Here's a breakdown:
* Andesite: This is the most common rock type found in stratovolcanoes. It's an intermediate volcanic rock with a silica content between 52% and 63%. Andesite is typically gray to dark gray in color and has a medium-grained texture.
* Basalt: A darker, more mafic rock with less silica (45% to 52%) than andesite. Basalt is often found in the lower slopes of stratovolcanoes and can form lava flows.
* Dacite: A more felsic rock with higher silica content (63% to 70%) than andesite. Dacite is typically light gray to pink in color and has a fine-grained texture.
* Rhyolite: The most felsic rock type found in stratovolcanoes, with a silica content over 70%. Rhyolite is often light-colored and has a glassy texture.
The specific composition of a stratovolcano can vary depending on factors like the tectonic setting, the source of the magma, and the eruption history. However, andesite is typically the dominant rock type.
It's important to note that stratovolcanoes can also contain other rock types, such as pyroclastic rocks (formed from volcanic ash and debris) and volcanic breccia (a mixture of angular volcanic fragments). These rocks are often found in the upper parts of stratovolcanoes where explosive eruptions have occurred.
