Flow banding
![Flow-banded rhyolite in the Dunn Point Formation (Ordovician) exposed near Arisaig, Nova Scotia.](/Images/godic/202501/13/Flow_banded_rhyolite5515.JPG")
![Flow banding at the rim of a peridotite intrusion. Dark and green pyroxenite bands at the bottom represent the melt, brownish lherzolite bands at the top the solid phase. Near Midsund, Norway, 1 euro coin for scale.](/Images/godic/202501/13/Peroxenite_banding5515.JPG")
Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from the substance molten rock or magma.
Flow banding is caused by friction of the viscous magma that is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or, if the magma is erupted, the surface of the earth across which the lava is flowing.