Word: novae
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...much happens in Parrsboro, Nova Scotia, population 1800. Until last summer, that is, when two American paleontologists decided to poke around...
Neil H. Shubin, a fourth-year Harvard graduate student in biology, and Paul E. Olsen, a geology professor at Columbia University, had spent a relatively unproductive summer digging at the Nova Scotia site until a misadventure left them trapped by high tide near a cliff on the shore of the Bay of Fundy...
Excavations at the Nova Scotia site have so far yielded more than 100,000 fossilized bone fragments, all dating from shortly after the mass extinction some 200 million years ago that marked the end of the Triassic period and the beginning of the Jurassic. Because of some rapid change, perhaps a catastrophic event, the fossil record shows, 43% of the animal families whose fossilized remains are found in the older Triassic rock are missing from the Jurassic layers just above it. The sudden mass extinction opened the evolutionary way for the proliferation of the dinosaurs and the emergence...
...Triassic-Jurassic extinction, however, that evidence may exist. Less than 500 miles northwest of the Nova Scotia fossil find is the enormous Manicouagan impact crater, its outermost ring--clearly visible in satellite photographs--measuring more than 90 miles in diameter. Given the margins of error in dating, the age of the crater (about 214 million years) makes it suspect in the 200 million-year-old extinction...
Mark Anders, 38, a Berkeley graduate student who works with the Alvarez team, is methodically examining rock samples from the Nova Scotia site, looking for evidence of shocked quartz--grains with their normal crystalline pattern distorted by the kind of shock wave the Manicouagan impact would have produced. If he finds the mineral clues below the fossil deposits, he says, the impact probably preceded and could have caused the extinction, thus strengthening the Alvarez hypothesis...