Amber Listserv / IOL: Volcanoes may have killed off dinosaurs

[JOHN FUDALA]

There we go again...

  Reuters
     March 22 2008 at 10:55AM

Gas-belching volcanoes may be to blame for a series of mass extinctions over
the last 545-million years, including that of the dinosaurs, new evidence
suggested on Thursday.

A series of eruptions that formed the Deccan Traps in what is now India
pumped huge amounts of sulphur into the atmosphere 65-million years ago,
with likely devastating repercussions for the Earth's climate, scientists
said.

Gigantic eruptions, forming so-called "flood basalts", are one of two
leading explanations for a series of mass extinctions that have killed off
species periodically throughout history.

The other theory involves asteroid impacts - generally considered the prime
suspect in the case of the extinction of dinosaurs 65-million years ago.

There have been doubts about the killing power of volcanoes because, until
now, researchers have struggled to measure just how much toxic gas would
have been released.

But after finding rare inclusions of glass in the Deccan rock, a
British-based team has found vital preserved information about its original
gas content. Writing in the journal Science, they concluded that the massive
of amounts of both sulphur and chlorine released would probably have had a
"severe" environmental impact.

The volcanoes may have spewed 10 times as much sulphur into the atmosphere
every year as humans have done recently by burning coal in power stations
and through other industrial activities.

The result would have been widespread acid rain and aerosols of sulphuric
acid in atmosphere, cooling the surface of the Earth and upsetting
circulation patterns.
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