sentence: New magma emerges onto the ocean floor near the ridge axis.
sentences_before: The Mid-Atlantic Ridge includes a deep rift valley which runs along the middle of the ridge along almost its entire length. At the rift, the boundary between tectonic plates, magma from the mantle reaches the seafloor.
sentences_after: The crystallized magma forms new crust of basalt and gabbro.
concept_name: new magma
headings: Mid-Atlantic Ridge
categories: Atlantic Ocean Plate tectonics Geography of Iceland