Major volcanic events from Mohéli, Anjouan and Mayotte Island edification in the Comoros Archipelago at Northern Mozambique Channel inferred by seismic reflection data.

Abstract

The timing of volcanic events at the Comoros archipelago (North Mozambique Channel) are currently only known by dating samples from the onshore islands. According to these data, the oldest lavas from the Comoros are 10 Ma and several distinct volcanic periods are inferred (Michon, 2016). However, the onset of the volcanism within the archipelago cannot be constrained by these data. Here we use two different datasets of wide angle, and  high resolution multichannel seismic reflexion profiles to provide insights on the birth and early evolution of the volcanism around the islands of Mohéli, Anjouan and Mayotte, in the Comoros basin (SISMAORE cruise, ANR COYOTES project, (Thinon et al., 2022)).The seismic interpretation revealed several distinct volcanic horizons within the sedimentary cover, that could be related to the formation of the Jumelles Ridge, Geyser bank, Mohéli, Anjouan and Mayotte volcanic island. We identify the onset of the main volcanic event that led to the formation of Mayotte island. We show that the corresponding seismic volcanic horizon is located at different depths in the north and the south of Mayotte island. This indicates at least two different major volcanic phases of the Mayotte island edification. Seismic profiles also show  the presence of a magmatic feeder complex underneath. Using known regional stratigraphy, we finally propose a chronology of all the volcanic episodes in the regional volcanic context of the construction of the Comoros archipelago.Michon, L., 2016. The Volcanism of the Comoros Archipelago Integrated at a Regional Scale, in: Bachelery, P., Lenat, J.-F., Di Muro, A., Michon, L. (Eds.), Active Volcanoes of the Southwest Indian Ocean, Active Volcanoes of the World. Springer Berlin Heidelberg, Berlin, Heidelberg, pp. 333–344. https://doi.org/10.1007/978-3-642-31395-0_21Thinon, I., Lemoine, A., Leroy, S., Paquet, F., Berthod, C., Zaragosi, S., Famin, V., Feuillet, N., Boymond, P., Masquelet, C., Mercury, N., Rusquet, A., Scalabrin, C., Van der Woerd, J., Bernard, J., Bignon, J., Clouard, V., Doubre, C., Jacques, E., Jorry, S.J., Rolandone, F., Chamot-Rooke, N., Delescluse, M., Franke, D., Watremez, L., Bachèlery, P., Michon, L., Sauter, D., Bujan, S., Canva, A., Dassie, E., Roche, V., Ali, S., Sitti Allaouia, A.H., Deplus, C., Rad, S., Sadeski, L., 2022. Volcanism and tectonics unveiled in the Comoros Archipelago between Africa and Madagascar. Comptes Rendus. Géoscience 354, 1–28. https://doi.org/10.5802/crgeos.159