Mafic lava is a type of lava that is rich in magnesium and iron, typically forming basaltic rocks. It is relatively low in silica, which makes it less viscous and allows it to flow more easily than felsic lava. Mafic lava is significant in the formation of oceanic crust, volcanic islands, and large igneous provinces.
Source Best, M. G. (2003). “Igneous and Metamorphic Petrology.” Wiley-Blackwell.