Roland Schlich is one of the pioneers who sailed and explored the structure, age, and evolution of the Indian Ocean from the sixties to the early nineties, at a time when GPS and satellite altimetry were not available, even in dreams. In recognition to his achievements, we propose a session dedicated to geophysical, geological or geochemical studies of the mid-ocean ridges, the adjacent oceanic basins, the numerous hotspots and associated aseismic ridges and plateaus, and more generally the geodynamics and plate tectonic history of the Indian Ocean. We particularly encourage papers presenting the outcome of recent seagoing expeditions.