[UP- 2.] The action of thrusting or fact of being thrust upwards, esp. by volcanic action.
1846. Mem. Geol. Surv. Gt. Britain, I. 223. The upthrust of the Cornish and Devonian granites.
1862. G. P. Scrope, Volcanos, 129. Serpentine and even granite may be … in course of formation and upthrust … at the present day.
1895. Pop. Sci. Monthly, March, 580. A crater of this sort is formed by the upthrust of the masses of lava.
