• Pyroclastic rocks form from the lithification of broken fragments of rock from volcanic eruptions.
Pyroclastic texture in a volcanic breccia (Photograph by Parvinder Sethi)
This rock is made up of broken pieces of volcanic material. It is called a volcanic breccia, and is a type of extrusive igneous rock.
• Flood basalts are very large lava flows that come from large fissures or cracks in the earth.
Catoctin Formation, an ancient flood basalt in Virginia (Photograph by Stan Johnson)
The Catoctin Formation, shown here along the Blue Ridge Parkway, is an ancient flood basalt. This basalt flowed over large parts of Virginia about 570 million years ago.