Stephenson, D., Bevins, R.E., Millward, D., Highton, A.J., Parsons, I., Stone, P. & Wadsworth, W.J. 1999. Caledonian Igneous Rocks of Great Britain. Geological Conservation Review Series No. 17, JNCC, Peterborough, ISBN 1 86107 471 9.
The original source material for these web pages has been made available by the JNCC under the Open Government Licence 3.0. Full details in the JNCC Open Data Policy
Compiled and edited by D. Stephenson British Geological Survey, Edinburgh; R.E. Bevins National Museum of Wales, Cardiff; D. Millward British Geological Survey, Edinburgh; A.J. Highton British Geological Survey, Edinburgh; I. Parsons University of Edinburgh, Edinburgh; P. Stone British Geological Survey, Edinburgh; And W.J. Wadsworth University of Manchester, Manchester
GCR Editor: L.P. Thomas
Joint Nature Conservation Committee
Published by the Joint Nature Conservation Committee, Monkstone House, City Road, Peterborough, PE1 1JY, UK
First edition 1999
© 1999 Joint Nature Conservation Committee
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Contributors
Acknowledgements
Access to the countryside
Foreword P.E. Brown
1 Caledonian igneous rocks of Great Britain: an introduction
Introduction D. Stephenson
Site selection D. Stephenson
Tectonic setting and evolution D. Stephenson
Origin of the late Caledonian magmas D. Stephenson and A.J. Highton
2 Early Ordovician volcanic rocks and associated opholitic assemblages of Scotland
Introduction R Stone and D. Flinn
The Shetland Ophiolite
The Punds to Wick of Hagdale D. Flinn
Skeo Taing to Clugan D. Flinn
Qui Ness to Pund Stacks D. Flinn
Ham Ness D. Flinn
Tressa Ness to Colbinstoft D. Flinn
Virva D. Flinn
The Highland Border Complex
Garron Point to Slug Head C.W. Thomas
Balmaha and Arrochymore Point J.R. Mendum
North Glen Sannox D.J. Fettes
The Ballantrae Complex
Byne Hill P. Stone
Slockenray Coast P. Stone
Knocklaugh P. Stone
Millenderdale P. Stone
Knockormal P. Stone
Games Loup P. Stone
Balcreuchan Port to Port Vad P. Stone
Bennane Lea P. Stone
Southern Uplands
Sgavoch Rock P. Stone
3 Mid-Ordovician intrusions of the North-east Grampian Highlands of Scotland
Introduction W.J. Wadsworth and D. Stephenson
Hill of Barra W.J. Wadsworth
Bin Quarry W.J. Wadsworth
Pitscurry and Legatesden quarries W.J. Wadsworth
Hill of Johnston W.J. Wadsworth
Hill of Creagdearg W.J. Wadsworth
Balmedie Quarry W.J. Wadsworth
Towie Wood W.J. Wadsworth
Craig Hall W.J. Wadsworth
4 Lake District and northern England
Introduction D. Millward
Eycott Hill D. Millward
Falcon Crag B. Beddoe-Stephens
Ray Crag and Crinkle Crags M.J. Branney
Sour Milk Gill M.J. Branney
Rosthwaite Fell M.J. Branney
Langdale Pikes M.J. Branney
Side Pike M.J. Branney
Coniston D. Millward
Pets Quarry M.J. Branney
Stockdale Beck, Longsleddale D. Millward
Bramcrag Quarry S.C. Loughlin
Bowness Knott D.J. Fettes
Beckfoot Quarry B. Young
Waberthwaite Quarry B. Young
Carrock Fell D. Millward
Haweswater D. Millward and B. Beddoe-Stephens
Grainsgill, Caldew Valley S.C. Loughlin
Shap Fell Crags S.C. Loughlin
5 Central England
Introduction D. Millward
Croft Hill J.N. Carney and T.C. Pharaoh
Buddon Hill J.N. Carney and T.C. Pharaoh
Griff Hollow J.N. Carney and T.C. Pharaoh
6 Wales and adjacent areas
Introduction R.E. Bevins
Rhobell Fawr R.E. Bevins
Pen Caer R.E. Bevins
Aber Mawr to Porth Lleuog R.E. Bevins
Castel Coch to Trwyncastell R.E. Bevins
St David's Head R.E. Bevins
Cadair Idris D. G. Woodhall
