The ground beneath our feet:
 200 years of geology in the Marches

 Thursday 13^th September 2007

 Ludlow Assembly Rooms

Hosted by the Shropshire Geological Society in association with
the West Midlands Regional Group of the Geological Society of London

Abstracts

Click here to view the programme schedule.

Opening Session

Prof Michael Rosenbaum, Chair of the Steering Group of the Marches Festival of Geology

Welcome Address

The Ground Beneath Our Feet

Rocks represent our main source of evidence for interpreting the past, and the Marches include representatives from all twelve internationally recognised periods of geological history, from the Precambrian to the Holocene, spanning 700 million years of earth history. Included within these are four which were defined on the basis of the evidence discovered here: Cambrian, Ordovician, Silurian, Devonian, and a fifth, the Permian, was subsequently defined on the basis of techniques first worked out in the region.

One of the reasons that the area is so interesting and varied is that it is a geological "frontier zone". For instance:

• The Malvern Fault, running North South, represents an ancient and fundamental division that has asserted considerable influence through time, at the join between two small Precambrian continents.

• The Church Stretton Fault/Neath Valley Disturbance and the parallel Pontesford/Linley Fault, both running North East to South West, form the boundary between areas of Caledonian folding to the west and relatively undisturbed, older continental crust to the east. It was a major plate boundary during the Silurian.

• The Pleistocene Ice Sheets encroached the lower ground, but probably left the hill tops ice-free, creating a complex local topography that includes hummocky terrain as moraine accumulated beneath the ice or was dumped as the ice melted, along with considerable disruption to the drainage system, diverting rivers, flooding valleys and eroding new landscapes.

Our current level of understanding of the 700 Ma evolution of the Marches is based upon detailed evidence acquired through diligent collecting and recording by generations of enquirers. Its interpretation is due to the skills that geologists are able to employ to read it. However, many questions remain unanswered, awaiting discovery of new facts and interpretation, or re-interpretation, as new ideas emerge.

The impact of our understanding of the ground on the lives of those who live in the area is considerable. The industrial revolution began here, with ironstone nodules brought down from Clee Hill to be smelted at Burrington using charcoal. This was followed in Broseley and Coalbrookdale by ironstone and limestone being fired with coal and an upsurge in industrial output along the banks of the River Severn in Ironbridge Gorge. Mineral extraction is still active, nowadays primarily for construction and roadstone; the groundwater is a major concern both to domestic consumption and agriculture; the landscape attracts tourism, arguably now the most important source of income, and its configuration determines the potential for sustainable development of the region.

On a local level, the public understanding of geological science has been developed most notably by the work of the late John Norton, who had a remarkable gift for encouraging youngsters to take an interest in the ground around them. This has been one of the reasons that the area has been portrayed as "The Geological Capital of the UK" (Wikipedia) and many have felt this should be reflected in the Bicentennial Celebrations of the Geological Society of London. A number of organisations in the Marches have therefore agreed to collaborate to run a festival to celebrate the Societys 200th anniversary.

The one-day symposium in Ludlow is at the centre of this Festival, on the theme of "The ground beneath our feet: 200 years of geology in the Marches".  This focuses on the following five themes of general as well as regionally significant interest.

Dr Peter Toghill, Vice Chair of the Shropshire Geological Society

Marches Geology for All - an introduction to 700 million years of earth history in Shropshire and Herefordshire

It might come as a surprise to find that the story of 700 million years (the age span of the rocks in Shropshire) could change significantly in a mere 25 years. Of course, the geology has not; it is a reflection of the complexity of the Countys long evolution that the interpretation of that geology should be reassessed, and new conclusions should be drawn in the light of more research, both at home and abroad.

Sun-parched deserts, tropical rain forests and exotic coral reefs - fossilised evidence of all of these and more can be found in Shropshire. The County has one of the most varied geological landscapes in the world as a result of the movement of its landmass from the Antarctic Circle to its present location.

