Younger Dryas glacial moraines

By Dr Richard Waller, Keele University, and Dr Bethan Davies, Royal Holloway University of London

During the Younger Dryas, the Lake District was covered by plateau icefields and cirque glaciers[1]. The image below shows the larger plateau icefields (green) and the smaller cirque glaciers (red) in the Lake District and Snowdonia.

Ice masses in Wales and the Lake District. From Bickerdike et al., 2018

Greenup Gill

These ice masses left behind numerous moraines as they retreated. The image below (credit Dr Richard Waller) shows some 360º imagery of a fabulous set of hummocky moraines in Greenup Gill, near Borrowdale, in the Central Lake District[3]. These glacial landforms show the retreat of a small plateau icefield outlet glacier during the Loch Lomond Stadial[1,3].

The moraines show the retreat of the glacier all the way up onto the plateau, showing the active retreat of this plateau icefield. The continuous moraine sequences shows that the outlet glacier retreated towards its plateau source area without becoming disconnected from the plateau icefield accumulation area[2].

You can see the mapped moraines of this icefield for yourself in the Younger Dryas Glacial Map.

Greenup Gill moraines (dark grey) and the plateau icefield (light gray) from the plateau icefield, Younger Dryas Glacial Map.

Bannerdale

This 360º image shows a lateral moraine (a moraine formed at the sides of the glacier) in Bannerdale (credit Dr Richard Waller). Bannerdale held a small cirque glacier during the Younger Dryas, with lateral moraines demarcating the glacier limits.

In the image below, the lateral moraine is visible as a linear mound of sediment against the valley side walls, in the immediate foreground. Some glacially transported boulders are visible on the ridge of the moraine.

Bannerdale, just to the east of Blencathra, held small cirque glaciers during the Younger Dryas. The orange in this map is mapped as ‘hummocky moraine’ by Sissons (1980).

Haweswater

Haweswater also held a plateau icefield during the Younger Dryas [1,3].

Younger Dryas Glacier Map, showing plateau icefield above Haweswater.

This is a set of moraines above Haweswater (credit Dr Richard Waller). The moraines track the recession of the plateau icefield outlet glaciers onto the upland areas [5].

You can explore these moraines yourself in Google Earth or in the Younger Dryas Glacial Map. The moraines are visible in the satellite imagery as rounded hummocks with scattered boulders.

The Younger Dryas Glacial Map shows the locations of these moraines, just at the head of Haweswater Reservoir.

Younger Dryas moraines at the head of Haweswater Reservoir

Gillercomb

Gillercomb, the valley just to the west of Seathwaite (Cumbria), preserves a number of glacier moraines deposited during the Younger Dryas.

Gillercomb, west of Seathwiate

The location can be explored in Google Maps. The moraines are visible as the smoothed, elongated mounds in the valley floor.

These moraines were formed during the recession of the plateau icefield that covered this part of Cumbria during the Younger Dryas [6].

Gillercomb, west of Seathwaite in Cumbria. Younger Dryas Glacial Map.

Grains Gill

A number of small elongate moraines exist in the bottom of the Derwent river valley, just south of Seathwaite. These moraines have a number of glacially transported boulders on their summits.

Screenshot from the Younger Dryas Glacial Map of Grains Gill moraines.

Here is the location of the mapped geomorphology:

Further reading

References

1. Bickerdike, H. L., Ó Cofaigh, C., Evans, D. J. A. & Stokes, C. R. Boreas 47, 202–224 (2018).

2. Boston, C. M. & Lukas, S. J. Quat. Sci. 34, 433–451 (2019).

3. McDougall, D. A. J. Quat. Sci. Publ. Quat. Res. Assoc. 16, 531–543 (2001).

4. Sissons, J. B. Earth Environ. Sci. Trans. R. Soc. Edinburgh 71, 13–27 (1980).

5. McDougall, D. Quat. Sci. Rev. 73, 48–58 (2013).

6. McDougall, D. A. (1998). Loch Lomond stadial plateau icefields in the Lake District, northwest England. PhD thesis, University of Glasgow.

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