Pared y Cefn-hir D.G. Woodhall
Carneddau and Llanelwedd D. G. Woodhall
Braich to du M. Smith
Llyn Dulyn M. Smith
Capel Curig M. Smith
Craig y Garn M. Smith
Moel Hebog to Moel yr Ogof M. Smith
Yr Arddu M. Smith
Snowdon Massif M. Smith
Cwm Idwal M. Smith
Curig Hill M. Smith
Sarnau M. Smith
Ffestiniog Granite Quarry M. Smith
Pandy P.J. Brenchley
Trwyn-y-Gorlech to Yr Eifl quarries T.P. Young and W. Gibbons
Penrhyn Bodeilas T.P. Young and W. Gibbons
Moelypenmaen T.P. Young and W Gibbons
Llanbedrog T.P. Young and W Gibbons
Foel Gron T.P. Young and W Gibbons
Nanhoron Quarry T.P. Young and W Gibbons
Mynydd Penarfynydd T.P. Young and W Gibbons
Skomer Island R.E. Bevins
Deer Park R.E. Bevins
7 Late Ordovician to mid-Silurian alkaline intrusions of the North-west Highlands of Scotland
Introduction I. Parsons
Alkaline plutonic complexes
Loch Borralan Intrusion I. Parsons
Loch Ailsh Intrusion I. Parsons
Loch Loyal Syenite Complex I. Parsons
Alkaline minor intrusive rocks
'Grorudite' (peralkaline rhyolite, comendite)
Glen Oykel south L Parsons
Creag na h-Innse Ruaidhe I. Parsons
The Canisp Porphyry (porphyritic quartz-microsyenite)
Beinn Garbh I. Parsons
The Laird's Pool, Lochinver I. Parsons
Cnoc an Leathaid Bhuidhe I. Parsons
'Hornblende porphyrite' (microdiorite, spessaritite)
Cnoc an Droighinn I. Parsons
Luban Croma I. Parsons
Vogesite (hornblende-rich lamprophyre)
Allt nan Uamh I. Parsons
Glen Oykel north I. Parsons
'Nordmarkite' (quartz-microsyenite)
Allt na Cailliche L. Parsons
'Ledmorite' (melanite nepheline-microsyenite)
Camas Eilean Ghlais I. Parsons
an Fharaid Mhór I. Parsons
8 Late Silurian and Devonian granitic intrusions of Scotland
Introduction A.J. Highton
Loch Airighe Bheg N.J. Soper
Glen More W.E. Stephens
Loch Sunart A.J. Highton
Cnoc Mor to Rubh' Ardalanish A.J. Highton
Knockvologan to Eilean a'Chalmain A.J. Highton
Bonawe to Cadderlie Burn A.J. Highton
Cruachan Reservoir A.J. Highton
Red Craig S. Robertson
Forest Lodge D. Stephenson
Funtullich W.E. Stephens
Craig More W.E. Stephens
Garabal Hill to Lochan Strath Dubh-uisge W.E. Stephens
Loch Dee W.E. Stephens
Clatteringshaws Dam Quarry W.E. Stephens
Lea Larks W.E. Stephens
Lotus Quarries to Drungans Burn W.E. Stephens
Millour and Airdrie Hill WE. Stephens
Ardsheal Hill and Peninsula I.M. Platten
Kentallen I.M. Platten
9 Late Silurian and Devonian volcanic rocks of Scotland
Introduction D. Stephenson
South Kerrera G. Durant
Ben Nevis and Allt a'Mhuilinn D.W. McGarvie
The Glencoe Volcano — an introduction to the GCR sites
D. W McGarvie
Bidean nam Bian D.W. McGarvie
Stob Dearg and Cam Ghleann D.W. McGarvie
Buachaille Etive Beag D.W. McGarvie
Stob Mhic Mhartuin D.W. McGarvie
Loch Achtriochtan D.W. McGarvie
Crawton Bay R.A. Smith
Scurdie Ness to Usan Harbour R.A. Smith
Black Rock to East Comb R.A. Smith
Balmerino to Wormit M.A.E. Browne
Sheriffmuir Road to Menstrie Burn M.A.E. Browne
Craig Rossie M.A.E. Browne
Tillicoultry M.A.E. Browne
Port Schuchan to Dunure Castle G. Durant
Culzean Harbour G. Durant
Turnberry Lighthouse to Port Murray G. Durant
Pettico Wick to St Abb's Harbour D. Stephenson
Shoulder O'Craig P. Stone
Eshaness Coast D. Stephenson
Ness of Clousta to the Brigs D. Stephenson
Point of Ayre N.W.A. Odling
Too of the Head N.W.A. Odling
References
Glossary
Index
Brett Beddoe-Stephens British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Richard E. Bevins Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF1 3NP.
