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a theory popular in the late 18th and early 19th centuries assigning a major role to internal forces in the geological history of the earth.
Plutonism, as a definite system of views, was introduced by J. Hutton (1788, 1795). According to Hutton, external forces, such as water and organisms, help to alter the relief, breaking down rock and accumulating as stratified sediments on the sea bottom. The marine sediments, in sinking into the deeper zones of the earth’s crust, are crystallized and compacted, collected into folds, and broken by faults. This is followed by convulsive uplifting, usually accompanied by the intrusion of molten masses that harden to form igneous rock (granites).
Having returned to the surface, the rock is again subjected to decomposition and redeposition, and the circulation of matter commences again. Thus, the plutonism of Hutton was an important component in the hypothesis of the cyclical change in the earth’s crust. This hypothesis derived from Hutton’s one-sided notion of the constancy of geological forces in terms of their type, speed of action, and strength of manifestation.
Plutonism was in direct opposition to neptunism, which rejected any significance of internal geological factors. In the early 19th century, the volcanic origin of basalts was proved, as was the role of the internal energy of the earth in volcanic processes and earthquakes. These developments contributed to the general rejection of neptunism. Some members of the plutonist school ascribed decisive significance to volcanic phenomena in the history of the earth’s surface, as did such representatives of the school of volcanism and catastrophism as A. von Humboldt and L. von Buch. The volcanists and plutonists maintained views that differed significantly, but they were united in their recognition of the major role of the inner forces in the earth’s history. This conclusion remains valid up to the present.
REFERENCESBelousov, V. V. “‘Teoriia Zemli’ Dzhemsa Gettona (k 150-letiiu so dnia opublikovaniia).” Priroda, 1938, nos. 7–8.
Tikhomirov, V. V., and V. E. Khain. Kratkii ocherk istorii geologii Moscow, 1956.
A. I. RAVIKOVICH