| 释义 |
‖ roche moutonnée Physical Geogr.|rɔʃ mutɔne|
[Fr., f. roche rock, roche n.1 + moutonnée moutonnée.]
A bare rock outcrop which has been shaped by glacial erosion, characteristically smoothed and rounded by abrasion but often also displaying one side (the ‘downstream’ side) which is rougher and steeper because of plucking. Hence ˌroche mouˈtonnéed a., abounding in roches moutonnées.
De Saussure (see quot. 1786), to whom the term is frequently attributed, applied the adj. moutonnée to small rounded hillocks (usu. covered with vegetation) which suggested, en masse, a fleece or a wig of a style termed moutonnée. These features do not correspond to the meaning of roches moutonnées which later became accepted, and were not associated by de Saussure with glaciers. (See also s.v. in Gloss. Geol. (Amer. Geol. Inst., 1972) 613.)
[1786H.-B. de Saussure Voyages dans Alpes II. xlviii. 512–3 Plus loin, derriere le village de Juviana ou Envionne on voit des rochers qui ont une forme que je nomme moutonnée... Les montagnes que je désigne par cette expression sont composées d'un assemblage de têtes arrondies, couvertes quelquefois de bois, mais plus souvent d'herbes, ou tout au plus de broussailles. Ces rondeurs contigues & répétées forment en grand l'effet d'une toison bien fournie, ou de ces perruques que l'on nomme aussi moutonnées.] 1843J. D. Forbes Trav. through Alps iii. 53 The surface of rock..is even and rounded, often dome-shaped or spheroidal, showing the structure of the rock in section... Such surfaces were called Roches Moutonnées by De Saussure. 1862Q. Jrnl. Geol. Soc. XVIII. 187 For many miles in the Alb Valley, both above and below St. Blasien, roches moutonnées stand like islands through the alluvium. 1865tr. Figuier's World Before Deluge (1891) 443. 1872 C. King Sierra Nevada 70 Here, sheltered among roches moutonnées, began to appear little fields of alpine grass. 1874J. Geikie Gt. Ice Age vii. 90 note, Rocks which are so rounded, whether striated or not, are known as roches moutonnées. 1905Bull. Geol. Soc. Amer. XVI. 51 The northern slopes..have been considerably smoothed by ice action... The whole surface is rochemoutonnéed, especially on the north, where nearly all rocks are absolutely fresh. 1935Discovery Mar. 79/2 Dome-like rocks are exposed which in appearance recall the ice-formed roches moutonnées. 1957J. K. Charlesworth Quaternary Era I. xi. 251 De Saussure gave the name roche moutonnée to the distinctive, rounded forms which abound in glaciated terrain (he himself failed to associate them with ice) and give the effect of a thick fleece or the wavy wigs styled moutonnées in his day (they were slicked down with mutton tallow). 1977A. Hallam Planet Earth 86/3 Many valleys are very deeply incised, with U-shaped cross-profiles and floors composed of smoothed, striated and streamlined rock hummocks (called roches moutonnées). |