A palaeoclimatic reconstruction of the Cadair Idris area of Snowdonia, using geomorphological evidence from Younger Dryas cirque glaciers

Bethany Radbourne


The importance of glacier reconstruction lies in the empirical relationship between glacier mass balance and climate. Small glaciers are particularly sensitive to changes in temperature and precipitation, thus the reconstruction of small palaeoglaciers can provide an understanding of past climatic changes in an area. This study conducts glacier and palaeoclimatic reconstructions for four potential palaeoglaciers at Cadair Idris, southern Snowdonia. Three of these are assigned a Younger Dryas age by referring to published literature, and the fourth is assumed to have existed during an earlier glaciation, possibly reflecting deglaciation from the Last Glacial Maximum (LGM). Schmidt Hammer relative age dating is carried out to establish relative ages between landforms within the cirque areas, however the results from this are inconclusive as the process is subject to many errors. The topographically-constrained Younger Dryas cirque glaciers, referred to as Cwm Cau, Cwm Gadair and the small eastern glacier, occupied a total area of 0.963km2.  Calculations of Equilibrium Line Altitudes (ELAs) yield an average local ELA of 607m asl. Subsequent palaeoclimatic reconstructions indicate that during the Younger Dryas, annual precipitation levels were similar to, or higher than, present levels, averaging at 2850mm a-1. Consideration is given to the potential for additional mass to be added to the glaciers through snowblow, but it is concluded that the relatively small snowblow factors, ranging from 0.71 to 1.32, would not have contributed much mass to the glaciers. Total avalanche factors range from 0.27 to 0.92 and are suggested to be more likely to contribute mass to the glaciers. Solar radiation maps for the ablation season indicate that the high cirque walls would have provided shading from the most intense incoming solar radiation, thus protecting certain parts of the glaciers and encouraging initial ice accumulation and preservation, possibly explaining the existence of a western lobe of the Cwm Gadair glacier. Finally, calculations of the glaciological dynamics of the glaciers indicate that the small eastern glacier was not, in fact, viable as a glacier under the reconstructed palaeoclimatic conditions.

Full Text:



Ahlmann, H. W., 1948. Glaciological research on the North Atlantic coasts. Royal Geographical Society Research Series, Volume 1, pp. 84.

Andrews, J. T., 1972. Glacier power, mass-balance, velocities and potential erosion. Zeitschrift für Geomorphologie Supplementbände, Volume 13, pp. 1-17.

Arnold, N. S., Rees, W. G., Hodson, A. J. & Kohler, J., 2006. Topographic controls on the surface energy balance of a high Arctic valley glacier. Journal of Geophysical Research, Volume 111, F02011.

Ballantyne, C. K., 2001. Cadair Idris: A Late Devensian Palaeonunatak. In: M. J. Walker & D. McCarroll, eds. The Quaternary of West Wales. London: Quaternary Research Association, pp. 126-131.

Ballantyne, C. K., 2002. The Loch Lomond Readvance on the Isle of Mull, Scotland: glacier reconstruction and palaeoclimatic implications. Journal of Quaternary Science, 17(8), pp. 759-771.

Ballantyne, C. K., 2007. Loch Lomond Stadial glaciers in North Harris, Outer Hebrides, North-west Scotland: glacier reconstruction and palaeoclimatic implications. Quaternary Science Reviews, Volume 26, pp. 3134-3149.

Basagic, H. J. & Fountain, A. J., 2011. Quantifying 20th Century Glacier Change in the Sierra Nevada, California. Arctic, Antarctic and Alpine Research, 43(3), pp. 317-330.

Bendle, J. M. & Glasser, N. F., 2012. Palaeoclimatic reconstruction from Lateglacial (Younger Dryas Chronozone) cirque glaciers in Snowdonia. Proceeding of the Geologists' Association, Volume 123, pp. 130-145.

Benn, D. I. & Hulton, N., 2010. An Excel(TM) spreadsheet program for reconstructing the surface profile of former mountain glaciers and ice caps. Computers & Geosciences, Volume 36, pp. 605-610.

Benn, D. I. & Ballantyne, C. K., 2005. Palaeoclimatic reconstruction from Loch Lomond Readvance glaciers in the West Drumochter Hills, Scotland. Journal of Quaternary Science, 20(6), pp. 557-592.

Benn, D. I. & Evans, D. J., 2010. Glaciers & Glaciation. 2nd ed. Oxon: Routledge.

Benn, D. I. & Lehmkuhl, F., 2000. Mass balance and equilibrium-line altitudes of glaciers in high-mountain environments. Quaternary International, Volume 65/66, pp. 15-29.

