Irish Sea linked to birth of dinosaurs
FORGET Jurassic Park — scientists have discovered dinosaurs could
have been born in the Irish Sea.
Researchers have found a meteorite that hit the Irish Sea left a crater
the size of Surrey and may have helped giant dinosaurs come to dominate
the planet.
The researchers, who have analysed rock formations in the British Isles
and France, believe the impact caused a tsunami that swamped large parts
of Europe. Most of Britain and Ireland would have been under water when
the meteor hit more than 200million years ago.
It has long been argued that the extinction of the dinosaurs 65million
years ago was caused by a massive asteroid strike.
But scientists have often wondered why dinosaurs, which had previously
been relatively puny, began to develop into giants such as Tyrannosaurus
Rex about 200million years ago.
One theory is that increases in carbon dioxide in the atmosphere led to
bigger plants, which encouraged the development of larger herbivores and
a growth in the size of predators.
Other scientists claim an impact by a meteor may account for the relative
suddenness of the change.
Michael Simms, curator of paleontology at the Ulster Museum in Belfast
who lead the research said: “There was a relatively sudden increase
in the size of dinosaurs around the time we have dated this impact.
“There were a lot of animals in decline, a lot of volcanic activity
and changes in sea levels. This impact may well have been a factor in
the changes.”
Mr Simms’ team found evidence of the shock, probably caused by a
meteorite up to two miles wide and which struck at 18,000mph, in data
from boreholes and rock formations.
Although they have not found the crater they believe the impact may have
been in St. George’s Channel, between Pembrokeshire and the Irish
coast. The crater may have been more than 30 miles wide but would now
be deeply buried beneath the sea floor.
Mr Simms looked for signs of impact rippling out from the crater in sediment
that would have been affected by the shockwave. He found the same unique
pattern at every site he studied, from Northern Ireland to Yorkshire and
Dorset.
“When this impact happened, layers of sand and mud on the shallow
sea floor were violently shaken,” said Mr Simms.
“The shockwave released vast amounts of energy in a short time,
much more than a normal earthquake. The only way this could happen was
to have something hit the Earth at high speed.”
Paul Barrett, a paleontologist at the Natural History Museum in London,
said Mr Simms’ theory was “an interesting idea”.
“This is the first geological suggestion that there was an impact
at this time. What we really want to back this up is a crater of the right
age.”
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