Geologically, the rocks of the East Midlands range in age from the Pre-Cambrian Charnian Super Group found south west of Loughborough, to the Quaternary Holocene deposits found as alluvium in modern river valleys and as landslide deposits on slopes formed mainly of Carboniferous or Jurassic rocks. The lithostratigraphy of the East Midlands is summarised in Table 1.
The main geohazards relate to the collapse of old workings for lead ore and gangue minerals, limestone, coal and gypsum, reactivated or first time landslides and failures of cuttings or the walls of quarries and opencast workings. There are also potential contamination and stability problems associated with rising minewater levels following the decline of mining in the region.
Poor foundation conditions are found in the infilling deposits of the major river valleys, such as the Trent. Determination of the depth and extent of weathering (largely periglacial) of pre-Quaternary deposits is also important.
Other problems relate to the continuing need to extract minerals to support development. These include the extraction of limestone from the Dinantian (Carboniferous Limestone) of the Peak District of Derbyshire, gypsum from the Mercia Mudstone of south Nottingham- shire, sand and gravel from, for example, the Trent Valley, and aggregate from the hard, strong Charnian rocks of Charnwood Forest in Leicestershire Extraction of these deposits provides potential environmental conflicts for local communities.
The decline in the deep mining of coal in Derbyshire, Leic- estershire and Nottinghamshire and the increase in opencasting has increased concern about loss of jobs and environmental degradation in these areas.
Sylvester-Bradley and Ford (1968) edited a classic volume on the geology of the East Midlands while Firman and Lovell (1988) discussed the engineering and environmental geology of the greater Nottingham area.
Hobbs et al (1998) have described aspects of the engineering geology of the Mercia Mudstone.
Professor Martin Culshaw, British Geological Survey
Firman, RJ and Lovell, MA. 1988. The geology of the Nottingham region: a review of some engineering and environmental aspects. In:
Bell, FG, Culshaw, MG, Cripps, JC and Lovell, MA (eds). Engineering geology of underground movements, Engineering Geology Special Publication No 5, 33-51. Geological Society, London.
Hobbs, PRN, Hallam, JR, Forster, A, Entwisle, DC, Jones, LD, Cripps, AC, Northmore, KJ, Self, SJ and Meakin, JL 1998. Engineering geology of British rocks and soils - Mercia Mudstone. British Geological Survey Technical Report WN/98/4.
Sylvester-Bradley, PC and Ford, TD (eds). 1968.
The Geology of the East Midlands. 400p. Leicester University Press.
Unscrambling airfield data
Work at Nottingham Trent University has developed a geographical database about disused military airfields in the UK with a special focus on the East Midlands standard region.
During the Second World War the East Midlands had 106 active airfields.They covered more than 1% of the region's landmass, mostly at the expense of arable farming.A wide range of geological formations were incorporated, with the notable exception of high-compressibility Holocene fen peats and alluvium.The greatest clustering of permanent aerodromes was on the plateau of the Middle Jurassic Limestone, but in wartime many stations were constructed on Quaternary till and fluvioglacial sands and gravels.
Today, only six RAF airfields remain active in the region, clustered in south Lincolnshire.With six decades of operation by heavy bombers and subsequently jet training aircraft, these establishments are obvious sources of land contamination and other geohazards.
They also have an impact on the landscape and heritage of the region.
Planned regeneration of abandoned airfields such as Binbrook, Scampton and Swinderby must involve professional geologists, geomorphologists and ground engineers.
The project is focusing on the assistance to land-use planners, conservationists and developers that geologists can give to remediation.
RNE Blake Geohazards Research Group, The Nottingham Trent University
Breaking the surface
Nottingham's city centre is riddled with about 500 artificial caves at shallow depth in theTriassic Sherwood Sandstone. A few are old sand mines, but nearly all were dug out as a lower cellar level beneath houses, factories and pubs.
Most of the caves are abandoned, and half are unrecorded, making them a major building hazard. Typically caves are 1m to 3m below the top of the rock surface and are up to 5m wide. Sensibly under these circumstances, local building regulations demand that every column base etc is probed to prove solid rock for 3m when loadings are relatively light, and 5m for heavy loads.
The approach is a little over-cautious in many cases, but roughly appropriate.
There have been a few road collapses, and on-site breakthroughs, but no buildings have disappeared - yet.
