Around 252 million years ago
more than 96 percent of marine
species and 70 percent of land
species disappeared in a
geological instant. This event
the so-called end-Permian mass
extinction or more commonly
known as, "The Great Dying"
remains the most severe
extinction event in Earth's
history, but its direct cause
has remained a mystery.
Scientists suspect massive
volcanic activity in an area of
Russia called The Siberian Traps
may have had a role in the
Great Dying by raising the air
and sea temperatures and
releasing toxic amounts of
greenhouse gases into the
atmosphere of a very short
period of time. However, until
now, scientists could not
pinpoint when exactly the mass
extinction and eruptions happened
in relation to each other.
MIT researchers have now
determined the Siberian Traps
erupted at the right time and
for the right duration to have
been a likely trigger for the
end-Permian extinction.
By determining the age of rocks
in the region the team came up
with an exact timeline for the
start and end of the eruptions.
They found that the Siberian
Traps began to erupt around
300 thousand years before the
start of the extinction.
These initial eruptions were
followed by massive outpourings
of lava covering a region as
large as the United States. This
area likely kept erupting in
fits and starts finally petering
out about 500 thousand years
after the extinction's end.
While the Siberian Traps has
long been a suspected cause of
the end-Permian extinction the
team says its new timeline is
in essence a smoking gun,
placing the eruptions in the
right place and time to have
been the extinction's main
trigger. Next, the team hopes
to determine the exact tempo of
eruptions, to perhaps identify
a tipping point int he planet's
climate leading up to the
mass extinction.