Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, May 20, 1990 TAG: 9005200048
SECTION: NATIONAL/INTERNATIONAL PAGE: A5 EDITION: METRO
SOURCE: Associated Press
DATELINE: MIAMI LENGTH: Medium
If they can overcome diplomatic hurdles caused by the U.S. economic embargo, Bruce Bohor of the U.S. Geological Survey in Denver and geophysicist Russell Seitz, a former Harvard visiting scholar, want to go to the island to confirm their theory.
"The very presence of Cuba itself may be due to the asteroid," Bohor said in a telephone interview last week. "The curved tip of western Cuba may be the crater rim, and the Isle of Pines could be the central uplift," or peak.
Clues pointing to a Caribbean landfall were assembled slowly in the decade since scientists first advanced the idea of a catastrophic end to the dinosaurs. Although the asteroid theory is not universally accepted - some paleontologists blame climate changes or disease for the dinosaurs' extinction - it now has widespread support.
The theory requires an asteroid about 6 miles in diameter gouging out a crater up to 150 miles wide. The resulting dust cloud, or perhaps impact-spawned fires, volcanic activity, climatic shifts and other factors, could have killed the giant reptiles directly or choked off their food supply.
"But there was a tough time accepting this because there was no crater to relate it to - so we had to find a crater," Bohor said. "The possibility was that it hit in the ocean, but that was hard to determine."
Researchers, however, began to notice what is in effect a geological directional arrow pointing to somewhere near North America.
A study by Arizona researchers Alan Holdebrand and William Boynton, published in Friday's Science magazine, agrees about the general area of the strike, somewhere in the Caribbean. They believe the asteroid fell more to the south of what is now Cuba, however - closer to Colombia.
Bohor and Seitz, who explained their theory in the April 12 edition of Nature, say without a close inspection of the Cuban site, no one can be sure. And, they say, all geologists are basing their findings on the same data.
As geologists, Bohor and Seitz take no position on whether an asteroid killed off the dinosaurs, or even if this impact might be a candidate. Their goal, they say, is simply to determine if there is an impact just south of Cuba's western tip 66 million years ago.
Knowing where the asteroid hit could help solve questions about "nuclear winter," acid rain and previously unexplained evolutionary patterns.
Of most immediate concern, it could give insight into confusing geological plate movements in the Caribbean, they note. Examining the crater could perhaps help determine when and where to expect earthquakes.
by CNB