Geology
About 400 million years ago part of Gondwana, which broke from what is now Africa and drifted westwards relative to Africa. During the mid-Jurassic period (about 170 million years ago) the land fragment that was to become East Falklands and the land fragment that was to become West Falklands rotated about 120° relative to each other. As a result, the fold lines in West Falkland run almost north-west to south-east, parallel to the Sound.
Those in the northern part of East Falkland run east-west, forming the eastern part of northern entrance to the Sound and bordering on the northern banks of San Carlos Water. The boundary between these two land fragments, the Falkland Sound Fault, lies close to and parallel with the western shore of the Sound. Lafonia, which is a much newer formation, has no folds.
Read more about this topic: Falkland Sound