Guadalupian (Middle Permian) megaspores from a permineralised peat in the Bainmedart Coal Measures, Prince Charles Mountains, Antarctica

► Three megaspore species are identified from the Permian of Antarctica. ► The first X-ray tomography of Gondwanan megaspores is made. ► A model of silicification based on lake water alkalinity is proposed. ► Palaeogeography linking Indian Mahanadi Graben to Antarctic Lambert Graben supported.