientists believe they have found evidence of a giant
asteroid or comet striking Earth at two sites in the Caribbean
Scientists have calculated that an object with a diameter of 6
miles, falling at 12 miles per second, would have the impact
of a 70 million megaton bomb.
Alvarez cited a recent University of Chicago study that
indicates the impact of such a comet-like object would trigger
winds up to 300 miles an hours, tidal waves that run for
hours, increased global darkness withcold temporatures for
months, and acid and toxic chemical rain for years to decades.
''At first, our critics challenged the impact theory by asking
how a comet impact could wipe out as many species as the
geological record shows,'' Alvarez said. ''Now they are asking
how any species could survive.''