From Geology of Shropshire, 2nd edition. Copyright Peter Toghill

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Session 1: The mark of distinction: local character shaped by landscapes and building stones

Dr David Lloyd MBE, Research Advisor and former Chair of the Ludlow Historical Research Group

Local character shaped by landscapes

In 1770 the English landscape painter Paul Sandby, with his patron Sir Watkin Williams-Wynne of Wynnstay near Ruabon, and accompanied by his nine servants, fifteen horses and a large cart, visited Llangollen, Bala, Dolgellau and Caernarfon.

This provides a flavour of the portrayal of the landscapes of The Marches seen through the works of great artists, providing an insight of the region as seen by the pioneer geologists and often revealing details of the ground that have since been lost, or features whose importance might otherwise be overlooked.

The mid 19th Century sketch of Ludlow and the River Teme drawn by Charlotte Murchison, wife of Roderick Murchison (later Sir), probably drawn during her first visit to Ludlow, in 1831, and used on page 195 of The Silurian System (published 1839) to introduce Chapter 16 of the same name. This was reproduced as the frontispiece of the 1974 (No.21) Bulletin of the Ludlow Research Group. However, field evidence actually shows the beds to be dipping in the opposite direction at this point! Perhaps Charlotte merged two separate views to enhance the aesthetics, one of the church and castle looking east towards Titterstone Clee (the prominent hill in the distance), and another of the rocks exposed along the Bread Walk near the last major building stone quarry to have exploited the calcareous siltstone of the Whitcliffe Beds, some 300-400 m to the south (right) where their inclination is indeed to the right, as depicted here. In between lies the core of the Ludlow Anticline.

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Andrew Jenkinson, Countryside interpreter and Projects Officer for the Shropshire Geological Society

From the Ground, Up: vernacular building stones in a border landscape

Many parts of Britain are characterised by their building stones: the Jurassic Limestone of the Cotswolds, flint of the chalklands of the south east, gritstone of the "the north". But look at a vernacular architecture map of Britain and the chances are it will show Shropshire, along with Cheshire to the north and Herefordshire to the south, as "black and white" or timber-framed country. In practice stone buildings are more common than timber-framed ones in most parts of the county prior to the mid-nineteenth century, but this is not recognised as the general perception because there is no single characteristic stone.

Instead we see extensive use of local stone which mirrors the huge variety of different rock types across the county. A few Shropshire stones had structural qualities which made them very suitable for building, notably the freestones of the north Shropshire hills, and in particular Grinshill. Their reputation ensured a wide market. But the most interesting are those of very restricted outcrop, used of necessity, but only in the immediate vicinity of the quarries. Examples include Alberbury Breccia, Acton Scott Limestone, the Pentamerus Sandstone or Bog Quartzite of Norbury and Wentnor amongst others. These are the stones which give local distinctiveness to individual villages or estates. But others equally reflect the local geology from the almost Cotswold-looking calcareous siltstones of Corvedale to the Carboniferous Limestone of Llanymynech.

This talk will range across the county, looking at the way in which the vernacular buildings can be read as a geological map, and considering the importance of recognising and conserving this degree of distinctiveness in restoration of stone buildings.

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Session 2: The Marches in the past: on the edge of a lost ocean

Dr Robin Cocks OBE, former Keeper of Palaeontology at the Natural History Museum, London, and President of the Geologists Association

Palaeogeography of the Lower Palaeozoic

It is natural for us all to assume that Britain has always been the sea-girt isle beloved of Shakespeare. However, as soon as one starts to look at British rocks and to understand her geology it becomes progressively obvious that, since the rocks contain numerous and varied fossils of marine origin, these islands have been under the sea for a very large part of geological time. For these reasons, Britain is one of the best places in the whole world in which to study geology, since the rocks represent a large proportion of Earth history, with every period from the Precambrian to the Holocene represented by sediments and fossils. Shropshire emulates much of this within the compass of a single county.

However, it is also natural to assume that the area now occupied by the British Isles has always been together as a single unit, if not always at present day latitude and longitude. Once again, a fallacy, and it is the chief purpose of this relatively brief review to describe how the disparate parts of these islands have come together, with particular reference to their amalgamation in the Palaeozoic. For, since the Palaeozoic, all the area of these islands has been joined together as a single unit and, thus, although the seas have advanced and retreated many times in the Mesozoic to Recent, the changes in palaeogeography during the last 250 million years have been much less fundamental than in the previous aeons.

