| 释义 |
planation Geomorphol.|pləˈneɪʃən|
[f. L. plān-um plane n.3 + -ation.]
The levelling of a landscape by erosion.
1877G. K. Gilbert Rep. Geol. Henry Mts. 127 The process of carving away the rock so as to produce an even surface, and at the same time covering it with an alluvial deposit, is the process of planation. 1892A. J. Jukes-Brown Student's Handbk. Physical Geol. (ed. 2) iii. i. 565 A tract of land which has been submerged and then upraised must have been twice subjected to this levelling process, and on its second emergence would present a wide area with a nearly level or slightly undulating surface. Such an area has been termed a plain of marine erosion, but would perhaps be more aptly called a surface of planation. 1935Geogr. Jrnl. LXXXV. 171 It is only where planation occurred during the subsequent Jurassic submergence that the surface is really level, as on the Mendips. 1963D. W. & E. E. Humphries tr. Termier's Erosion & Sedimentation ii. 35 The most perfect planations imply a succession of complex phenomena, which include transportation and deposition of sediments as well as erosion. 1970R. J. Small Study of Landforms iv. 131 The interfluves of Dartmoor, besides preserving remains of planation surfaces, show in detail features of interest. 1976A. N. Strahler Princ. Earth Sci. xiv. 208/1 The floodplain is widened by further lateral planation.
So plaˈnated ppl. a., made level by erosion; also (as a back-formation) plaˈnate v. trans.
1912Jrnl. Geol. XX. 450 Old planated surfaces..now dissected because of readjustments of drainage due to faulting. 1937Geogr. Jrnl. XC. 56 The planated aspect of Waterpit Down from 900–850 feet suggests that this is a fragment of the erosion surface related to this bluff. 1954W. D. Thornbury Princ. Geomorphol. xi. 286 Paige (1912) concluded that the processes of interstream and lateral erosion at the edges of alluvial fans would produce a sloping planated surface cut on bedrock which would become buried toward the center of a basin under a cover of gravel. 1969Trans. Inst. Brit. Geogr. XLVIII. 44 Till and bedrock were planated to produce a surface sloping gently towards the Forth. |