magmatism Geol.
(ˈmægmətɪz(ə)m)
[f. L. magmat-, magma (see magma) + -ism.]
a. The theory advocated by magmatists.
| 1948 Q. Jrnl. Geol. Soc. CIII. 140 Dr. Reynolds ‘tolls the knell’ of the passing theory of ‘magmatism’ as an all-embracing explanation of the origin of all plutonic rocks. Ibid. 141 A new era in petrogeny, an era in which ‘magmatism’ will become incorporated with ‘transformism’, plutonic processes will become closely linked with metamorphic processes, and petrogenesis..will become an integral part of a wider science of geochemistry. |
b. Motion or solidification of magma; magmatic activity.
| 1952 H. Ramberg Orig. Metamorphic & Metasomatic Rocks 3 (heading) Natural boundary between metamorphism and magmatism. 1970 Clifford & Gass Afr. Magmatism & Tectonics p. vii, Studies..to illustrate the relationship between two important geological processes—magmatism and tectonics. 1974 Nature 19 Apr. 650/1 Seismicity, tectonism and magmatism are now concentrated near plate margins. |