Lava Sheet

mode of occurrence of lava when it pours out in very large quantities and spreads in all directions during a volcanic eruption. It forms lava plateaus on which younger volcanoes may occur. The amount of lava issued during formation of a lava sheet may be as much as many cubic kilometers. It is thought that such outpourings occur from large fissures or from large openings formed when the roofs of magma chambers founder.