Andesite

Main Elements:

Si, Al, Ca, Na, K, Fe, Mg, O

Chemical Composition:

SiO₂ 57-63%, Al₂O₃ 17-20%, CaO 5-8%, Na₂O 3-5%, K₂O 1-3%, FeO 3-5%, MgO 2-4%

Density:

2.5-2.8 g/cm³

Compressive Strength:

50-200 MPa

Melting Point:

950-1100°C

Formation:

Forms from intermediate composition lava flows in subduction zones, typically associated with explosive volcanic eruptions.

Composition:

Composed mainly of plagioclase feldspar and pyroxene, with minor amounts of hornblende and biotite.

Types:

• Hornblende Andesite
• Pyroxene Andesite
• Biotite Andesite

Etymology:

Named after the Andes Mountains in South America, where it is abundant.

Uses:

• Construction aggregate
• Road building
• Decorative stone

Distribution:

Found in subduction zones worldwide, especially the Andes, Cascades, and Japan

Historical Use:

Used by ancient peoples in volcanic regions for tools and construction materials.

Symbolism:

Represents volcanic power and Earth's dynamic processes

Where is andesite found?

Andesite is commonly found in subduction zones, especially in the Andes Mountains, Cascade Range, and volcanic regions of Japan.

How does andesite form?

Andesite forms from intermediate composition lava flows in subduction zones, where oceanic crust melts and mixes with continental crust.