plutonism

• Plutonism

Pluto +‎ -ism, after the classical ruler of the underworld.

plutonism (countable and uncountable, plural plutonisms)

1. The old geological theory that the rocks forming the Earth were formed in fire by volcanic activity, with a continuing gradual process of weathering and erosion, then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again.

• vulcanism

• Neptunism

• Plutonist

From French plutonisme.

plutonism n (uncountable)

1. plutonism