| 释义 |
aggrade, v. Geol.|əˈgreɪd|
[f. ag- + grade, after degrade.]
trans. To fill up (a river bed, valley, etc.) with detritus. Also intr., to build up by aggradation. (The opposite of degrade v. 6.) Hence aˈggraded, aˈggrading ppl. adjs.; also aggraˈdation, the process of raising a surface by the deposition of detritus; whence aggraˈdational a.
1898T. C. Chamberlin in Jrnl. Geol. VI. 524 The degradation of the one furnishes the material for the aggradation of the other. 1902Ibid. X. 758 The alternate depositional and aggradational work..done by the Missouri river. Ibid. 759 The channel at present is in a slightly aggraded and apparently still aggrading stage. Ibid. 760 The aggradation stage has..been inaugurated by the detour of the river... The present aggrading washes have made a little bottom in the lower twenty rods of the valley. 1904Chamberlin & Salisbury Geol. (1905) I. i. 2 The deposition of material, whether on the land or in the sea, is aggradation. Ibid. 178 Streams carrying glacial drainage are usually aggrading streams. Ibid. 184 The stream in flood aggrades its plain, and degrades its channel. 1937Wooldridge & Morgan Physical Basis Geogr. xii. 173 Flood alluviation, like aggradation by gravel, is closely linked with the development of meanders. 1946F. E. Zeuner Dating the Past v. 130 In its course near the sea..a river aggrades during the mild phases and erodes during the cool phases. |