The past forty years have been a most exciting time for geologists: despite the preceding 200 years of steady progress in geological knowledge, it has only been since the 1960s that geology has possessed the unifying theory of plate tectonics, comparable to that of evolution for the biological sciences.

The effects of that global knowledge on our understanding of the geology and history of the British Isles have been astonishing. Most dramatically, we now know that Britain was divided between two major terranes until the Caledonide Orogeny of the Silurian and has thus only been united for less than 10% of geological time.

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Prof David Siveter, Professor of Palaeontology and Chairman of The Micropalaeontological Society, University of Leicester

The Silurian Herefordshire Konservat-Lagerstatte: a unique window on the evolution of life

Our understanding of the history and biodiversity of life on Earth relies on the fossil record, and especially on information gained from rare cases of exceptional preservation, where the soft parts of animals and even entire soft-bodied animals are preserved. The recently discovered Silurian Herefordshire Konservat-Lagerstatte is one such deposit, and it is emerging as an exciting palaeontological discovery of global importance. It contains a variety of small marine invertebrates such as worms, molluscs, starfish, and brachiopods, together with a range of arthropods, plus many intriguing forms of yet unknown affinity.

All of the fossils are beautifully preserved in extraordinary detail and in three dimensions. They occur as calcite in-fills within nodules entombed in an ancient volcanic ash that fell onto a shallow sea floor some 425 million years ago. The soft-bodied animals that became preserved are unknown from anywhere else in the world.

A small team from Leicester, Oxford, London and Yale universities has been working on these amazing fossils since the discovery of the biota. The Herefordshire fossils cannot be extracted from the rock nor fully studied by conventional means. Instead, they are captured digitally and reconstructed in 3-D as "virtual fossils" using computer techniques. The computer reconstructions can even be turned into physical models of the animals through the use of rapid prototyping technologies.

The Herefordshire animals are from a period of geological time for which we have hardly any information about soft-bodied faunas. This remarkable fauna from the Welsh Borderland is therefore crucial in helping to fill a gap in our knowledge of the history of life and to resolve controversies about the relationships of animals still alive today.

Phyllocarid (a shelled arthropod, among the earliest animals with a hard shell) from the Herefordshire Konservat-Lagerstatte copyright David Siveter 2007

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Session 3: Geology in the community: evolving perceptions and realities

Harriett Baldwin, Parliamentary Candidate for West Worcestershire, and Philip Dunne MP, Member of Parliament for Ludlow (in absentia)

Geology in the community: evolving perceptions and realities

Earlier this year (2007) the Government missed an opportunity to protect the 57 Sites of Special Scientific Interest in the Ludlow constituency; there are a further 55 elsewhere in Shropshire. New rules, required under the Environmental Liability Directive (ELD), provide a minimum standard of protection by holding companies liable for polluting the environment.

The ELD covers environmental harm that may arise from certain hazardous activities including the use of genetically modified organisms (GMOs), waste disposal and the discharge of pollutants to water. The Governments plans for England exclude most wildlife species recognised as requiring protection, 375 in total, and over 3,000 SSSIs.

The intention of the ELD is to introduce the "polluter pays" principle. By making businesses financially and legally accountable for any environmental damage they cause, they will be more cautious about what they do. It should prevent environmental harm and, if that does not work, the costs of putting things right should be borne by those causing the damage.

The proposed legislation has two loopholes which could enable companies to avoid financial liability for damaging the environment. The "permit defence" would allow companies to avoid liability if they had been granted a licence for what turned out to be damaging activity, and the "state of the art defence" excuses pollution if scientific knowledge at the time did not predict the potential harm. This may lead to inadequate research into side-effects, and allow polluters to continue to pollute. It will be the taxpayer who will have to pick up the bill.

A broader role of national government concerns its lead on combating climate change. Here there is opportunity for technical innovation, leadership and pump-priming for technological solutions. There are various examples of Government putting their toe in the water and trying to introduce market solutions by means of pump-priming, but the results have been disappointing.

