geosynclinal, a. and n. Geol.
(dʒiːəʊsɪŋˈklaɪnəl)
[f. geo- + synclinal.]
A. adj. Forming a large depression in the surface of the earth, from the lowest point of which there is a gradual rise to either side, even although the continuity of this is broken by smaller depressions. The opposite of geanticlinal.
| 1879 Dana Man. Geol. (ed. 3) 817 Flexure implies both upward and downward bendings, geanticlinal and geosynclinal, the one a complement to the other. 1882 A. H. Green Phys. Geol. xiii. (ed. 3) 630 After the geosynclinal mass had accumulated the state of things stood thus. |
B. n. A geosynclinal dip or depression in the earth's surface.
| 1873 Dana in Amer. Jrnl. Sci. Ser. iii. V. 430 The making of the Alleghany range was carried forward at first through a long-continued subsidence—a geosynclinal (not a true synclinal). 1882 A. H. Green Phys. Geol. xiii. (ed. 3) 629 To the great trough-shaped mass of rock which was thus accumulated Dana has given the name of a Geosynclinal. Ibid. The geosynclinal of a mountain-chain. |