Glacial landsystems, retreat dynamics and controls on Loch Lomond Stadial (Younger Dryas) glaciation in Britain

Abstract

Glacial geomorphology relating to the Loch Lomond Stadial (Younger Dryas) in Britain is used to construct five glacial landsystem models. These landsystems lie on a continuum of increasing ice thickness and decreasing topographic control and typify the principal styles of glaciation during the stadial. The landsystems comprise: the cirque/niche glacier landsystem, the alpine icefield landsystem, the lowland piedmont lobe landsystem, the plateau icefield landsystem and the icecap landsystem. Geomorphological features representing the icecap landsystem are present only at the centre of the West Highland Glacier Complex, which was flanked primarily by satellite alpine and plateau icefields. The cirque/niche glacier landsystem was present predominantly in areas that experienced conditions only marginally favourable for glacier development at peripheral sites. Three styles of glacier retreat are recorded by the geomorphology: active, two-phase and uninterrupted retreat. Of these, active retreat appears to be most widespread within the Loch Lomond Stadial limits. These retreat styles reflect a combination of climatic and topographic conditions, coupled with local factors influencing the preservation of landforms from which retreat dynamics can be inferred. Likewise, the distribution of landsystems was influenced by an interplay between topography and climate, with glacier formation being facilitated in locations where topographical conditions aided in the accumulation of snow. The pattern also supports the existence of previously recognized northward and eastward precipitation gradients across Britain during the stadial.

Topographic controls on plateau icefield recession: insights from the Younger Dryas Monadhliath Icefield, Scotland

“…Whilst this study can by no means attempt to address these issues, we discuss the style of recession in relation to previous work and with respect to possible timings of maximum extent. Differences in recession patterns between areas in Britain have been discussed recently by Bickerdike et al (2018b), who identified three styles of retreat: 'active retreat' (spatially organized moraines throughout recession), 'two-stage retreat' (spatially organized moraines initially with chaotic moraines indicative of stagnation closer to the source area) and 'uninterrupted retreat' (no geomorphological evidence inside the outermost moraines). These authors suggest that the dominance of active retreat across Scotland may support the view that recession began in the mid-stadial, with glaciers responding to a gradual increase in temperatures rather than a more rapid and pronounced increase at the end of the stadial (cf.…”

“…3), and the potential that as ice thinned it became cold-based and ceased forming moraines for this reason. The aforementioned pattern of recession may therefore not be Copyright (2019) entirely climatically controlled (sensu Benn et al, 1992;Bickerdike et al, 2018b) and could instead relate to a strong topographic influence on recession in a plateau icefield setting and the potential for 'tipping points' between active and uninterrupted recession. The ability of outlet glaciers to continue producing moraines, almost continuously in many cases, into the final stages of icefield demise indeed suggests that a rapid warming did not cause the uninterrupted recession and stagnation observed elsewhere on the plateau.…”

The glacial geomorphology of the Loch Lomond (Younger Dryas) Stadial in Britain: a review

“…Cumulatively, the shift towards icefield styles of glaciation and mapping of new areas indicates that a much larger area of Britain was glaciated during the LLS than previously thought. These limits accord with those derived from numerical modelling (Golledge et al ., ), supporting the long‐held assumption that glaciation in the central and eastern Grampians was restricted by the reduced precipitation levels in these regions (Sissons and Sutherland, ; Golledge, ; Bickerdike et al, ).…”

The glacial landsystem of a tropical glacier: Charquini Sur, Bolivian Andes

“…the nature of ice-marginal and subglacial environments, glacier thermal regimes, sediment transport pathways in the glacier system). Stokes and Clark, 1999;Golledge, 2007;Darvill et al, 2017;Bickerdike et al, 2018). surging), known as glacial landsystems (cf.…”

“…Evans, 2003ab;Glasser and Hambrey, 2003;Kjaer et al, 2008;Graham et al, 2009;Brynjólfsson et al, 2014;Schomacker et al, 2014;Ewertowski et al, 2016) and in the palaeoglacial record (e.g. Stokes and Clark, 1999;Golledge, 2007;Darvill et al, 2017;Bickerdike et al, 2018). This ongoing work has revealed that, due to the influence of different climatic, topographic and geological settings, no universal landform pattern exists for glacial environments, and different glacier subtypes often exhibit their own typical geomorphological and sedimentological footprint (Evans, 2003a;Benn et al, 2003;Hambrey and Glasser, 2012;Ingólfsson et al, 2016).…”