In volcanology, a pyroclastic shield or ignimbrite shield is an uncommon type of shield volcano. Unlike most shield volcanoes, pyroclastic shields are formed mostly of pyroclastic and highly explosive eruptions rather than relatively fluid basalticlava issuing from vents or fissures on the surface of the volcano. They typically display low-angle flank slopes and have little or no central collapse, although a shallow sag in the shield is commonly observed. Lava is commonly extruded after explosive activity has ended. The paucity of associated Plinian fall deposits indicates that pyroclastic shields are characterized by low Plinian columns.