| 释义 |
ˈrifting, vbl. n.2
[f. rift v.1 + -ing1.]
1. Chiefly U.S.
a. Quarrying. The occurrence or development of rifts in rock. Cf. rift n.2 2 f.
18899th Ann. Rep. U.S. Geol. Survey 602 (heading) Rifting of the quarried rocks. 1891Amer. Jrnl. Sci. CXLI. 269 Rifting is..dependent upon the thousands of minute dislocations which occur in every cubic inch of rock. 1937Mem. Geol. Soc. Amer. V. 20 Rifting in granites has been known for a long time.
b. The action of splitting mica into thick sheets.
1939G. A. Roush Strategic Min. Supplies xii. 345 The books [of mica] are first split into slabs about 1/4 inch thick (rifting). 1954S. J. Johnstone Minerals for Chem. & Allied Industries 331 The preparation of mica for the market usually involves..rifting into sheets sufficiently thin to be cut by hand with a blade. 1960S. A. Montague in J. L. Gillson et al. Industr. Min. & Rocks (ed. 3) xxvii. 559/1 The operations of rough splitting and trimming mica are termed ‘rifting’ or ‘sheeting’.
2. Physical Geogr. The process of severing of areas of the earth's crust into distinct blocks or plates by formation of rifts. Cf. rift n.2 2 g.
1924J. G. A. Skerl tr. Wegener's Orig. Continents & Oceans xi. 166 Folding and rifting are only different effects of one and the same process. 1969Times 20 May 12/7 Major rifting of the Earth's surface. 1969Nature 11 Oct. 140/1 Although rifting was completed during the Lower Cretaceous, significant continental drift did not occur until the Lower Turonian. 1978Ibid. 13 July 127/1 The eruptions were accompanied by extensive rifting..which led to formation of the Sveinagjá graben.
fig.1975W. Safire Before the Fall x. iv. 667 There was no rift..between the President and his national security adviser. There was plenty of rifting going on between Henry and the White House staff. |