Science has a big part to play in these matters. British companies are innovative and keen to take advantage of whatever pump-priming the Government are prepared to put in place. They are willing to meet the regulatory burdens placed on them in the search for alternative solutions, and a regime is needed to encourage the practical implementation of ideas arising from the scientists imagination, an essential aspect of enabling enterprises to get going.

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Prof Hugh Torrens, Emeritus Professor of Historical Geology, Keele University

Geological pioneers in the Marches: from Robert Townson (1799) to Roderick Murchison (1839)

Shropshire provides a birthplace for the worlds Industrial "Revolution", from the early 1700s. This had used Shropshires abundant, and varied, geological materials; like coal, iron ore, pitch/oil, and its various limestones and clays. Most commentators have however seen the rise of geology in Shropshire as much later, dating only from 1839, when Roderick Murchison, the "King of Siluria", ordered the countys rocks in print in his The Silurian System and described its wondrous geology.

The truth is more complex. There was much geological activity here before Murchison, much of it inspired by its early industrialisation, with a number of often fascinating figures. These include the sadly forgotten, and Cardington-based, Robert Townson and two Darwins. Residents and visitors have included James Hutton, the supposed "father of modern geology", and two important members-to-be of the worlds oldest Geological Society, that of London, founded in 1807. One was soon to guide William Buckland on his first ever field trip and the other produced the first properly geological publication (and on Shropshire) which that Society ever produced, both in 1810.

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Prof Rod Stevens, Professor of Quaternary Geology, University of Gothenburg, Sweden

Challenges for the geoscientist: an international perspective

Science communication is a challenge at all levels of society, and essential if we are to maintain or increase our impact concerning important issues.

Science communication is, Rod suggests, seldom effective if kept at the beginning of the continuum: ?information ? interaction ? integration?, which can be used to describe the interface alternatives between science and society. A few diverse examples will be used of some successful and some questionable applications of geoscience knowledge. Also, the role that community contact has had in these examples is of interest.

One of the most alarming facts today is that the dependent relationship between science and society is often not apparent to those that are most important for our future: decision-makers and youth.

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Session 4: The Ice Age: on the edge of a glacier

David Pannett, Field Meetings Officer for the Shropshire Geological Society

The Ice Age Legacy in North Shropshire

Glaciations in the Severn Valley are a neglected aspect of the Ice Age story, overlooking the contribution by Welsh Ice. Over the last 200 years our ideas have developed, with four discernible phases: (1) observations in Georgian times whilst constructing the new road network, but failing to understand their meaning; (2) gravel pits visited by Darwin and others in early Victorian times, discovering sea shells; (3) Lake Lapworth in the 20th Century, flooding and waning, preventing others from appreciating the landforms since the whole area was supposed to be at the bottom of a vast lake; (4) at the beginning of the 21st Century a realisation of glacial complexities, notably the roles of subglacial valleys and non-stationary ice fronts.

The landscape is telling us its story, through its elevations, angles and deposits, but how can we reveal it?

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Dr Andrew Richards, Herefordshire and Worcestershire Earth Heritage Trust

The Ice Age in the Marches: Herefordshire

The Welsh Borderland has been subject to at least two phases of widespread glaciation and significant river system development over the last half million years. The latter has received very little attention over the past few decades. This talk aims to look at the response of river systems in Herefordshire and the surrounding area to environmental change during the Quaternary. It will provide an introduction to the complex causes of change in river behaviour, looking particularly at the longer term development of fluvial landscapes in the region. The overall aim is to draw attention to the need for more research in this aspect of the landscape, necessary for a full appreciation of the recent geological history of this fascinating region.

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Session 5: The future for geology in the Marches

Prof John Dewey FRS, UC Distinguished Professor of Geology, University of California Davis

Future avenues of research in the Welsh Borderland

Johns goal is to relate the detailed structure of extant and extinct plate boundary zones to present and past relative plate motion. He is especially interested in rock fabric evolution and block rotation and deformation in transtension (oblique extension) and transpression (oblique shortening).

