The Japan Times, March 28, 1997
Scientists say dinosaurs dwindled before asteroid
LONDON (Reuter) A team of London scientists Wednesday officially challenged the popular theory that an asteroid wiped out the dinosaurs 65 million years ago.
The mass extinction had already been underway for several million years when the asteroid smashed into the Earth, they wrote in the Journal of the Geological Society.
According to the 22 experts, led by Norman McLeod of the Natural History Museum, a period of violent volcanic eruptions combined with a big drop in global sea level to weaken the dinosaurs' dominance of the planet.
There is plenty of evidence that an asteroid did smack into the Earth near what is now southern Mexico, sending out huge tidal waves and throwing up a cloud of dust that brought 5,000 years of winter.
"The end-Cretaceous impact event may have contributed to the ... mass extinction in the manner of a coup-de-grace blow to the Earth's environment," they wrote.
"However, the fossil record indicates that most loss in biotic diversity associated with the ... mass extinction had already taken place by the time the asteroid arrived."
McLeod's group's theory is not new and has been argued for some time. But this is an especially large and concerted effort by scientists not only from the museum, but from University College London and Birkbeck College.
They noted sea levels had dropped by about 100 meters and a huge flow of lava had covered what is now the Indian subcontinent -- both of which would have been highly disruptive to climate.