December 4, 1997. Copyright, 1997, Graphic News. All rights 
reserved

SCIENTISTS MAP CRATER LEFT BY DINOSAURÕS NEMESIS
By Oliver Burkeman

London, December 4, Graphic News: THE METEORITE which may have 
killed off the dinosaurs blew a hole into the surface of the 
earth that covered 45 times the area of Washington DC and was as 
deep as the deepest parts of the Pacific Ocean, scientists have 
concluded.
	Geologists from Cambridge in England began the first detailed 
mapping of the enormous Chicxulub crater Ð now buried 1km beneath 
the Mexican coastline Ð in September 1996. Their results, reached 
in collaboration with an international team led by researchers 
from LondonÕs Imperial College, are published in todayÕs edition 
of the scientific journal ÔNatureÕ. 
The rock, which bored a hole 100km (62.1 miles) wide and 10km 
(6.2 miles) deep, also shot fissures even further into the earth 
when it landed 65 million years ago, reaching below the crust to 
the upper mantle. Objects large enough to cause such devastation 
strike the Earth around once every 100 million years.
But that impact would have been only the first of the dinosaursÕ 
worries, as subsequent earthquakes, fires, tidal waves, noxious 
acid rains and giant dust-clouds would have obliterated land and 
sea life. ÔItÕs almost beyond our comprehension, and seems to 
confirm the story that there was a major catastrophe that swept 
life away,Õ said Dr Dave Snyder, a member of the Cambridge group. 
But according to the findings the crater was smaller than the 
estimates of many scientists, which had been as large as 170km 
(105.6 miles). That suggests a less violent impact than 
previously thought, albeit one still equivalent to 500 million 
Hiroshima-sized nuclear bombs. If the meteorite did annihilate 
all but the most resilient life on earth, the planetÕs biosphere 
may be much more fragile than previously assumed.
The researchers used deep seismic-reflection sounding, steering a 
ship along the coast of the Yucatan peninsula dragging steel 
cylinders which blasted compressed-air explosions towards the sea 
bed. Underwater and onshore ÔhydrophonesÕ monitored the echoes.
ÒMeteorite theoryÕ was first posed as an explanation for the 
dinosaursÕ extinction in 1980, but the existence of the Chicxulub 
crater Ð preserved in pristine condition underneath more recent 
carbonates Ð remained virtually unknown outside the secret files 
of oil companies until 1991.
Many explanations for the disappearance of the dinosaurs have 
been proposed since the first fossilized remains were discovered 
over 150 years ago, including gradual evolution, volcanoes, 
earthquakes, and even, according to some fundamentalist 
Christians, the Great Flood.

/ENDS

Sources: Nature, Cambridge Evening News