Dec. 12, 2008 -- It was a dying on a scale never seen before or since on Earth. The slaughter was everywhere; the fertile ocean and balmy supercontinent Pangea were transformed into killing fields, littered with the bodies of ancient animals. By the time the dust had settled on the Permian-Triassic mass extinction 250 million years ago, 90 percent of life on the planet had been snuffed out. Now a new theory suggests the catastrophe was set in motion 15 million years earlier, deep in the Earth. On the edge of the molten outer core, a plume of super-hot material began rising through the mantle, upsetting convection in the core and throwing the planet's magnetic field into disarray. The weakening of Earth's magnetic field exposed the surface to a shower of cosmic radiation, says Yukio Isozaki of the University of Tokyo. He believes the radiation broke nitrogen in the atmosphere into ions that acted as seeds for clouds enshrouding the planet. Related Content: Project Earth Treehugger.com: Science and Technology HowStuffWorks.com: Volcanoes, Asteroids, Acid and Mass Extinctions "This would've caused severe cooling and a drop in sea level" as the cool temperatures allowed massive ice sheets to accumulate on the continents, Isozaki said. "If you check the rock record at that time, tropical coral reefs die first. Then you start to see fauna from mid latitudes move into the tropics. It all points to cooling." The superplume disrupted the magnetic field and put a strain on creatures living on the surface, but it was only the beginning. Five million years later it reached the surface, Isozaki said, and the hot material punched through the crust, erupting as three successive supervolcanoes. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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