Surging glaciers in Scotland

Abstract

Glacier surges are cyclic oscillations of velocity and mass resulting from internal dynamic instabilities. For surge-type glaciers, cycles of advance and retreat are decoupled from climate forcing, so it is important to consider the possibility that former glaciers may have been surge-type when making climatic inferences from their dimensions and chronologies. In this paper, climatic and glacier geometric data are used to show that Scotland was likely the location of a surge cluster during the Loch Lomond Stade (∼12.9-11.7 ka), with high probabilities of surging for outlets of the West Highland Icefield and the larger glaciers in the Inner Hebrides and Northern Highlands. Terrestrial and marine landforms consistent with surging occur in all of these areas, and it is proposed that surge-type glaciers existed on the Islands of Skye and Mull, in the Northern Highlands, and in a 'surging arc' along the western, southern and south-eastern margins of the West Highland Icefield. The possibility that surge-type glaciers were widespread in Scotland during the Loch Lomond Stade offers a fresh perspective on some long-standing issues, including the relationship between style of deglaciation and climate change, the climatic significance of glacial chronologies, palaeoclimatic reconstructions, and the interpretation of numerical model results.

Lateglacial Shifts in Seasonality Reconcile Conflicting North Atlantic Temperature Signals

“…Finally, a 14 C‐dated stratigraphic section at Croftamie, near the terminus of the former Loch Lomond glacier, is widely cited as robust evidence for the LLR culminating late in the YD (Benn, 2021; Lowe et al., 2019; Macleod et al., 2011). This interpretation assumes that the overlying “Gartocharn till” was deposited as lodgement till by the advancing glacier (Coope & Rose, 2008; Rose, 1981; Rose et al., 1988), in which case the ten 14 C dates on underlying plant remains afford a maximum‐limiting age for the advance (Macleod et al., 2011; Rose et al., 1988).…”

Formation of crevasse‐squeeze ridges at Trygghamna, Svalbard

“…Ankerstjerne et al, 2015; Aradóttir et al, n.d. ; Benn, 2021; Darvill et al, 2017; Delaney et al, 2018; Evans et al, 2016; Lamsters et al, 2021; Sutherland et al, 2019, in review). CSR networks occur in submarginal to subglacial landform assemblages of the terrestrial surging‐glacier landsystem, with flutes, hummocks, pitted outwash and zig‐zag eskers (Evans et al, 2007, 2016; Evans & Rea, 1999, 2003; Schomacker et al, 2014).…”

Surge-type Uisu glacier and its undisturbed forefield relief, Eastern Pamir, Tajikistan

“…Based on the geomorphological evidence, it can only be concluded that, when surging, the Uisu glacier did not form any glacial landforms in its present-day forefield. It can also be expected that in the future, after the ice has completely melted in the terminal area with the supraglacial cover, the current extent of the Uisu glacier will be revealed by the spread of the hummocky moraine and by other glacial landforms formed in this zone (Benn 2021), if the latter are not buried or washed out during deglaciation. Therefore, the presence of hummocky moraine in the glaciated areas in the past and, at the same time, the lack of marginal glacial landforms, may indicate not only the long-term stagnation of the glacial terminal zone, but also a past surge.…”

“…Serrano & Martín-Moreno 2018). The maximum extents of some Pleistocene glacier lobes and glaciers in the mountains of North America and Europe could also have been associated with surging (Evans & Rea 1999;Benn 2021).…”