BBC News, Jonathan
Amos, Science correspondent, 30 Sep 2013
Related
Stories
 |
| The bowl that is today Segara Anak Crater Lake formed after the eruption |
The mystery
event in 1257 was so large its chemical signature is recorded in the ice of
both the Arctic and the Antarctic.
European
medieval texts talk of a sudden cooling of the climate, and of failed harvests.
In the PNASjournal, an international team points the finger at the Samalas Volcano on
Lombok Island, Indonesia.
Little
remains of the original mountain structure - just a huge crater lake.
The team
has tied sulphur and dust traces in the polar ice to a swathe of data gathered
in the Lombok region itself, including radiocarbon dates, the type and spread
of ejected rock and ash, tree-rings, and even local chronicles that recall the
fall of the Lombok Kingdom sometime in the 13th Century.
"The
evidence is very strong and compelling," Prof Clive Oppenheimer, from
Cambridge University, UK, told the BBC.
Co-worker
Prof Franck Lavigne, from the Pantheon-Sorbonne University, France, added:
"We conducted something similar to a criminal investigation.
"We
didn't know the culprit at first, but we had the time of the murder and the
fingerprints in the form of the geochemistry in the ice cores, and that allowed
us to track down the volcano responsible."
The 1257
eruption has been variously linked with volcanoes in Mexico, Ecuador and New
Zealand.
But these
candidates fail on their dating or geochemistry, the researchers say. Only
Samalas can "tick all the boxes".
Global
event
The team's
studies on Lombok indicate that as much 40 cubic kilometres (10 cubic miles) of
rock and ash could have been hurled from the volcano, and that the finest
material in the eruption plume would likely have climbed 40km (25 miles) or
more into the sky.
It would
have had to be this big in order for material to be carried across the entire
globe in the quantities seen in the Greenland and Antarctic ice layers.
The impact
on the climate would have been significant.
 |
| What are the four ways volcanoes can kill? |
Archaeologists
recently put a date of 1258 on the skeletons of thousands of people who were buried
in mass graves in London.
"We
cannot say for sure these two events are linked but the populations would
definitely have been stressed," Prof Lavigne told BBC News.
In
comparison with recent catastrophic blasts, Samalas was at least as big as
Krakatoa (1883) and Tambora (1815), the researchers believe.
The ice
cores do hold clues to yet another colossal event in about 1809, but, like
Samalas before it, finding the source volcano has been difficult.
Prof
Oppenheimer said: "It's outstanding that we haven't come across evidence
for it. Where in the world could you bury such bad news?"
No comments:
Post a Comment