- The popular belief that a vast crater near Mexico is
the scar left by an asteroid which wiped out dinosaurs 65 million years
ago is questioned today. Fantasy Golf
-
- The Chicxulub crater on the Yucatan Peninsula led many
scientists to conclude that fast-moving debris from the asteroid's impact
would have superheated the atmosphere so that vegetation burst into flames
over much of the planet.
-
- According to this theory, ground temperatures soared
to about 1,000C, igniting forest fires across the world and boiling land
organisms alive. The soot and smoke thrown into the atmosphere may have
helped block sunlight, causing global cooling and plunging the planet into
winter.
-
- But a study published today in the Proceedings of the
National Academy of Sciences, by Dr Gerta Keller of Princeton University,
Dr Thierry Adatte from the University of Neuchatel and Dr Wolfgang Stinnesbeck
from the University of Karlsruhe, suggests the crater predates the mass
extinction by 300,000 years.
-
- Their conclusion came after they studied strata in a
core drilled from the crater.
-
- The team suggests a more complex series of events such
as an additional asteroid impact, perhaps in the Shiva Crater in India,
volcanism, and climate change.
-
- © Copyright of Telegraph Group Limited 2004.
-
- http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2004/03/02/
wdino02.xml&sSheet=/news/2004/03/02/ixworld.html
|
