| 释义 |
ˈoutwash Geol.
[out- 7.]
Material (chiefly sand and gravel, or further away silt and clay) carried out from a glacier by melt-water and deposited beyond the terminal moraine. Freq. attrib.
1894T. C. Chamberlin in Jrnl. Geol. II. 533 There were, however, tracts of assorted material formed by waters outflowing from the ice where no definite terminal ridging took place. Such forms may be designated outwash aprons in distinction from overwash aprons. 1905Ibid. XIII. 245 One of the pronounced features of the outwash is the pitted-plain development. 1908Amer. Jrnl. Sci. CLXXV. 108 The river terraces of outwash gravel. 1934Antiquity VIII. 306 The retreat of the ice and the formation of the outwash plain in front of the moraine. 1947Auden Age of Anxiety v. 116 And you, bright Prince,..O stiffly stand, a staid monadnock, On her peneplain; placidly graze On her outwash apron, her own steed. 1957[see overwash n.]. 1963D. W. & E. E. Humphries tr. Termier's Erosion & Sedimentation vii. 163 During the recession of the Quaternary ice sheets, detrital accumulations were left behind, either in the form of outwash fans deposited at the snouts of glaciers by subglacial streams.., or as fluvio-glacial ridges often filling in lakes (eskers). 1971R. F. Flint Glacial & Quaternary Geol. vii. 187 In the downstream direction, outwash is diluted by an ever-increasing proportion of nonglacial alluvium derived through tributary streams that did not originate in glaciers. 1972J. G. Cruickshank Soil Geogr. ii. 59 Outwash alluvium is usually similar in texture, but may include some fine debris where the melt water has spread over a large area. |