undationn.
a. A waving; an undulation. Obsolete. rare except in b.
ΘΚΠ
the world > the earth > water > flow or flowing > wave > movement of waves > [noun]
waving1571
exundation1577
fluctuation1646
exundancea1654
undation1656
exundancy1686
wave-action1880
1656 T. Blount Glossographia Undation, a flowing or rising of waves.
1668 N. Culpeper & A. Cole tr. T. Bartholin Anat. (new ed.) ii. vi. 101 A certain Undation or waving towards one side according to the carriage of the right Ventricle.
b. undation theory n. [translating Dutch undatietheorie (1932)] Geology the theory that selective internal heating of the earth's mantle causes large wave-like folds to appear in the crust.
ΘΚΠ
the world > the earth > earth sciences > theory of formation of earth > [noun] > internal heat
volcanism1811
vulcanism1819
plutonism1842
undation theory1932
magmatism1948
1932 R. W. van Bemmelen in Natuurk. Tijdschr. Nederlandsch. Indië XCII. 93 The geologic history of the western part of the Sunda arc has been examined according to the Undation Theory.
1950 P. H. Kuenen Marine Geol. ii. 146 In his undation theory, van Bemmelen (1939) postulates a primary salsima layer formerly enveloping the whole earth and now forming the floor of the oceans.
1975 Nature 3 Apr. 386/1 The..hypothesis bears some resemblance to the minority view of Van Bemmelen..and others, whose ‘undation theory’ proposes that selective high radioactive heating in the mantle produces warping of the overlying crust followed by lateral spreading under gravity.
This entry has not yet been fully updated (first published 1921; most recently modified version published online June 2019).
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