Core V34–76, obtained near the summit of a basement ridge in the axis of the Amirante Passage, recovered in-situ pelagic chalk of latest Cretaceous age ( Abathomphalus mayaroensis Zone, ca. 66 Ma). This minimal age for the NNE-trending basement ridges places important constraints on the crustal age of the Amirante Passage region in the western Indian Ocean, and indicates that the Passage has provided a deep-water connection between the Mascarene and Somali Basins throughout the entire Cenozoic.