Were the Falkland Islands hit by a giant asteroid 250 million years ago?

A rather startling claim, widely reported in May 2017, located one of the largest asteroid impact craters yet discovered on planet Earth just to the west of the Falkland Islands. Even Penguin News, the Falklands’ very own local newspaper, ran the story under the headline ‘Falkland Basin may be largest impact crater’ (Vol. 28, No. 43 for 12 May 2017, p. 7). In these days of fake news, our first inclination was to suspect that the report might be a hoax, but even though it’s almost certainly not true there is rather more to the story than its improbability might suggest, and its background is worth exploring.