Newspaper article St Louis Post-Dispatch (MO)

Notebook

Newspaper article St Louis Post-Dispatch (MO)

Notebook

Article excerpt

Death On Ice

Scientists have discovered a "horizon of death" in Antarctica that may reveal direct victims of the catastrophic event 65 million years ago that killed off the dinosaurs and most other species.

The horizon of death, as the researchers call it, is a bed of fish bones covering more than four square miles of Seymour Island near the Antarctic Peninsula. The bed rests directly above a layer of iridium, an element that is rare on Earth but gives a telltale sign of a meteorite impact.

The bed's discovery was reported in November by Purdue University paleontologist William Zinsmeister. He found it during an expedition earlier this year funded by the National Science Foundation.

The horizon of death is a time that scientists call the Cretaceous-Tertiary boundary. It's named for the boundary between two geologic periods. A widely held theory holds that a giant space rock hit the Earth and set off the mass extinction at the time of the boundary.

Scientists can now compare fossils found at the site with those found elsewhere in the world to piece together what caused the mass death. Zinsmeister believes the event may have been more complex than a one-shot execution.

"The fossil record in Antarctica suggests that the final extinction event wasn't immediate, but rather occurred over a period up to 500,000 years," he said. "We actually see a decrease in the global diversity of life starting between 8 million and 10 million years before the impact."

The events at the end of the Cretaceous period probably included climate change, volcanic activity and finally the mega-rock impact or some other equally catastrophic event, he said. William Allen/Post-Dispatch

***** Genetic Link To Smoking

The instinct to smoke may be more fixed in people's genes than the urge to drink heavily.

That's the conclusion of a study by Washington University School of Medicine researchers Andrew Heath and Pamela Madden. The study looked at the life histories of identical and fraternal twins in several countries. …

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