Cenozoic Dynamic Topography of Madagascar

It has been proposed that Oligo-Miocene regional uplift of Madagascar was generated and is maintained by mantle dynamical processes. Expressions include flat-lying Upper Cretaceous-Paleogene marine limestones crop out at elevations hundreds meters along the western seaboard emergent Quaternary coral-rich terraces rim coastline. Here, we explore history subcrustal topographic support through a combined analysis four sets observational constraints. First, exploit published receiver function estimates crustal thickness spectral admittance between gravity topography. An value ∼+40 ± 10 mGal km−1 wavelengths >500 km implies ∼1 topography supported Secondly, new apatite fission-track helium measurements from 18 basement samples are inverted, constraining temperature denudation histories. Results suggest 0.5–1.6 occurred after ∼30 Ma. Thirdly, calculate minimizing misfit observed calculated longitudinal river profiles. during Neogene times. Finally, inverse modeling rare earth element concentrations in mafic rocks indicates melting asthenospheric source depths ≤65 with potential temperatures 1300–1370 °C. Melting higher beneath Réunion Island northern lower Comores southern Madagascar. These inferences consistent shear wave velocities obtained tomographic models. We conclude underlain thinned lithospheric thermal anomaly lies within an layer