The Chagos-Laccadive Ridge and the southern part of the Mascarene Plateau are volcanic traces of the Réunion hotspot.

A huge eruption of this hotspot 65 million years ago is thought to have laid down the Deccan Traps, a vast bed of basalt lava that covers part of central India, and opened a rift which separated India from the Seychelles Plateau.

The Deccan Traps eruption coincided roughly with the nearly antipodal Chicxulub impactor and the Cretaceous–Paleogene extinction of the dinosaurs, and there is considerable speculation that the three events were related.

The Laccadive Islands, the Maldives, and the Chagos Archipelago are atolls resting on former volcanoes created 60–45 million years ago that subsequently submerged below sea level.

The hotspot appears to have been relatively quiet 45–10 million years ago, when activity resumed, creating the Mascarene Islands, which include Mauritius, Réunion, and Rodrigues.