The final event during the Pliocene marks the youngest phase of tectonic activity in the Adare Basin. Igneous material penetrated the sedimentary stratigraphy to create volcanic cones which protrude from the sediment stratigraphy, as well as subhorizontal and saucer-shaped sills interrupting the stratigraphy. 257 different volcanic features have been mapped in the basin, partially covered by additional sediment. Geochemical analyses of the Pliocene basalts and the southwest–northeast trending spatial distribution of volcanic centers within and outside the Adare Basin indicate a relation to the Miocene volcanic activity found on land southwest of the basin. Steep normal faults produced prominent seafloor scarps but resulted in only a minor extensional component. At this stage, in terms of horizontal motion, the Adare Basin is nearly locked.
