Joint inversion of gravity and seismic data along the CMD01 profile on the southwestern margin of Madagascar and analysis of crustal structure

The paper is based on the actual gravity, magnetic, and two-dimensional multi-channel seismic profiles obtained during the 2021 Sino-Malagasy international cooperative survey. Through the joint inversion of gravity and seismic data along the CMD01 profile, which traverses the southwest margin of Madagascar, combined with the interpretation and analysis of seismic profiles, the crustal structure, tectonic units, and evolution of the southwestern margin of Madagascar are studied. The main achievement is the establishment of a crustal density model for the southwestern margin of Madagascar, revealing thinned continental crust and the presence of magmatic underplating in certain segments. From land to sea, structural units such as thinned continental crust, continental-ocean transition zone, and oceanic crust domain can be delineated. Due to the influence of Davie Fracture Zone, the continental-ocean transition zone exhibits typical characteristics of a transform-type margin. Combining plate reconstruction and comparative analysis with the northern conjugate margin of Mozambique, the developmental evolution of the southwestern margin of Madagascar is reconstructed. This study has significant theoretical implications for deepening the understanding of the rifting and separation of the Gondwana continent, the developmental evolution of the East African passive margin, and maritime delineation.