Benn, D. I., Owen, L. A., Osmaston, H. A., Seltzer, G. O., Porter, S. C., Mark, B., 2005. Reconstruction of equilibrium-line altitudes for tropical and sub-tropical glaciers. Quaternary International, 8(21), pp. 138-139.

Berger, A. & Loutre, M., 1991. Insolation values for the climate of the last 10 million years. Quaternary Science Reviews, Volume 10, pp. 297-317.

Carr, S. J., 2001. A glaciological approach for the discrimination of Loch Lomond Stadial glacial landforms in the Brecon Beacons, South Wales. Proceedings of the Geologists' Association, Volume 112, pp. 253-261.

Carr, S. J. & Coleman, C. G., 2007. An improved technique for the reconstruction of former glacier mass-balance and dynamics. Geomorphology, Volume 92, pp. 76-90.

Carr, S. J., Lukas, S. & Mills, S. C., 2010. Glacier reconstruction and mass-balance modelling as a geomorphic and palaeoclimatic tool. Earth Surface Processes and Landforms, Volume 35, pp. 1103-1115.

Chueca, J. & Julián, A., 2004. Relationship between solar radiation and the development and morphology of small cirque glaciers (Maladeta mountain massif, Central Pyrenees, Spain). Geografiska Annaler, 86A(1), pp. 81-89.

Coleman, C. G. & Carr, S. J., 2008. Complex relationships between Younger Dryas glacial, periglacial and paraglacial landforms, Brecon Beacons, South Wales. Proceedings of the Geologists' Association, Volume 119, pp. 259-276.

Coleman, C. G., Carr, S. J. & Parker, A. G., 2009. Modelling topoclimatic controls on palaeoglaciers: implications for inferring palaeoclimate from geomorphic evidence. Quaternary Science Reviews, Volume 28, pp. 249-259.

Cronin, T. M., 2010. Paleoclimates: Understanding Climate Change Past and Present. New York: Colombia University Press.

Evans, I. S., 2006. Allometric development of glacial cirque form: Geological, relief and regional effects on the cirques of Wales. Geomorphology, Volume 80, pp. 245-266.

Gray, J. M., 1982. The last glaciers (Loch Lomond advance) in Snowdonia, N. Wales. Geological Journal, Volume 17, pp. 111-133.

Glen, J. W., 1952. Experiments on the deformation of ice. Journal of Glaciology, Volume 2, pp. 111-114.

Hopkinson, C., Chasmer, L., Munro, S. & Demuth, M. N., 2010. The influence of DEM resolution on simulated solar radiation-induced glacier melt. Hydrological Processes, Volume 24, pp. 775-788.

Hughes, P. D., 2002. Loch Lomond Stadial glaciers in the Aren and Arenig Mountains, North Wales, Great Britain. Geological Journal, Volume 37, pp. 9-15.

Hughes, P. D., 2009. Loch Lomond Stadial (Younger Dryas) glaciers and climate in Wales. Geological Journal, Volume 44, pp. 375-391.

Ince, J. J., 1983. Two postglacial pollen profiles from the uplands of Snowdonia, Gwynedd, North Wales,. New Phytologist, Volume 95, pp. 159-172.

IPCC Working Group I, 2013. Climate Change 2013: The Physical Scence Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge: Cambridge University Press.

Kern, Z. & László, P., 2010. Size specific steady-state accumulation-area ratio: an improvement for equilibrium-line estimation of small palaeoglaciers. Quaternary Science Reviews, Volume 29, pp. 2781-2787.

Klapyta, P., 2013. Application of Schmidt Hammer relative age dating to Late Pleistocene moraines and rock glaciers in the Western Tatra Mountains, Slovakia. Catena, Volume 111, pp. 104-121.

Larsen, K. A., 1999. The Late Devensian glacial history of Cadair Idris. Unpublished MA thesis, University of St Andrews, 65pp.

López-Moreno, J. I., Noguéz-Bravo, D., Chueca-Cía, J. & Julián-Andrés, A., 2006. Glacier development and topographic context. Earth Surface Processes and Landforms, Volume 31, pp. 1585-1594.

Lowe, J. J. et al., 2008. Synchronisation of palaeoenvironmental events in the North Atlantic region during the Last Termination: a revised protocol recommended by the INTIMATE group. Quaternary Science Reviews, Volume 27, pp. 6-17.

Lowe, S., 1993. The Devensian Lateglacial and Early Flandrian stratigraphy of southern Snowdonia, North Wales, University of London: Unpublished PhD thesis.

