In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.
The stratovolcano is composed mainly of andesite lava flows and breccias and was largely formed prior to the most recent major glaciation (Fraser Glaciation), which occurred between about 25,000 and 10,000 years ago.
The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith.