Groups and Networks

East Midlands Regional Group meeting reports for 2015 are available below. Meeting reports dating back to 2000 can be downloaded on the right.

• Public Perceptions of the Geological Subsurface (14 July)
• Urban Renewal 2015 - 2020 - Costs and consequences of contaminated land (2 June)
• Roving on the Red Planet - Recent discoveries and future plans with the Curiosity Rover on Mars (11 May)
• Mineralisation in the Cheshire Basin (14 April)
• A Diet Fit for a King? - Isotope analysis of the remains of Richard III (10 March)
• The Current Status of Screening for Disposal of Radioactive Waste (16 February)
• AGM and Going Underground, Geology and Tunneling (27 January)

Public Perceptions of the Geological Subsurface

Meeting at BGS Keyworth Tuesday 14 July 2015

Report by Geoffery Jago

Our speaker at our meeting of July 2015 was Hazel Gibson who is a PhD student (Geoscience Communication) at the School of Geography, Earth and Environmental Sciences with Plymouth University.

Many people outside the field of geology have some grasp of the subject but when questioned, more often than not, their perception is found to be vague or mistaken. Realising the importance of conveying true information in geoscientific practice Hazel has inquired deeply into the problem.

In an experiment, to seek people’s visual perception of the subsurface, floor-standing models were made in the form of metre cubes with plain white sides and a coloured map of a landscape printed on the top. Volunteers were asked to sketch on the sides what they thought these vertical sections should show. The sketches ranged from very simple childlike ideas to a creditable solid representation from a cognoscente utilising more than one of the cube's sides. Hazel found that three-dimensional thinking, a key geological skill, was surprisingly rarely applied to geological thinking by the general population.

Hazel has studied numerous publications and held many discussions both with lay people and professionals in her research into what they understood about geology. She counted the frequency that certain words were repeated and laid out the results graphically with the type size of each word made proportional to frequency. Slides demonstrated the differences between professional and lay perceptions when describing geological features on surface and, separately, in the subsurface. When speaking of the subsurface especially, lay perceptions were generally vague. This work was analysed and presented in the form of relationship layout diagrams, some of considerable complexity.

Hazel’s dedicated work represents a very significant step in the important struggle to improve communication in the world of geoscience and she found intellectual skills lay almost wholly with professionals. Hazy geological knowledge blights not only the lay public, but is also found in non-scientifically trained decision makers, and this highlights a need for better education for all. Lack of grasp of sound knowledge is also a factor to consider when public objections are made to commercial geological operations.

With the satisfactorily sized audience, the presentation initiated a lively question-and-answer session where consultants in extractive and waste disposal operations figured strongly.

John Black completed this stimulating meeting by thanking the speaker.

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Urban Renewal 2015 - 2020 - Costs and consequences of contaminated land 

Meeting at University of Nottingham, Tuesday 2 June 2015

Report by Geoffery Jago

A welcome return speaker to our Group was leading expert on the study and remediation of building land Professor Paul Nathanail of the University of Nottingham and Director of Land Quality Management Ltd.

High on the government agenda is the need to find land to house people and businesses while protecting greenbelts. In the spotlight is brownfield land - plots which lie in or near urban areas, have been formerly wholly or partly used, are often part derelict, sometimes contaminated, but are potentially reusable.

The task of effective regeneration is to prepare places for people. With available funds shrinking, a developer is well advised to save money at the outset by careful research into all available information before commissioning new site investigation. He or she faces a bewildering task first to define the conditions and problems presented by a site and then to quantify profit or predict loss. Many, perhaps most, problems are not self-evident and the wise will seek experts at an early stage.

Cabernet Approach

Cabernet stands for Concerted Action on Brownfield and Economic Regeneration Network (see www.cabernet.org.uk). It is the European Expert Network addressing brownfield regeneration and provides a forum for different European Stakeholder Groups. Four people comprise the Anglo-German Co-ordination Team, one of whom is Paul.

To illustrate financial study of a project, Paul displayed a graph of value against cost showing that it could be divided into three areas: Cabernet A, where value was high against cost, (go for it), Cabernet C (the opposite - forget it) and, between them, Cabernet B (closer study, get more advice and see if there are any extra items which could add or diminish value).

Assessment Advice

From his experience Paul gave much useful advice including the following. One should avoid predicting both necessary remediation and profitability before all the information is to hand. There are dangers both in being too hopeful (false positives) and too pessimistic (false negatives). Every risk is specific to the site under study. Reading legal and Planning Authority rules should be a first step. Management can only succeed with thorough understanding.

Tobler’s law of geography states that “near things are more related than distant things”, so do not spread your study too far afield. Do not overspend money at the investigation stage but save it for the remediation stage. Begin with a qualitative rather than a quantative assessment. The numbers come later. Diagrams, which can all too often be neglected, are vital but cross-sections are better than contour plots, especially to the layman.

In writing your report, aim at the reader rather than the lawyer. Jargon can be useful if it is relevant and understandable. Use summaries, ensuring they are complete. When listing options, remember that to do nothing may sometimes be the valid one.

Smart Cities and the Way Ahead

Paul called for more fitting characterisation in local studies, with improved risk assessment embracing better integration of reclamation, remediation and redevelopment.

He invoked the concept of Smart Cities where all aspects of matters affecting people like homes, working places, services, traffic, messages and recreation were studied, one against the others, with the aim of improving the quality of life.

He said that geoscientists, as the only ones in the know, need to publicise their knowledge of potential sites. No one else can do this.

John Black thanked Paul for his stimulating and cutting-edge presentation

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Roving on the Red Planet - Recent discoveries with the Curiosity Rover on Mars

Meeting at British Geological Survey, Keyworth on 11 May 2015

Report by Geoffrey Jago

In November 2011 a rocket took off from Cape Canaveral carrying a spacecraft with a car-sized vehicle bristling with instruments. Its name was the Curiosity Mars Rover and by summer 2012 it was closing in on Mars. On 5th August a trailblazing procedure began to place Curiosity on the planet, climaxing in seven minutes of terror for the responsible team as they waited to see whether the vehicle had arrived safely via the innovative sky crane. It signalled that it was intact and within 2.4 km of its targeted spot.

At our May meeting our speaker was Professor John Bridges of the University. of Leicester, the Space Research Centre and Team Member of the NASA Mars Science Laboratory (MSL) Mission.

Professor Bridges’ richly detailed presentation, which began with an exposition of man’s scant knowledge of Mars before the space age, covered specific descriptions and illustrations of Curiosity, its instrumentation and the great range of areas of study that it has been able to sample and analyse so far.

The mission’s main goals are to learn about the atmosphere, climate, geology, the role of water and environmental conditions favourable for microbial life. The site chosen as having the best chance of revealing these secrets was the 155 km wide Gale Crater.
There is ample evidence of water erosion and deposition. A river bed, an ancient delta and lake deposits have been identified, all in the foothills of Mount Sharp, the 5.5 Km high central peak of the crater. In addition methane has been distinguished in Mars’ atmosphere and, for the first time on a planet other than Earth, X-ray diffraction has recognised hydrated minerals.

Curiosity’s ongoing journey has scrutinised a prodigious compass. The exacting effort continues to sift through the daily incoming myriad details of the history of Mars, its rocks, its water and its atmosphere.
 
Group Secretary Jo Thomas thanked Professor Bridges for his instructive and interesting presentation.

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Mineralisation in the Cheshire Basin

Meeting at British Geological Survey, Keyworth on 14 April 2015

Report by Geoffrey Jago, with the kind cooperation of the speaker.

The speaker at our April meeting was Dr Geoffrey Warrington DSc, CGeol, FGS, Honorary Visiting Fellow in the Department of Geology at the University of Leicester

The Cheshire Basin is an asymmetric graben formed by post-Variscan east-west extension. It extends from the Manchester area southwards to near Shrewsbury and contains a succession of Permian, Triassic and early Jurassic sediments. Triassic rocks include formations of the Sherwood Sandstone Group and the overlying Mercia Mudstone Group. The Sherwood Sandstone hosts a widespread barite mineralisation and localised copper-dominated polymetallic base metal deposits. The largest of these was mined at Alderley Edge and Mottram St Andrew, 25km south of Manchester. Smaller workings were at Bickerton, W. Cheshire, and around the southern end of the basin in N. Shropshire.

Dr Warrington has extensive knowledge of the geology and mineralisation of the basin and is an authority on the Alderley Edge mines which, with Clive Mine in N. Shropshire, he described as a prelude to an account of the composition of the mineralisation and its origin.

Alderley Edge is a prominent topographic feature comprising Sherwood Sandstone Group rocks lying between major N-S-tending faults in a horst crossed by several NW-SE-trending normal faults that downthrow NE-wards. The Edge has a north-facing scarp in which Wilmslow Sandstone Formation is capped by an erosion resistant unit at the base of the Helsby Sandstone Formation. On the south side of the Edge higher Helsby Sandstone units crop out successively SW-wards as their dip, in that direction, is steeper than the slope of the surface. Much of the succession is poorly exposed at surface and its features obscured weathering, but can be more fully seen in unweathered 3-dimensional sections in c.15 km of disused mine workings. The site is a Geological SSSI and the only one of its kind to be included in the Geological Conservation Review. Mining, which may have begun as early as the Bronze Age, ended in 1919. Between 1857 and 1878, the single most productive and economically successful period, acid-leaching of c.220,000 tons of ore containing c.1.5% Cu produced 3,202 tons of copper metal.

From E to W on Alderley Edge three sets of workings give access to mineralisation and its host rocks at three levels in the succession; each has individual features and none are representative of the whole site. In the east, in the small Stormy Point and Engine Vein mines, ores occurred in the topmost Wilmslow Sandstone and basal Helsby Sandstone. Lead ore (galena) occurs in the fault zones. Copper minerals were deposited in the footwalls, largely in aeolian deposits in the Wilmslow Sandstone, from fluids trapped updip against the faults and below mudstones in fluvial basal Helsby Sandstone deposits. Farther west, in the larger Wood Mine, facies control on the form and distribution of copper ore bodies hosted by fluvial fining-upward sedimentary cycles is evident. Mudstone beds at the tops of some cycles formed aquicludes that restricted fluid movement. At other levels the debris from penecontemporaneous erosion of such beds occurs in sandstones and formed only partial barriers to fluid movement. In contrast, in West Mine, the largest and most westerly mine, large and extensive bodies of copper ore formed in a relatively homogeneous aeolian host rock with no significant aquicludes.

In north Shropshire mineralisation is associated with N-S-trending faults and occurs in beds that dip N-wards beneath the Mercia Mudstone and are equivalent to the Helsby Sandstone at Alderley. Clive Mine is the main accessible example; copper and some cobalt minerals were deposited in aeolian sandstones in the hanging wall of a fault and immediately below a seal formed by Tarporley Siltstone Formation at the base of the Mercia Mudstone. Notable at this locality are ‘pepper and salt’ rock, a white sandstone with speckles of black cobalt and manganese minerals, and prominent liesegang which record stages in movement of fluids.

We were shown many good photographs of the workings at Alderley and Clive, and of the mineralisation and its host rocks in an unweathered state. Secondary copper minerals, coloured green and blue, and galena are visible in situ. Specimens of these from Alderley, and ‘pepper and salt’ rock from Clive, were available for examination.

The base metal mineralisation is dominated by Cu; primary species were sulphides of which, apart from galena, only traces remain. The majority of the species recorded are secondary and include hydrated arsenates, carbonates, silicates and sulphates. Many are complexes of Cu, Pb, Zn and Fe with elements such as Al, As, Co, Mn, Mo, Ni and V; Ag and Hg sulphides, Ag selenide and Au are recorded. Mottramite, a hydrated Pb-Cu-vanadate, was named for Mottram St Andrew, the site near Alderley Edge where it was discovered and which was the source of material used to determine the valency of vanadium. However, some consider the type material to be from Pim Hill, near Clive Mine in N. Shropshire.

The mineralisation was originally regarded as syngenetic, or deposited contemporaneously with the host rocks. However, from the 1960’s it has been regarded as epigenetic, or introduced after deposition of the host rocks. In 1977 the speaker proposed that the Alderley deposit resulted from the migration of chloride-rich intrastratal brines into a structural trap formed by the Alderley horst where metallic ions leached from minerals in sediments the brines had passed through were deposited in a reducing environment, possibly created by hydrocarbons that followed the same pathway.

This basic concept has been adopted and developed by subsequent workers. The first paragenesis was proposed in 1972 and was followed by a more complex, four-stage process in which a relationship of mineralisation to diagenesis was emphasised. In 1989 a fluid inclusion study confirmed that the mineralising fluid was a low-temperature basinal brine and a sulphur isotope study indicated derivation of sulphate from evaporites in the Mercia Mudstone. The structural trap scenario requires the host rocks in the Alderley Horst to have been covered by a seal of Mercia Mudstone; that occurred during the Anisian (early Mid Triassic), giving a maximum age of c.245 Ma for the start of mineralisation. A suggestion has been made that mineralisation occurred during late Mesozoic burial or Tertiary uplift but in 1999 BGS workers proposed an earlier age and a complex metallogenesis. This involved mobilisation of metals by breakdown of parent minerals during early (eodiagenetic) diagenesis, followed by a complex mesodiagenesis that initially involved sulphate-rich brines expelled from the Mercia Mudstone producing an anhydrite cement in the Sherwood Sandstone. Subsequently metalliferous brines migrated into fault structures and mixed with reducing fluids causing precipitation of a polymetallic assemblage during latest Triassic to Early Jurassic times. The assemblage was extensively altered during a late diagenetic (telogenetic) phase, after post-Cretaceous inversion of the Cheshire Basin.