Lukas, S. & Bradwell, T., 2010. Reconstruction of a Lateglacial (Younger Dryas) mountain ice field in Sutherland, northwestern Scotland, and its palaeoclimatic implications. Journal of Quaternary Science, Volume 25, pp. 567-580.

Matthews, J. A. & Shakesby, R. A., 1984. The status of the 'Little Ice Age' in southern Norway: relative-age dating of neoglacial moraines with Schmidt hammer and lichenometry. Boreas, Volume 13, pp. 333-346.

McDougall, D., 2013. Glaciaton style and the geomorphological record: evidence for Younger Dryas glaciers in the eastern Lake District, northwest England. Quaternary Science Reviews, Volume 73, pp. 48-58.

Met Office, 2014. Capel Curig climate. [Online]

Available at: http://www.metoffice.gov.uk/public/weather/climate/gcmnn3630

[Accessed 14. 12. 2014].

Met Office, 2014. Gogerddan climate. [Online]

Available at: http://www.metoffice.gov.uk/public/weather/climate/gcm4k8cnp

[Accessed 14. 12. 2014].

Mitchell, W. A., 1996. Significance of snowblow in the generation of Loch Lomond Stadial (Younger Dryas) glaciers in the western Pennines, northern England. Journal of Quaternary Science, 11(3), pp. 233-248.

Ohmura, A., Kasser, P. & Funk, M., 1992. Climate at the equilibrium line of glaciers. Journal of Glaciology, Volume 38, pp. 397-411.

Osipov, E. Y. & Khlystov, O. M., 2010. Glaciers and meltwater flux to Lake Baikal during the Last Glacial Maximum. Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 294, pp. 4-15.

Osmaston, H., 2005. Estimates of glacier equilibrium line altitudes by the Area x Altitude, the Area x Altitude Balance Ratio and the Area x Altitude Balance Index methods and their validation. Quaternary International, Volume 138-139, pp. 22-31.

Paterson, W. S. B., 1994. The Physics of Glaciers. 3rd ed. Oxford: Pergamon.

Plummer, M. A. & Phillips, F. M., 2003. A 2-D numerical model of snow/ice energy balance and ice flow for palaeoclimatic interpretation of glacial geomorphic features. Quaternary Science Reviews, Volume 22, pp. 1389-1406.

Porter, S. C., 1975. Equilibrium line altitudes of late Quaternary glaciers in the Southern Alps, New Zealand. Quaternary Research, Volume 5, pp. 27-47.

Rea, B. R., 2009. Defining modern day Area-Altitude Balance Ratios (AABRs) and their use in glacier-climate reconstructions. Quaternary Science Reviews, Volume 28, pp. 237-248.

Sahlin, E. A. & Glasser, N. F., 2008. A geomorphological map of Cadair Idris. Journal of Maps, pp. 299-314.

Schytt, V., 1967. A study of ‘ablation gradient’. Geografiska Annaler, Volume 49A, pp. 327-332.

Shakesby, R. A. & Matthews, J. A., 1996. Glacial activity and paraglacial landsliding in the Devensian Lateglacial: evidence from Craig Cerrig-gleisiad and Fan Dringarth, Fforest Fawr (Brecon Beacons, South Wales). Geological Journal, Volume 31, pp. 143-157.

Shakesby, R. A., Matthews, J. A. & Owen, G., 2006. The Schmidt Hammer as a relative-age dating tool and its potential for calibrated-age dating in Holocene glaciated environments. Quaternary Science Reviews, Volume 25, pp. 2846-2867.

Sissons, J. B., 1974. A Late-Glacial Ice Cap in the Central Grampians, Scotland. Transactions of the Institute of British Geographers, Volume 62, pp. 95-114.

Sissons, J. B., 1980. The Loch Lomond Advance in the Lake District, northern England. Transactions of the Royal Society of Edinburgh: Earth Sciences, 71(1), pp. 13-27.

Trelea-Newton, M. & Golledge, N. R., 2012. The Younger Dryas glaciation in the southeastern Monadhliath Mountains, Scotland: glacier reconstruction and palaeoclimatic implications. BOREAS: An international journal of Quaternary research, Volume 41, pp. 614-628.

Walker, M. J. C., Coope, G. R., Sheldrick, C., Turney, C. S. M., Lowe, J. J., Blockely, S. P. E., Harkness, D. D., 2003. Devensian Lateglacial environmental changes in Britain: a multi-proxy environmental record from Llanilid, South Wales, UK. Qauternary Science Reviews, Volume 22, pp. 475-520.


  • There are currently no refbacks.

Creative Commons License 
This work is licensed under a Creative Commons Attribution 3.0 License

ISSN 1754-2383 [Online] ©University of Plymouth