environmental sciences research institute - University of Ulster
environmental sciences research institute - University of Ulster
environmental sciences research institute - University of Ulster
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Geomorphological characteristics and significance <strong>of</strong> Late Quaternary paraglacial rock-slope<br />
failures on Skiddaw Group terrain, Lake District, northwest England<br />
Figure 2. Rock slope failure on Crag Fell, Lake District<br />
Eight relict rock-slope failures have been investigated on Skiddaw Group terrain in the Lake District, northwest England.<br />
Five <strong>of</strong> the failures are rockslides, one is a product <strong>of</strong> slope deformation, and two are compound features with evidence<br />
for sliding and deformation in different sectors. Because none <strong>of</strong> the failures appear to have been overrun and modified<br />
by glacier ice it is inferred that they all post-date the Last Glacial Maximum (c. 21,000 years Before Present). Slope stress<br />
readjustments resulting from glacial and deglacial influences are considered to have weakened the slopes, and application<br />
<strong>of</strong> the term paraglacial is appropriate. Permafrost aggradation and degradation, seismic activity and fluvial erosion are<br />
among processes that may have contributed to failure at certain sites. The failures are significant as potential debris<br />
sources during future ice advances, contributing to valley widening and cirque enlargement and, possibly, for acting as<br />
sites <strong>of</strong> cirque initiation. Previously, Skiddaw Group rocks have been regarded as homogeneous and <strong>of</strong> limited resistance<br />
to the weathering and erosion associated with Quaternary glacial, periglacial and fluvial processes. These characteristics<br />
and processes have been used to explain the steep smooth slopes and rounded hills that dominate Skiddaw Group<br />
terrain. Rock-slope failure has also helped shape this terrain and should be incorporated in future interpretations <strong>of</strong><br />
landscape development.<br />
Peter Wilson<br />
<br />
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