Figure 2. Volcanic breccia. Notice the angular rock fragments
that comprise this rock. Many of the fragments consist of flow-banded rhyolite like the rock shown in Figure 1. Volcanic breccias are formed in explosive volcanic eruptions during which lava and solid rocks of the volcanic vent are blown apart into fragments of different sizes. Some of the rock fragments in the photo are several inches across and are too big too have been thrown very far from the volcanic vent.
Last updated on October 6, 2005