Geologists Find Killer Crater Under Arctic Sea
(From the May/June 1999 issue of StarDate magazine)
An asteroid that struck the Barents Sea off the coast of Norway 150 million years ago may have triggered a global environmental catastrophe, killing entire species of plants and animals. It also created a 25-mile-wide crater, which oil-company geologists discovered only recently. Analysis of rock grains and a radioactive mineral from the seabed late last year confirmed the crater's impact origin.
Scientists have identified about 160 impact craters on Earth, including seven on the ocean floor. One of the largest is Chicxulub, off the eastern coast of Mexico. Many scientists believe that climate changes caused by the Chicxulub impact killed most of the life on Earth, including the dinosaurs.
The Barents Sea crater is much smaller than Chicxulub, so the impact that created it was less powerful. Still, it should have generated a fireball hotter than the surface of the Sun, and created tidal waves that reached from Canada to Russia. It also should have blasted enough material into the atmosphere to black out the Sun, creating a long "global winter." Unable to adapt to such a sudden and dramatic environmental change, many species simply vanished.
Norwegian scientists estimate that an asteroid 1.2 miles (2 km) in diameter gouged the crater when it hit Earth at a speed of about 18,000 miles an hour (30,000 kph). -- — Damond Benningfield
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