Complex sentence: The South Sandwich Islands are the type example of a primitive oceanic island-arc; a lava specimen from Cook Island, South Sandwich Islands was the nearest terrestrial equivalent to some of the boulders analysed during the Pathfinder mission to Mars (late 1990s).
Split into simpler sentences: The South Sandwich Islands are the type example of a primitive oceanic island-arc. A lava specimen from Cook Island, South Sandwich Islands was the nearest terrestrial equivalent to some of the boulders analysed during the Pathfinder mission to Mars (late 1990s).