학술논문

Volcanism and tectonics unveiled in the Comoros Archipelago between Africa and Madagascar
Document Type
article
Source
Comptes Rendus. Géoscience, Vol 354, Iss S2, Pp 7-34 (2022)
Subject
Volcanic province
Active tectonics
Incipient plate boundary
Bathymetry
Backscatter
Northern Mozambique Channel
Comoros Archipelago
Geophysics. Cosmic physics
QC801-809
Chemistry
QD1-999
Geology
QE1-996.5
Language
English
French
ISSN
1778-7025
Abstract
Geophysical and geological data from the North Mozambique Channel acquired during the 2020–2021 SISMAORE oceanographic cruise reveal a corridor of recent volcanic and tectonic features 200 km wide and 600 km long within and north of Comoros Archipelago. Here we identify and describe two major submarine tectono-volcanic fields: the N’Droundé province oriented N160°E north of Grande-Comore Island, and the Mwezi province oriented N130°E north of Anjouan and Mayotte Islands. The presence of popping basaltic rocks sampled in the Mwezi province suggests post-Pleistocene volcanic activity. The geometry and distribution of recent structures observed on the seafloor are consistent with a current regional dextral transtensional context. Their orientations change progressively from west to east (${\sim }$N160°E, ${\sim }$N130°E, ${\sim }$EW). The volcanism in the western part appears to be influenced by the pre-existing structural fabric of the Mesozoic crust. The 200 km-wide and 600 km-long tectono-volcanic corridor underlines the incipient Somalia–Lwandle dextral lithospheric plate boundary between the East-African Rift System and Madagascar.