For one thing, Plato is the only surviving ancient source for the Atlantis legend, and he placed it outside Gibraltar, referred to as the Pillars of Hercules, and explicitly described the Americas as lying beyond Atlantis. There’s nothing in the Atlantis story to suggest any other location. Furthermore, the caldera which is the harbor of the island of Santorini is over 100,000 years old; the only major Theran eruption recorded in ancient sources (and remember, Minoan and Mycenaean societies were literate) dates to circa 200 BC, which is AFTER PLATO and AFTER HERODOTUS (who also writes quite a bit about Santorini / Thera / Calliste). Still furthermore, radiocarbon dates on the island are off by hundreds of years due to the preponderance of C12 in the volcanic soils. Still furthermore, the Greenland ice core data matches an Alaskan volcano, not Thera.
A settlement on the island of Thera was destroyed during the Bronze Age. From ash from that explosion which landed on Greenland, an estimated date of 1628 B.C. was calculated about 20 years ago. The Minoans and Mycenaeans may have been literate, but we have no historical texts from either society. Most of the surviving Linear A and Linear B records are palace records (inventories and the like).
If I remember correctly, Plato was referring to a story by Solon of his talks with an Egyptian priest. The priest said these events were 9,000 years old, and since Solon was before Plato’s time which was around 400 BC, this pretty much adds up to 13,000 years ago which ties in nicely with the possible cometary cause of the Younger Dryas major cooling event. Links anyone?