670 SEDIMENTARY PROCESSES/Glaciers Figure 10 Microscale erosional landforms: (A) striated and ice moulded limestone at the margin of Glacier de Tsanfleuron, Swiss Alps; (B) crescentic gouges in dolerite beneath Neogene glacigenic sediments, Roberts Massif, Antarctica (ice flow was from left to right); and (C) p forms (melt water eroded and glacially striated channels) cut in limestone, Glacier de Tsanfleuron, Swiss Alps ß 2005, Photographs, M J Hambrey are commonly known as roches moutonne´ es (Figure 11A) Rock grooves are similar in morphology to striae, but have greater size and depth (Figure 11B) They range from tens of metres to hundreds of metres in length and may be up to several metres wide and a few metres deep Rock basins are individual depressions carved in the bedrock, often developed along lines of structural weakness Melt-water channels span a large spatial scale from centimetre- or metre-scale channels cut in soft sediment or bedrock to large valley-scale melt-water channel systems Landforms associated with glacial melt water form wherever sufficient quantities of water are released in subglacial, ice-marginal, and proglacial settings Macroscale landforms of glacial erosion are those features that are at least km in size They are significant landscape components, which may contain within them many of the smaller landforms described above Zones of areal scouring are scoured bedrock consisting of an assemblage of streamlined bedrock features, rock basins, and stoss-and-lee forms Glacial troughs are deep linear features carved into the bedrock, which represent the effects of glacial erosion where ice flow has been confined by topography and channelled along a valley or fjord (Figures 12A and 12B) Cirques are large bedrock hollows that open down-slope and are bounded up-slope by a cliff or steep slope known as a headwall (Figure 12C) Headwall erosion that continues from two opposing sides until they meet produces a sharp ridge – an areˆ te (Figure 12D) If the process takes place from three or more sides, a sharp isolated peak – a horn – may be the product (Figure 12E) Large stoss-and-lee forms (giant roches moutonne´ es) are between hundreds of metres and several kilometres in size These valley spurs and hills have a pronounced asymmetric profile, with an abraded slope on the up-glacier (stoss) side and a steeper rougher quarried slope on the down-glacier (lee) side Bathymetric Forms Resulting from Glacial Erosion Various erosional phenomena, mainly associated with grounded ice or subglacial melt water, are found in marine settings The larger-scale forms are filled by sediment and may be recognizable only in