Post by auntym on Jun 13, 2012 15:13:51 GMT -6
www.astrobio.net/pressrelease/4822/new-evidence-links-cosmic-impact-to-mass-extinction
Posted: 06/13/12
New Evidence Links Cosmic Impact to Mass Extinction[/color]
Source: University of California - Santa Barbara press release
Meteorites, Comets and Asteroids
Posted: 06/13/12
Summary: Melt-glass material in a thin layer of sedimentary rock, which dates back nearly 13,000 years, may suggest that an impact was linked to the extinction of North America's megafauna.
An 18-member international team of researchers that includes James Kennett, professor of earth science at UC Santa Barbara, has discovered melt-glass material in a thin layer of sedimentary rock in Pennsylvania, South Carolina, and Syria. According to the researchers, the material –– which dates back nearly 13,000 years –– was formed at temperatures of 1,700 to 2,200 degrees Celsius (3,100 to 3,600 degrees Fahrenheit), and is the result of a cosmic body impacting Earth.
These new data are the latest to strongly support the controversial Younger Dryas Boundary (YDB) hypothesis, which proposes that a cosmic impact occurred 12,900 years ago at the onset of an unusual cold climatic period called the Younger Dryas. This episode occurred at or close to the time of major extinction of the North American megafauna, including mammoths and giant ground sloths; and the disappearance of the prehistoric and widely distributed Clovis culture. The researchers' findings appear in the Proceedings of the National Academy of Sciences (PNAS).
"These scientists have identified three contemporaneous levels more than 12,000 years ago, on two continents yielding siliceous scoria-like objects (SLO's)," said H. Richard Lane, program director of National Science Foundation's Division of Earth Sciences, which funded the research. "SLO's are indicative of high-energy cosmic airbursts/impacts, bolstering the contention that these events induced the beginning of the Younger Dryas. That time was a major departure in biotic, human and climate history."
CONTINUE READING: www.astrobio.net/pressrelease/4822/new-evidence-links-cosmic-impact-to-mass-extinction
Posted: 06/13/12
New Evidence Links Cosmic Impact to Mass Extinction[/color]
Source: University of California - Santa Barbara press release
Meteorites, Comets and Asteroids
Posted: 06/13/12
Summary: Melt-glass material in a thin layer of sedimentary rock, which dates back nearly 13,000 years, may suggest that an impact was linked to the extinction of North America's megafauna.
An 18-member international team of researchers that includes James Kennett, professor of earth science at UC Santa Barbara, has discovered melt-glass material in a thin layer of sedimentary rock in Pennsylvania, South Carolina, and Syria. According to the researchers, the material –– which dates back nearly 13,000 years –– was formed at temperatures of 1,700 to 2,200 degrees Celsius (3,100 to 3,600 degrees Fahrenheit), and is the result of a cosmic body impacting Earth.
These new data are the latest to strongly support the controversial Younger Dryas Boundary (YDB) hypothesis, which proposes that a cosmic impact occurred 12,900 years ago at the onset of an unusual cold climatic period called the Younger Dryas. This episode occurred at or close to the time of major extinction of the North American megafauna, including mammoths and giant ground sloths; and the disappearance of the prehistoric and widely distributed Clovis culture. The researchers' findings appear in the Proceedings of the National Academy of Sciences (PNAS).
"These scientists have identified three contemporaneous levels more than 12,000 years ago, on two continents yielding siliceous scoria-like objects (SLO's)," said H. Richard Lane, program director of National Science Foundation's Division of Earth Sciences, which funded the research. "SLO's are indicative of high-energy cosmic airbursts/impacts, bolstering the contention that these events induced the beginning of the Younger Dryas. That time was a major departure in biotic, human and climate history."
CONTINUE READING: www.astrobio.net/pressrelease/4822/new-evidence-links-cosmic-impact-to-mass-extinction