Table 1.

A summary of the Neoproterozoic–Ordovician geotectonic evolution of northern-central Madagascar

Approximate date (Ma)Event
500–490Ductile shearing along major shear zones; final metamorphic overprint
530–510End stages of terminal Pan-African thermal anomaly including post-collisional magmatism (e.g. Maevarano Suite plutons)
560–530Terminal Pan-African tectono-thermal events including amalgamation of the Antongil Craton with the already amalgamated Antananarivo and Masora cratons with reactivation of the Manampotsy Belt. Later thrusting of the Bemarivo Belt over the Antongil and Antananarivo cratons and the Anaboriana Belt; the Tsaratanana Complex thrust over both the Antananarivo Craton and the Manampotsy Belt. Initial emplacement of late- to post-tectonic granites including the Maevarano and Ambalavao Suites and Carion Subsuite
630–595Emplacement of the Kiangara Suite of granites into the Antananarivo and Masora cratons and into the Anaboriana and Manampotsy belts
760–715Arc volcanicity and associated sedimentation in the Bemarivo Belt
740Amalgamation of the Antananarivo and Masora cratons and tectonic development of the Manampotsy Belt, possibly during closure of ocean between the Antananarivo and Masora cratons
840–720Sedimentation on the Archaean foundations of the Antananarivo and Masora cratons and on the surrounding continental shelves and offshore arc terranes (Anaboriana and Manampotsy belts). Emplacement of the Imorona–Itsindro Suite magmatic arc and unroofing of these intrusions