Plu*ton"ic (?), a. [Cf. F. plutonique. See Pluto.]
Of or pertaining to Pluto; Plutonian; hence, pertaining to the interior of the earth; subterranean.
Of, pertaining to, or designating, the system of the Plutonists; igneous; as, the Plutonic theory.
Plutonic action Geol., the influence of volcanic heat and other subterranean forces under pressure. -- Plutonic rocks Geol., granite, porphyry, and some other igneous rocks, supposed to have consolidated from a melted state at a great depth from the surface. Cf. Intrusive rocks, under Intrusive. -- Plutonic theory. Geol. See Plutonism.
© Webster 1913.