ABSTRACTThe Amirante ridge/trough complex developed along the Late Cretaceous transform boundary that separated the Seychelles/India and Madagascar/Somali Basin plates. Motion between these plates was complex, comprising sinistral N‐S strike‐slip movement coupled and coeval with counter‐clockwise rotation induced when seafloor spreading developed in only the southern portion of the transform. The overall morphology of the complex comprises a series of arcuate ridge and trough segments. These segments were successively produced by tectonic and volcanic activity within the zone of migrating plate contact adjacent to the rotational pivot where compression was replaced by extension along the transform boundary. In the extensional regime to the south of this contact zone the Mascarene oceanic basin developed, whilst in the compressional zone further north island arcs developed and the ophiolites of Baluchistan were obducted from the Somali Basin onto the leading edge of the Seychelles/India