Mam Tor - with Iain Stewart

On the Horizon fracking programme.

 

Posted with Blogsy

Mam Tor landslide - BGS

It's new year's eve and in a idle moment (acually all day at work today is an idle moment!) I was surfing the BGS website and found an interesting link to the landslide:

The landslide

The landslide 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:

1. The upper part of the slide material is a series of rock slices or blocks that were produced by the non-circular rotational failure of the original slope; most of these slices above the upper road show little sign of current movement
2. The central part of the slide is a transition zone, forming most of the ground between the two segments of road; it lies between the upper landslide blocks and the lower debris flow. It is composed of an unstable complex of blocks and slices, some of which can be identified by ground breaks along their margins; they overlie the steepest part of the landslide's basal shear, which was the hillside immediately downslope of the initial failure. The upper road lies along the highest section of the transition zone, which is currently the most active part of the whole slide.
3. Disintegration of the lower part of the slipped material has created a debris flow that now forms half the total length of the slide. This is described as a flow because it moves as a plastic deformable mass, but it may also be regarded as a debris flow slide because it has a well-defined basal shear surface.

The literature listed below give good accounts of this landslide in more detail.

The geology

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.

Further reading

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 SocietyLondon(CD-ROM).
Doornkamp, J.C., (1990) Landslides in Derbyshire. East Midlands Geographer, v. 13 pp.33-62.
National Trust: About Mam Tor, The Shivering Mountain (2009)
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.