The city also boasts the impressive Nottingham Castle which stands on a crag of Sherwood Sandstone close to the centre. Chunks fall off at intervals; a big rockfall once took out part of the castle walls, but most are smaller and largely due to tree root action.
Many old houses are built on too-shallow footings on the alluvial clays of the River Trent. Subsidence problems are widespread, typically triggered by small ground movements breaking shallow drains. The same problem applies to a lesser degree in the weathered profile in the Mercia Mudstone.
Mining subsidence is less of a problem than it used to be, but localised damage occurs over open fissures in the Magnesian Limestone and the Sherwood Sandstone over the concealed coalfield. The problem is worst around Mansfield, notably where the Magnesium Limestone is cambered at scarp edges.
Gypsum dissolution is problem in the Triassic. The gypsum bands are thin and there have been few sinkholes, but significant bridge foundation problems were encountered on the new Derby bypass when the gypsum was found to be halfgone at outcrop.
Stretching the boundaries of the East Midlands, Mam Tor at Castleton in the Peak District is one of the best examples of an active landslide in Britain. The A625 trunk road has been closed since 1978, and the Carboniferous shales still moves at mean rate of 0.25m/year. Movements are periodic, typically with 1m of movement occurring in years when rainfall passes a one in four year threshold. A landslide on Bolsover's scarp of coal measure shales capped by Magnesian Limestone reactivated a few years back and took out 10 houses.
Other slope stability measures are associated with soliflucted slopes, which the area has in abundance, a legacy of periglacial activity throughout the Devensian. Carsington proved the point rather expensively.
Tony Waltham Nottingham Trent University
The Land Quality Management group at the University of Nottingham is working with a number of local authorities in the East Midlands to develop their inspection strategies under Part IIa of the Environmental Protection Act 1990.
The strategies need to reflect local conditions such as industrial history, topography, current land use patterns and of course geology. Geology is being considered in terms of its potential to act as a source of contaminants, a pathway or a receptor.
Land Quality Management at the University of Nottingham is also working with The Sherwood Energy Village to characterise land adjacent to the former Ollerton Colliery site.
The colliery site is being redeveloped with EC funding and will comprise residential, commercial developments and open space.
LQM's site will be used to assist insitu research in assessing and remediating contaminated land before being ultimately redeveloped as a railway station.
East Midlands offers a range of geotechnical and engineering geology related study options at both undergrade and postgraduate level. Both Nottingham Trent University and University of Nottingham offer well thought out masters courses, with each offering unique learning options.
Masters courses Nottingham Trent University MSc in geotechnical engineering design and management The part time course has been running successfully at Nottingham Trent University since January 1998. There are currently more than 40 delegates enrolled on the programme which is proving particularly popular with industry.
The strength of the EPSRC IGDS supported programme is in providing what the delegates and their companies are looking for within a sound academic framework, believes course leader John Greenwood. Most of the modules are run over a six or seven week period with delegates attending the university for two weekends. In this way, absence from the place of work is minimised.
The maturity and experience of the delegates is recognised and wherever possible individuals are able to contribute their particular knowledge and experience to the module discussions.
Currently more than 25 different firms are represented among delegates and many have made great use of the contacts made during the attendance periods. They also benefit from contact with the specialist academic and industrial contributors to the modules.
Technical modules are supplemented by specialist topics om contaminated land, ground improvements and retaining structures.
Management related modules cover project planning, contract procedure, safety, and construction law.
Leading industrial specialists provide the practical perspective to each module with contributions from the nearby British Geological Survey.
University of Nottingham MSc in contaminated land management An EPSRC IGDS sponsored course aimed at giving those working in industry or regulation state of the art understanding of how to investigate, assess, and remediate land contamination.
MSc environmental engineering Provides advanced training in environmental engineering Continuing professional development Modules from the MSc contaminated land management can be attended as stand alone short courses.
Additionally the Land Quality Management group offers short courses in risk assessment, engineering geology, slope stability, GIS, site inspections and many other topics.
Undergraduate Undergraduate courses with significant geotechnical and engineer geology input include MEng, BEng and BSc civil engineering and related courses at Nottingham, Nottingham Trent and Loughborough.
BSc geological engineering at Nottingham Trent.
BSc applied environmental earth science at Derby