| 释义 |
protalus Physical Geogr.|prəʊˈteɪləs|
Also pro-talus.
[f. pro-2 + talus1.]
A rocky ridge or lobe on the lower edge of an existing or former snow-bank, composed of frost-fractured boulders and other debris that have slid or rolled over the snow from a talus or scree higher up the slope, or been transported by solifluction from the talus. Usu. attrib., as protalus lobe, protalus rampart.
1934K. Bryan in Geogr. Rev. XXIV. 656 The word ‘nivation’ is the name of a process of excavation around snowbanks described by Matthes. The use of the same word for these ramparts of blocks is likely to prove misleading, and the reviewer suggests that ‘protalus rampart’ would be appropriate for the features. 1962Prof. Papers U.S. Geol. Survey No. 324. 61/2 Many deposits thin downslope to a featheredge, but in the mountains some terminate in a lobate mass bearing one or more arcuate ridges in which the fragments tend to be oriented imbricate to the slope... Such protalus lobes appear to have flowed slowly forward as a unit, presumably by solifluction. 1970R. J. Small Study of Landforms xi. 378 The disintegrated material may slide across the bank of firn below, and accumulate to give moraine-like piles of debris (‘pro-talus’) running approximately parallel to the headwall. 1976Scottish Geogr. Mag. XCII. 182 An excellent example of a protalus rampart occurs in Wester Ross 10 km south-east of Gairloch. Ibid. 184 The protalus complex lies at the foot of a scree slope that rises through a vertical height interval of 100–200 m. |