New evidence supports a theory that a comet slammed into southern Nevada some 370 million years ago and may have been the first of a series of strikes that triggered a mass extinction of many forms of life, a government geologist said Monday.
The findings were detailed at a meeting of the Geological Society of America.
Geologists Charles Sandberg of the U.S. Geological Survey, John Warme of the Colorado School of Mines and Jared Morrow of the University of Colorado studied evidence of the comet that hit roughly 130 miles northwest of Las Vegas when the region was covered by ocean.
The comet was two-thirds of a mile wide and blasted a 120-mile-wide crater on the sea floor, ripping apart a reef on what was then the Continental Shelf and creating 1,000-foot-high waves that carried half-mile-wide pieces of reef over much of southern Nevada, Sandberg said.
The crash happened 3 million years before one of the five greatest extinctions of life in Earth's history occurred at the end of the Devonian Period, when most organisms lived in the ocean, the researchers said.