Volcanic Processes and Rock Melting Techniques

Decompression melting

Melting due to pressure reduction in rocks.

Flux melting

Melting caused by the addition of volatiles.

Temperature increase melting

Melting from rising temperatures in rocks.

Felsic magma

High silica content, low density, viscous.

Mafic magma

Low silica content, high density, less viscous.

Composite volcano

Steep-sided, formed from alternating eruptions.

Cinder cone volcano

Small, steep, built from volcanic debris.

Shield volcano

Broad, gentle slopes, formed by low-viscosity lava.

Caldera

Large depression formed after a volcanic eruption.

Pyroclastic flow

Fast-moving current of hot gas and volcanic matter.

A'a lava

Rough, jagged lava flow texture.

Pahoehoe lava

Smooth, ropy lava flow texture.

Pluton

Intrusive igneous rock body formed underground.

Basalt plateaus

Extensive flat areas formed by flood basalts.

Columnar jointing

Geometric patterns formed in cooling lava.