Andesite
“The subduction zone signature”
Igneous
Andesite is an intermediate volcanic rock named after the Andes Mountains, where it is extremely common. It forms at convergent plate boundaries where oceanic crust subducts beneath continental crust, producing explosive, ash-rich eruptions.
Composition
plagioclase feldspar, pyroxene, hornblende, biotite
Where Found
Andes Mountains, Cascades (USA), Japan, Indonesia, Philippines
Mohs Hardness
6
Fun Fact
Andesite is the most common volcanic rock found at subduction zones and is closely associated with the 'Ring of Fire' around the Pacific Ocean.
Test Your Knowledge
What role does water play in generating andesitic magma at subduction zones?
Related Specimens
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