The Brampton kame belt and Pennine escarpment meltwater channel system (Cumbria, UK): Morphology, sedimentology and formation

Abstract

The Brampton kame belt represents one the largest glaciofluvial complexes within the UK. It is composed of an array of landform and sediment assemblages, associated with a suite of meltwater channels and situated within a palimpsest landscape of glacial features in the heart of the most dynamic part of the British-Irish ice sheet. Glacial geomorphological mapping and sedimentological analysis has allowed a detailed reconstruction of both the morphological features and the temporal evolution of the Brampton kame belt, with processes informed by modern analogues from modern ice margins. The kame belt demonstrates the development of a complex glacier karst typified by the evolution of subglacial meltwater tunnels into an englacial and supraglacial meltwater system dominated by ice-walled lakes and migrating ice-contact drainage networks. Topographic inversion led to the extensive reworking of sediments, with vertical collapse (associated with the melt-out of dead ice) and debris flows causing partial disintegration of the morphology. The resultant landform comprises a series of kettle holes, discontinuous ridges (eskers) and flat-topped hills (ice-walled lake plains). The Pennine escarpment meltwater network, which fed the Brampton kame belt, is composed of an anastomosing subglacial channel system and flights of lateral channels. Water was transferred into the subglacial system via a series of subglacial chutes during changes in the basal ice thermal regime. The Brampton kame belt is envisaged to have formed during the stagnation of ice in the lee of the Pennines and Penrith sandstone outcrop as ice retreated westwards across the Tyne Gap into the Solway Lowlands. The formation of the Brampton kame belt also has particular conceptual resonance in terms of constraining the nature of kame genesis, whereby an evolving glacier karst is a key mechanism in the spatial and temporal development of ice contact sedimentlandform associations.

Scottish Landform Examples 43: Glacifluvial Landforms of Strathallan, Perthshire

“…A gradual change in the nature of glacial meltwater channel incision appears to be documented in the pattern of channel types, as classified in Figure 9. A similar spatial and temporal evolution of drainage styles based upon meltwater channel types has been documented in other parts of the British Isles (Greenwood et al 2007;Livingstone et al 2010aLivingstone et al , 2010b and is characterized by inset sequences of marginal, sub-marginal and subglacial channels which reflect the changing nature of the glacial hydrology and glacier thermal regime. This features the development of cold-based margins at the more advanced (topographically confined) stages of ice sheet recession, as marked by lateral/marginal meltwater channels (light blue on Figure 9), which then grade downslope/temporally into sub-marginal (green) and then subglacial (dark blue) channels as the thermal regime warms.…”

“…The former pathways of glacial meltwater are often easy to reconstruct in a deglaciated landscape because they are delineated by either channels eroded by the water (Mannerfelt 1949;Sissons 1960Sissons , 1961Dyke 1993) or the variously shaped concentrations of debris that filled the ice-walled tunnels, caverns, cavities and ponds, collectively known as 'eskers', 'kame and kettle topography' and 'ice-walled lake plains' or 'kame plateaux' (Rich 1943;Cook 1946;Price 1969;Warren & Ashley 1994;Thomas & Montague 1997;Clayton et al 2008;Livingstone et al 2010aLivingstone et al , 2010bStorrar et al 2015; Figure 2), all of which occur in juxtaposition in areas where glacial meltwater activity was concentrated and melting out englacial debris was in abundant supply. In addition, 'kame terraces' markthe former positions of ice-marginal river beds and hence tend to appear terrace-like immediately after their initial formation but, because they contain a large amount of glacier ice, will undergo widespread collapse due to melt out (McKenzie 1969).…”

“…The early phase of enhanced lateral meltwater incision around the Strathallan lobe must have been in response to restricted drainage access to the glacier bed and hence a predominantly cold-based thermal regime, at least around the upper margins of the lobe. Although the occurrence of eskers on the valley floor might appear to contradict this interpretation, tunnel infills (eskers) are not exclusively subglacial in origin and indeed many modern eskers, forming even in temperate glaciers, are emerging at present from englacial positions (Price 1969;Livingstone et al 2010aLivingstone et al , 2010bStorrar et al 2015). Hence the Strathallan valley floor eskers, at least in part, could have been let down onto the substrate from englacial tunnels.…”

Fláajökull (north lobe), Iceland: active temperate piedmont lobe glacial landsystem

“…The evolution of the area from a largely flat but locally pitted outwash surface to a large depression containing gravel and sand mounds and esker ridges displays all the process-form relationships of areas of melting glacier snouts buried by glacifluvial outwash and containing englacial drainage tunnels. Similar landform assemblages have evolved at the margins of Breiðamerkurjökull (Evans & Twigg, 2002), Kvíárjökull (Bennett & Evans, 2012;Bennett et al, 2010) and Virkisjökull/Falljökull (Bradwell, Sigurðs-son, & Everest, 2013;Livingstone, Evans, Cofaigh, & Hopkins, 2010), where meltwater drainage appears to have bypassed over-deepenings in the subglacial environment.…”

Vývoj Ledovcových Sedimentů Na Kontaktu S Žulovským Masivem Ve Štachlovicích U Vidnavy

“…Supraglaciální glacifl uviální sedimenty bývají zahloubeny do ledovce. Po jeho roztátí se výplně koryt stanou konvexními tvary reliéfu, jejich okraje zkolabují a sedimentární záznam se zdeformuje (Livingstone et al 2010). To je v porovnání s členy 4 a 5 zcela opačná situace.…”