why does magma form at divergent boundaries
Friction between these plates causes heat that â¦ creates magmas. At a divergent boundary upwelling mantle (athenosphere) decompresses due to reduced pressures, allowing magma to form. This magma is extruded onto the seafloor as pillow basalts, and beneath the seafloors as massive gabbros and sheeted (gabbro) dikes.riction between these plates causes heat that â¦ creates magmas. At a divergent boundary upwelling mantle (athenosphere) decompresses due to reduced pressures, allowing magma to form. This magma is extruded onto the seafloor as pillow basalts, and beneath the seafloors as massive gabbros and sheeted (gabbro) dikes.