Quartz grains back up meteorite theory?

Press, 13 May 1987, Page 34

Quartz grains back up meteorite theory?

NZPA-AP Washington Bits of quartz found at several sites round the world appear to confirm a theory that the extinction of dinosaurs and other forms of life 65 million years ago resulted from the impact of a large meteorite or comet, scientists say. Researchers from the United States Geological Survey office in Denver, said quartz grains taken from five sites in Europe, as well as New Zealand, the Pacific Basin and elsewhere, have structural features associated with the impact of a large

body striking Earth. Detailed analysis of the mineral debris shows that it comes from a single massive event and not from a series of volcanic eruptions, as other scientists contend, they said in a new report in the journal, “Science.” Bruce Bohor, Peter Modreski and Eugene Foord said the so-called “shocked quartz” is found in the same sediment layers that contain unusually high levels of iridium, a metal common in asteroids, meteors and comets.

The researchers said the latest findings bolster

the disputed, 10-year-old theory of the Nobel Prizewinning physicist, Luis Alvarez, and his geologist son, Walter, that a single catastrophic event led to a great extinction of life on Earth. The Alvarez theory says that impact of an extraterrestrial body 65 million years ago threw up a giant cloud of debris that encircled the globe and diminished sunlight for months, if not years. The climate cooling caused by the dust resulted in the death of dinosaurs and many other types of animal and plant life, it contends.