Why should the general public be interested in what John does? This work concerns fundamental questions of rock behaviour under varying pressures and temperature conditions; this basic research contributes to an understanding of geohazards, such as earthquakes and landslides.

Forty years of research has led to more and more excitement about finding out how the Earth works. For each question answered, five new problems emerge! Research is the most interesting thing that a scholar can do. Also research makes one a better teacher. In terms of personal achievement, John has worked out a scheme for understanding sea level changes over long and short periods of time. He discovered how oblique convergence 420 million years ago in western Ireland and oblique divergence 400 million years ago in Norway explain rock structures and fabrics.

Within the Marches there are ancient plate boundaries and hidden within these are new facts to be discovered and theories to be evolved to help explain ?the ground beneath our feet?.

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Dr David Schofield, British Geological Survey Regional Geologist for the West Midlands and the Marches

The future for geology in the Marches: a BGS perspective

Our understanding of geology has a considerable impact on the lives of those who live in the area. Mineral extraction is still important to local development, groundwater is a major concern for both domestic consumption and commercial use, the landscape attracts tourism and its configuration determines the potential for sustainable development of the region. It is the responsibility of the British Geological Survey to maintain and develop the nation?s understanding of its geology to improve policymaking, enhance national wealth and reduce risk.

The BGS has a long history of geological study in the Marches starting in the 1830?s with the work of Sir Henry de la Beche and Sir Roderick Murchison who oversaw the original one-inch geological survey of the area. The current phase of work by the BGS started in the mid 1980?s and has largely been driven by the requirement to complete 1:50 000 scale geological map coverage of Wales and the Borders.

Current work in the Dinas Mawddwy district aims to produce the first 1:50 000 scale geological map of this area and develop scientific collaboration with university researchers interested in palaeoenvironmental controls on Llandovery-Wenlock sedimentation. We hope soon to commence surveying of the Knighton district, and to use this as a basis for reappraising the geology of the adjacent Ludlow Anticline itself. We will also begin a programme of collaborative studies in the Wem district, part of the North Shropshire Plain, focusing on developing sediment/landform assemblage models aimed at elucidating ice marginal processes and the history of deglaciation after the last, Late Devensian glacial maximum.

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Closing Address

Lawrence Banks CBE, Great Grandson of Richard William Banks who hosted Murchison at Hergest Croft on his epic visits to the Marches

It was Richard Banks (1791-1871) who was one of the guests at a seminal meeting in July 1831 at the home of Thomas Frankland Lewis MP, Harpton Court. Present were the ?Border Squires?, families of some social standing in Radnorshire, with whom Banks had become linked by marriage in 1817. This was the occasion which fired Murchisons enthusiasm for geology, inspired by their recollections based on personal collections of fossils and the character of the strata from whence they had come. It was also on this occasion that Lewis son, George Cornewall Lewis (1806-1863), Murchison later acknowledged as being the first to urge him to compile the geological records of the region, the work that was to become The Silurian System.

The role of the local clergy and gentry in supporting the scientific forays of visitors such as Sir Roderick Murchison, in turn advancing our knowledge of natural science, is perhaps far greater than generally acknowledged. Research for the paper by Sinclair & Fenn in the 1999 Radnorshire Society Transactions (pages 143-172) Geology and the Border Squires, was based largely on papers in the private library of the Banks family, lodged at Hergest Croft. This reveals the significant assistance that was afforded, scientifically, financially, and socially. Indeed, this research indicates that it was an ancestor of Thomas Frankland Lewis MP of Harpton Court, Thomas Lewis MP (1690-1777), also of Harpton, that had leased a farm constructed using the local (Silurian) limestone. The farm was, and is still, called Siluria. Their thesis is that here lies the true origin of the world-famous period of geological time, named in deference to Murchisons sponsors rather than a long-lost Celtic tribe.

Long may the spirit of the local amateur live on in organisations such as the Shropshire Geological Society and the Woolhope Naturalists Field Club, encouraged by the Geological Society, now entering its third century.

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Responsibilities and organisation

The Symposium was hosted by the Shropshire Geological Society in association with the West Midlands Group of the Geological Society of London.