The following contributions by Dr Warrington expand on this summary and provide references to further sources:

• 2010. Mineralization in England and Wales. Geological Conservation Review Series 36: 182-190. Peterborough: Joint Nature Conservation Committee.
• 2011. Mineralization in Triassic rocks of the Cheshire Basin with particular reference to Alderley Edge, Cheshire, and Clive, Shropshire. Proceedings of the Shropshire Geological Society 17: 33-39 
• 2014. Inside Mid-Triassic fluvial deposits: a legacy of mining sediment-hosted ore bodies in Cheshire, UK. Proceedings of the Geologists’ Association 125: 548-559

The Chairman, John Black, thanked Dr Warrington for an interesting and well illustrated lecture.

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Diet Fit For a King? – Isotope analysis of the remains of Richard III

Meeting at British Geological Survey, Keyworth on 10 March, 2015

Report by Geoffrey Jago
 
“Nothing brings the dead more vividly to life than finding out what they ate. It makes the famous seem more human, and shines a light on the obscure.”
    from “The QI Book of the Dead” by John Lloyd and John Mitchinson,

Our speaker at our March meeting was Dr Angela Lamb of the Natural Environment Research Council’s Isotope Geosciences Facility.

When in 2012 a skeleton was unearthed from below the long demolished Greyfriars Friary in Leicester, tests left no doubt that these were the remains of King Richard III. With the news stands rocking with this story the media developed an instant thirst for any particulars of what the King was like and how he had lived. The research by Dr. Lamb and her associates at BGS and the University of Leicester has provided a surprising compendium, all of world wide interest.

Isotopes Reveal Their Secrets

Most elements occur as two or more isotopes which are chemically identical but have different masses owing to their carrying differing numbers of neutrons, rather like excess baggage. Nature has left important messages in the proportions of each isotope in a sample because they vary with place and lifestyle. Key elements include hydrogen, oxygen, nitrogen, carbon and strontium contained in bones and teeth. This way, much has been learned of how the king lived his 32 years.

Sampling

Sampling began very soon after the bones were found. Richard’s teeth as shown on Dr. Lamb’s slide are notable for their lack of dental decay. An upper molar and lower premolar were sliced longitudinally for examination. Once formed, the isotope composition of the elements within teeth does not alter and these samples were chosen as evidence of conditions from age 3 to 14.

In contrast, bone is in constant reconstitution, so recording a average range of conditions over time. The team studied fragments of a left rib and right thigh bone. Clues were obtained from key elements derived from the food, water and wine that passed the subject’s (or in this case the regal) lips. Data from other skeletons of similar age, notably from York and the long deserted village of Wharram Percy thirty kilometres to the east of York, upholds the conclusions drawn from the king’s bones.

An Oxygen Map

Oxygen in air and water occurs mainly as two isotopes which the westerly prevailing UK winds winnow to an extent that it has been possible to draw a contour map of the isotope proportions.

Comparing this information with oxygen in bones that formed at different ages has shown that Richard aged up to seven lived for a time in a westerly region like the Welsh borders and then moved eastwards, consistent with his known years in Wensleydale.

Strontium

Strontium in tooth enamel ingested from food and water builds a bodily record of local farming geology. This tells us the general area where Richard lived up to age 7. The proportions of two isotopes of strontium in rocks in England differ between the Pennies and younger rocks further south and this agrees with studies with other elements.

Food and Drink

Nitrogen and carbon isotopes reflect diet, via measurements from collagen, the body’s tough connective tissue.

Much has been learned of what Richard had eaten and drunk. A high status medieval diet is indicated with a trend from terrestrial to marine food. This typically included bread, ale, wine, fish, meat and spices. The team studied how religious fasting rituals and eating were likely to bias what a wealthy person ate. Later in life Richard’s fare spanned freshwater fish like eels, pike and carp and wild fowl including bitterns, swans and egrets.

What else might affect oxygen isotope ratios? Medieval wines were dictated, as today, by source of grapes so samples of wine made from four different types of grapes were tested to chart this ratio in each. Apparently not one to stay unnecessarily sober, the ratio in Richard’s rib bone suggests a quarter of his fluid intake could have been wine. Nor was he loth to remain hungry. We were shown the prodigious menu of his coronation feast to which he invited 3000 guests.

And Finally

Dr. Lamb ended by displaying a press headline “Egrets - I’ve had a few”. Had Richard not been been such a stalwart trencherman and wine fancier this account would have added “But then again - too few to munch on”.

John Black spoke to thank Dr. Lamb for this interesting insight into the application of science to history.

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The Current Status of Screening for Disposal of Radioactive Waste. 

Meeting at British Geological Survey, Keyworth on Monday 16 February, 2015 

A large audience attended our February meeting to hear Professor Bruce Yardley, Chief Geologist of Radioactive Waste Management Ltd. (RWM), speak and invite discussion on the especially important subject of how the nuclear industry must decide on a safe permanent home for its radioactive waste.