I just ran across this. Can any of you guys tell me more about it?
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Update on the possible Falkland craters.
In his book "Rogue asteroids and doomsday comets" Duncan Steel refers to investigations by Michael Rampino (then at the Goddard Institute of Space Studies): "The appropriate antipodal point to Siberia (Siberian Traps 250Ma) is the Falkland plateau off Tierra del Fuego... on that plateau Rampino has identified two sub-oceanic circular basins with diameters of about 300km and 200km respectively. Dating the rocks indicates the same age as the Late Permian Extinction." He cites a Rampino paper in the book "Hazards due to Comets and Asteroids" called "Extraterrestrial impacts and mass extinctions" - this may contain more information.
(2) POSSIBLE FALKLAND IMPACT STRUCTURE "There is a large, circular gravity anomaly on the Falkland Plateau that resembles anomalies associated with large impact craters. It is quite large; greater than 200 km in diameter."