Abstract Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa–Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four consist largely of Archaean metamorphic rocks (Antongil, Masora and Antananarivo Cratons, Tsaratanana Complex). The fifth (Bemarivo Belt) comprises Proterozoic meta-igneous rocks. The older rocks were intruded by plutonic suites at c. 1000 Ma, 820–760 Ma, 630–595 Ma and 560–520 Ma. The evolution of the four Archaean domains and their boundaries remains contentious, with two end-member interpretations evaluated: (1) all five crustal domains are separate tectonic elements, juxtaposed along Neoproterozoic sutures and (2) the four Archaean domains are segments of an older Archaean craton, which was sutured against the Bemarivo Belt in the Neoproterozoic. Rodinia fragmented during the early Neoproterozoic with intracratonic rifts that sometimes developed into oceanic basins. Subsequent Mid-Neoproterozoic collision of smaller cratonic blocks was followed by renewed extension and magmatism. The global ‘Terminal Pan-African’ event (560–490 Ma) finally stitched together the Mid-Neoproterozoic cratons to form Gondwana.

Abstract The offshore Majunga basin of Madagascar appears to be the largest salt basin in East Africa. It is the previously very poorly known deep-water part of the Majunga that hosts a variety of salt features, including both autochthonous and allochthonous structures which include toe-thrust anticlines, falling and rising diapirs, turtle structures, salt tongues/canopies and withdrawal mini-basins beneath the slope. In the middle of the salt basin, the salt edge displays a major basinward salient where the Early Jurassic syn-rift salt ramped up through the Jurassic and Cretaceous strata forming a broad allochthonous salt nappe. As only 2D seismic reflection data are available over the Majunga salt basin, it provides only a sub-regional scale example of the interaction between salt and sediments. One of the regional-scale aspects of salt/sediment interaction includes the relative importance of updip sediment loading versus regional tilting of the margin in the initiation of allochthonous salt tectonics. The uplift in the hinterland of the Majunga basin occurs during the mid-Cretaceous when the Seychelles/Indian continent rifted away from the eastern side of Madagascar. It is suggested here that it was the regional basinward tilt that triggered the salt tectonics. Thus, the subsequent Late Cretaceous, accelerated sedimentary influx only has enhanced the ongoing salt deformation.