What is the geology of the Réunion hotspot plume?

The Réunion hotspot is a volcanic mantle plume in the Indian Ocean that has been active for over 65 million years. As tectonic plates drift overhead, the hotspot creates extensive volcanic tracks, including the Deccan Traps, the Maldives, and the Mascarene Islands. It currently lies beneath the island of Réunion, home to the highly active Piton de la Fournaise shield volcano.

What we know

• The Réunion hotspot is a volcanic hotspot currently located under the island of Réunion in the Indian Ocean. [1, 2]
• A massive eruption from this hotspot 65 million years ago created the Deccan Traps basalt beds in India and separated India from the Seychelles Plateau. [2, 4]
• As the Indian plate drifted north, the hotspot punched through it to form a chain of volcanic islands and undersea plateaux, including the Laccadive Islands, Maldives, and Chagos Archipelago. [2, 5]
• Basement basalts underlying the Maldives support the hotspot theory by showing a chronological age progression, being younger toward the south. [5]

Still open

• There is speculation about whether the Deccan Traps eruption, the Chicxulub impactor, and the Cretaceous-Paleogene extinction were related.
• Sources slightly differ on the exact timing of the Deccan Traps eruption, citing it as either 65 million years ago or more than 66 million years ago.

Where to go next

• what followedWhat are the Deccan Traps?
• how it workedHow do mantle plumes form hotspots?
• a case in pointWhat is the geology of the Maldives?
• the bigger pictureHow does plate tectonics shape island chains?
• an unexpected connectionWhat caused the Cretaceous-Paleogene extinction?

Sources

• [1]Réunion hotspot (Wikidata Q3393388) · CC0 1.0
• [2]Réunion hotspot · CC BY-SA 4.0
• [3]Hotspot (geology) · CC BY-SA 4.0
• [4]Geology of Réunion · CC BY-SA 4.0
• [5]Geology of the Maldives · CC BY-SA 4.0