(Phys.org) -- For years, geoscientists have known that a volcano erupted sometime in the mid thirteenth century, with nearly unprecedented force. Skies were darkened and the entire planet experienced a temporary cooling. Whats not been known though, is which volcano it was and the exact year that it blew. Scientists have informally agreed that the event likely occurred in the year 1258. Now however geoscientist Franck Lavigne of Panthéon-Sorbonne University, is claiming that he has proof that the volcano actually erupted a year earlier than that, and whats more, he says, he knows which volcano it was, but wont say until his paper has been published in an as yet still unnamed journal.
Scientists can pinpoint volcanic activity by looking at ice sample taken from the polar regions and tree rings that reflect a cold period of activity. The blast that occurred in the thirteenth century has been the object of much attention because of the enormous amount of sulfur found in such ice samples. So much so that some suggest that it was the biggest blast in seven thousand years. They give it a seven out of eight on the volcanic explosiveness scale. Up until now there has been a list of leading candidates for the volcano most likely to have caused such a massive outburst, but no real evidence to point to any of them as the true culprit.
Lavigne, speaking at the American Geophysical Union conference this year, showed pictures of parts of the volcano he says is the one responsible for the blast and instead of giving its actual name or even general location, showed the evidence hed collected that he says proves its the one that blew back in 1257. Most of those in attendance at the meeting agreed that the pictures he showed depicted a volcano in Indonesia, which would narrow it down some, but not all that much because Indonesia has 130 active volcanoes. Lavignes proof came in the form of the results of analyses of rocks that had been taken from the mystery volcano, which apparently show a nearly exact chemical match with the polar ice samples.
Unfortunately, not much more will be known about the identity of the volcano until Lavignes paper is published and even then, more research by others will have to be done before the research community reaches a consensus on Lavignes claims; either accepting them as likely the truth about what happened or simply adding his ideas to the list of speculative theories.
Explore further: NASA ocean data shows 'climate dance' of plankton
More information: Franck Lavigne: The 1258 Mystery Eruption: Environmental Effects, Time of Occurrence and Volcanic Source, AGU Chapman Conference on Volcanism and the Atmosphere, Selfoss, Iceland, 1015 June 2012.