Submarine morphology of the Comoros volcanic archipelago

A. Tzevahirtzian , S. Zaragosi , P. Bachèlery (1) , L. Biscara , E. Marchès

1 LMV - Laboratoire Magmas et Volcans

A detailed morpho-bathymetric study of the Comoros archipelago, based on mostly unpublished bathymetric data, provides a first glimpse into the submarine section of these islands. It offers a complete view of the distribution of volcanic structures around the archipelago, allowing to discuss the origin and evolution of this volcanism. Numerous volcanic cones and erosional-depositional features have been recognized throughout the archipelago. The magmatic supply is focused below one or several volcanoes for each island, but is also controlled by lithospheric fractures evidenced by volcanic ridges, oriented along the supposed Lwandle-Somali plate boundary. Massive mass-wasting morphologies also mark the submarine flanks of each island. Finally, the submarine geomorphological analysis made possible to propose a new scheme for the succession of the island's growth, diverging from the east-west evolution previously described in the literature.

Mots clés: Comoros archipelago; Morpho-bathymetry; Submarine volcanism; Volcanic ridges; Volcanic cones; Mounds; Mass slope instabilities

Domaines: Pétrographie; Volcanologie

A. Tzevahirtzian, S. Zaragosi, P. Bachèlery, L. Biscara, E. Marchès. Submarine morphology of the Comoros volcanic archipelago. Marine Geology, 2021, 432, pp.106383. ⟨10.1016/j.margeo.2020.106383⟩. ⟨hal-03101352⟩