Mam Tor is 2 km north-west of Castleton in the Peak District where it stands between the White Peak and Dark Peak.
The summit of Mam Tor is ringed by the remains of a great ditch and rampart of a once great Iron Age hillfort but it is also famous for its large landslide (Figure 1). The landslide is easy to access and exhibits classic text-book landslide features so is a good landslide for geologists, geomorphologists, geographers and engineers to study. It is National Landslide Database ID 5481/1.
The Sheffield Turnpike Company first constructed the A625 Manchester to Sheffield road in 1819 using spoil from the nearby Odin mine (National Trust, 2009) and the road crosses the main body of the landslide twice as it winds its way up the slope. The following 160 years saw constant repairs and reconstruction. In 1977, the landslide moved again and the road was restricted to single-lane traffic (Cripps and Hird, 1992). In 1979, the road was permanently closed to traffic and what remains today is an interesting example of landslide movement and repeated road reconstruction and repair (Figure 2, Figure 3, Figure 4, Figure 5 and Figure 6).
The landslide (Figure 7) itself is over 4000 years old and is a rotational landslide which has developed into a large debris flow at its toe (Waltham and Dixon, 2000). It is over 1000 m from backscarp to toe, has a maximum thickness of 30-40 m and the backscarp is over 70 m high.
Waltham and Dixon (2000) have divided the landslide into three distinct zones (backscarp area, transition zone and debris flow) according to their structure as follows:
The literature listed below give good accounts of this landslide in more detail.
Underlying the landslide are Dinantian limestones which are not included with the landslide (Waltham and Dixon, 2000). Overlying the limestone is the Bowland Shale Formation which consist of dark grey mudstone. The top of the landslide exposes the Mam Tor Beds. These are a sequence of turbidites of mudstones siltstones and sandstones.
Aitkenhead, N., Barclay, W.J., Brandon, A., Chadwick, R.A., Chisolm, J.I., Cooper, A.H. & Johnson, E.W. (2002). British regional geology: the Pennines and adjacent areas. 4th ed British Geological Survey, Keyworth, Nottingham.
Arkwright, J.C., Rutter, E.H. & Holloway, R.F. (2003). The Mam Tor landslip: still moving after all these years. Geology Today, v.19, pp.59-64.
Cripps, J. C. and Hird, C. C. (1992) A guide to the landslide at Mam Tor, Geoscientist v.2 (3), pp. 22-27.
Dixon, N. and Brook, E. (2007) Impact of predicted climate change on landslide reactivation : case study of Mam Tor, UK in Landslides : Journal of the International Consortium on Landslides, v. 4 (2) pp. 137-147.
Donnelly, L.J., (2006). The Mam Tor Landslide, Geology & Mining Legacy around Castleton, Peak District National Park, Derbyshire, UK, in Culshaw, M.G., Reeves, H., Jefferson, I. & Spink, T. (eds) Engineering Geology for Tomorrow's Cities, Proceedings of the 10th Congress of The International Association for Engineering Geology and The Environment, Nottingham, UK, 6-10 September 2006. Geological Society London(CD-ROM).
Doornkamp, J.C., (1990) Landslides in Derbyshire. East Midlands Geographer, v. 13 pp.33-62.
Rutter, E. H., Arkwright, J. C., Holloway, R. F. and Waghorn, D. (2003) Strains and displacements in the Mam Tor landslip, Derbyshire, England, Journal of the Geological Society of London v.160 (5) pp. 735-744.
Skempton, A. W., Leadbeaater, A. D. and Chandler, R. J. (1989) The Mam Tor landslide, north Derbyshire, Philosophical Transactions of the Royal Society of London, v. 329, No 1607, pp 503-547.
Walstra, J., Dixon, N. and Chandler, J. H. (2007) Historical aerial photographs for landslide assessment: two case histories. Quarterly Journal of Engineering Geology and Hydrogeology. V.40, Part 4, November, p315-332.
Waltham, T. and Dixon, N. (2000) Movement of the Mam Tor landslide, Derbyshire, UK, Quarterly Journal of Engineering Geology & Hydrogeology v.33 (2)pp.105-123.