From orogenesis to passive margin-the cooling history of the Bemarivo Belt (N Madagascar), a multi-thermochronometer approach

Geodynamic processes, like amalgamation and continental dispersal, control the thermobarometric history of the Earth's crust. Due to its central position, Madagascar is the ideal location for studying important aspects of the amalgamation and breakup of the Gondwana supercontinent. Using geochronological methods (e. g. U-Pb zircon and monazite as well as titanite and apatite fission-track dating), a detailed cooling path for the Bemarivo Belt of northern Madagascar has been deciphered. New SHRIMP zircon ages of ca. 540 Ma and published monazite ages of ca. 515 Ma allow to estimate the duration of the high/ultrahigh-temperature metamorphism related to the early Palaeozoic continental collision during Gondwana formation. The breakup of this supercontinent was associated with crustal thinning, brittle deformation and denudation along the evolving sedimentary basins recorded by the titanite and apatite fission-track ages ranging between ca. 320 Ma and 160 Ma.