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ABSTRACT Towards the end of the last glaciation, ice sourced from the western Grampian Mountains of Scotland flowed down Strath Spey to encroach on the northern flanks of the Cairngorm Mountains. The maximum of this late advance and its subsequent retreat is recorded by moraines, ice-marginal meltwater channels, and kame terraces that can be traced for 60 km along Strath Spey. New cosmogenic 10Be exposure ages from moraines indicate deglaciation at 15.1 ± 1.1 ka. This timing matches closely the recalibrated mean ages of 14.7 ± 0.7 and 15.2 ± 0.7 ka for the Wester Ross Readvance in the North-West Highlands. A synchronous readvance of the British-Irish Ice Sheet (BIIS) towards the end of Greenland Stadial 2a (GS-2a) (16.9-14.7 ka) is indicated. Thereafter active ice retreat from the flanks of Strath Spey was rapid, occurring within the ∼1 ka uncertainty of the cosmogenic exposure ages. We suggest the advance followed the collapse of the marine parts of the BIIS at ∼16 ka due to conditions of increased precipitation occurring at a time of low temperatures. The rapidity of deglaciation may reflect enhanced Föhn effects caused by the ice dome in the western Grampians. [ABSTRACT FROM AUTHOR]

Abstract: The buzzsaw hypothesis refers to the potential for glacial and periglacial processes to rapidly denude mountains at and above glacier Equilibrium Line Altitudes (ELAs), irrespective of uplift rates, rock type or pre-existing topography. Here the appropriateness of the buzzsaw metaphor is examined alongside questions of the links between glacial erosion and ELAs, and whether the glacial system can produce low-relief surfaces or limit summit heights. Plateau fragments in mountains on both active orogens and passive margins that have been cited as products of glacial and periglacial buzzsaw erosion instead generally represent dissected remnants of largely inherited, pre-glacial relief. Summit heights may correlate with ELAs but no causal link need be implied as summit erosion rates are low, cirque headwalls may not directly abut summits and, on passive margins, cirques are cut into pre-existing mountain topography. Any simple links between ELAs and glacial erosion break down on passive margins due to topographic forcing of ice-sheet growth, and to the km-scale vertical swaths through which ELAs have shifted through the Quaternary. Glaciers destroy rather than create low-relief rock surfaces through the innate tendency for ice flow to be faster, thicker and warmer along valleys. The glacial buzzsaw cuts down. [Copyright &y& Elsevier]

We seek to quantify glacial erosion in a low relief shield landscape in northern Sweden. We use GIS analyses of digital elevation models and field mapping of glacial erosion indicators to explore the geomorphology of three granite areas with the same sets of landforms and of similar relative relief, but with different degrees of glacial streamlining. Area 1, the Parkajoki district, shows no streamlining and so is a type area for negligible glacial erosion. Parkajoki retains many delicate pre-glacial features, including tors and saprolites with exposure histories of over 1 Myr. Area 2 shows the onset of significant glacial erosion, with the development of glacially streamlined bedrock hills. Area 3 shows extensive glacial streamlining and the development of hill forms such as large crag and tails and roches moutonnées. Preservation of old landforms is almost complete in Area 1, due to repeated covers of cold-based, non-erosive ice. In Area 2, streamlined hills appear but sheet joint patterns indicate that the lateral erosion of granite domes needed to form flanking cliffs and to give a streamlined appearance is only of the order of a few tens of metres. The inheritance of large-scale, pre-glacial landforms, notably structurally controlled bedrock hills and low relief palaeosurfaces, remains evident even in Area 3, the zone of maximum glacial erosion. Glacial erosion here has been concentrated in valleys, leading to the dissection and loss of area of palaeosurfaces. Semi-quantitative estimates of glacial erosion on inselbergs and palaeosurfaces and in valleys provide mean totals for glacial erosion of 8 ± 8 m in Area 1 and 27 ± 11 m in Area 3. These estimates support previous views that glacial erosion depths and rates on shields can be low and that pre-glacial landforms can survive long periods of glaciation, including episodes of wet-based flow. [ABSTRACT FROM AUTHOR]

The article discusses research being done on climate on mountain ranges in Earth. It references the study "Glacial Cirques and the Relationship Between Equilibrium Line Altitudes and Mountain Range Height" by S. G. Mitchell and E. E. Humphries in the 2015 issue. Topics discussed include the cause of limited peaks within the quarternary average glacier equilibrium line altitude (QA-ELA), the reason for the presence of cirque glaciers in valley heads, and a description of glacial ridges.