I attended a seminar in 1987 where we were told that ash from Thera had been found in the Greenland ice cap and that the ice core yielded a date of 1628 B.C. (or perhaps it was “about 1625” and I got the 1628 date later). It wasn’t from carbon dating and it definitely was much longer than 10 years ago. I know they used to date the eruption rather later than that.
Some of the supereruption zealots claimed to have found traces of the Thera eruption in three separate ice cores from Greenland, but that all of them were nearly a century older (which should have red-flagged their attention, but again, they were supereruption zealots). And the ice core evidence matches Aniakchak, an Alaskan volcano.
http://www.informath.org/apprise/a4128/b42008.pdf
http://www.freerepublic.com/focus/news/1623102/replies?c=12
http://www.freerepublic.com/focus/chat/3058727/posts?page=2#2