Volcanism and tectonics unveiled in the Comoros Archipelago between Africa and Madagascar

Abstract

Volcanism and tectonics unveiled in the Comoros Archipelago between Africa and Madagascar Volcanisme et tectonique découverts le long de l'archipel desComores entre l'Afrique et Madagascar

Relative Sea Level and Coastal Vertical Movements in Relation to Volcano-Tectonic Processes at Mayotte Island, Indian Ocean

“…Different loading masses corresponding to various volumes of volcanic rock involved in volcanic edifice building were simulated in models of several volcanic edifices 200 m tall and with diameters of 3.5 km as suggested by bathymetric data [48,49,82], corresponding to a conical volume of 0.6 km 3 and a mass of 1.8 × 10 12 kg. This study discusses the loading mass that explains the observed subsidence.…”

“…New volcanic edifices have been built in the last few thousand years during the sea level rise, including relatively young volcanic features east of Mayotte [1,33,48,49], along the slope of the main structure and volcanic rocks ranging in age from 2.2 to 7.965 kyr [56][57][58]. To our knowledge, there are no published ages for submarine edifices on the Mayotte slope.…”

“…Other researchers have interpreted the E-W seismic alignment in the region as highlighting the activity of structures associated with the continuity of the East African Rift and in relation to the drift of Madagascar on an E-W-trending axis [19,31,45,47]. In detail, the overall E-W trend is associated with a N130 to N160 distribution of seismicity and of the volcanic patterns along the Somali/Lwandle plate right-lateral transform boundary [31,45,48,49].…”

Pliocene-to-Holocene volcano-tectonic activity on Mohéli Island (Comoros archipelago) constrained by new K Ar ages

“…1a) has regained attention from the scientific community since 2018 due to the birth of a fast-building submarine volcanic edifice, 50km east of Mayotte, Fani Maoré volcano (Lemoine et al, 2020;Feuillet et al, 2021;Berthod et al, 2021a). Marine geophysical surveys have since revealed that the archipelago is only the emerged portion of a much wider province of volcanic ridges and seamounts extending north and east of the islands (Tzevahirtzian et al, 2021;Thinon et al, 2022). The origin of volcanism in the Comoros archipelago remains enigmatic in many aspects since none of the proposed interpretations can explain all the observations.…”

Special issue Comptes-Rendus Geoscience: The Mayotte seismo-volcanic crisis of 2018–2021 in the eastern Comoros archipelago (Mozambique channel)

“…Most of these advances are direct outcomes from the ANR COYOTES project (https://anr.fr/Projet-ANR-19-CE31-0018), from oceanic cruises such as SIS-MAORE (doi:10.17600/18001331), and from the now regular MAYOBS surveys (doi:10.18142/291). In Thinon et al [2022] for instance, extension of the submarine volcanism in the northern Mozambique channel is evidenced, and the regional geodynamics is investigated by means of marine geophysics. This first part also questions the nature of the lithosphere beneath the Comoros archipelago, by probing its thermal state from literature and newly published heat flow measurements [Rolandone et al, 2022] and its structure from teleseismic receiver functions [Dofal et al, 2022].…”