Michael J. Branney Department of Geology, University of Leicester, University Road, Leicester LEI 7RH.
Patrick J. Brenchley Department of Earth Sciences, University of Liverpool, The Jane Herdman Laboratories, Brownlow Street, Liverpool L69 3BX.
Michael A.E. Browne British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
John N. Carney British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG.
Graham Durant Hunterian Museum, University of Glasgow, University Avenue, Glasgow G12 8QQ.
Douglas J. Fettes British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Derek Flinn Department of Earth Sciences, University of Liverpool, The Jane Herdman Laboratories, Brownlow Street, Liverpool L69 3BX.
Wes Gibbons Department of Earth Sciences, University College of Wales, Cardiff, PO Box 914, Cardiff CFI 3YE.
Andrew J. Highton British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Susan C. Loughlin British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Dave McGarvie The Open University, 2 Trevelyan Square, Boar Lane, Leeds LS1 6ED. John R. Mendum British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
David Millward British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Nicholas W.A. Odling Department of Geology and Geophysics, University of Edinburgh, The Grant Institute, West Mains Road, Edinburgh EH9 3JW.
Ian Parsons Department of Geology and Geophysics, University of Edinburgh, The Grant Institute, West Mains Road, Edinburgh EH9 3JW.
Timothy C. Pharaoh British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG
Ian Al. Platten School of Earth and Environmental Science, University of Greenwich, Medway Campus, Pembroke, Chatham Maritime, Kent ME4 4AW.
Steven Robertson British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Martin Smith British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Richard A. Smith British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
N. Jack Soper Gams Bank, Riverside, Threshfield, North Yorkshire BD23 4NP.
W. Edryd Stephens School of Geography and Geosciences, University of St Andrews, Purdie Building, North Haugh, St Andrews, Fife KY16 9ST.
David Stephenson British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Philip Stone British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Christopher W. Thomas British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
W. John Wadsworth Department of Geology, University of Manchester, Manchester M13 9PL.
Derek G. Woodhall British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Brian Young British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA.
Timothy P. Young Department of Earth Sciences, University College of Wales Cardiff, PO Box 914, Cardiff CF1 3YE.
This volume is the combined work of the 31 authors listed on pages xi–xii, most of whom, in addition to their own site descriptions, have made valuable comments on other aspects of the work. Individual chapters have been compiled by the authors of the relevant chapter introductions and have been edited by R.E. Bevins (Chapter 6), A.J. Highton (Chapter 8), D. Millward (chapters 1, 4, 5 and 9), D. Stephenson (chapters 3, 7, 8 and 9) and P. Stone (Chapter 2). Overall compilation and editing is by D. Stephenson. The GCR editor, L.P. Thomas provided guidance throughout the writing and compilation and the referee's comments of P.E. Brown were particularly welcome during the final stages of editing. The project has been managed by N.V. Ellis, N.K. Cousins and A.J. Carter for JNCC and D.I.J. Mallick and D.J. Fettes for BGS.
The initial site selection and site documentation for this volume was by R.E. Bevins, I.W. Croudace, B.P. Kokelaar, M.J. LeBas, D.T. Moffat, D. O'Halloran, I. Parsons, J.L. Roberts, W.E. Stephens, R.G. Thomas and W.J. Wadsworth. Since this initial exercise, much new mapping and refined interpretation has taken place, particularly in the Lake District and North Wales, and some revision of the original GCR site list has been necessary. M.J. Branney, M.F. Howells and B.P. Kokelaar have provided much helpful advice on this revision and the necessary amendments to the GCR documentation have been greatly facilitated by S. Campbell (for CCW), T. Moat (for EN) and R. Threadgould (for SNH).
Additional information and advice were provided by T.R. Astin (Shetland and Orkney sites), D. Gould (NE Grampian Highlands intrusions) and J.E.A. Marshall (Siluro-Devonian biostratigraphy). Diagrams were drafted by S.C. White and C.F. Pamplin (Xipress IT Solutions, Newmarket); photographs were scanned and prepared by T. Bain (BGS, Edinburgh). Photographs from the BGS collection are reproduced by kind permission of the Director, BGS ©NERC; all rights reserved (PR/23–27). The references were compiled by M.W. Kinnear, and the index was prepared by B.J. Amos.
Finally, on behalf of all of the site authors, we would like to record our thanks to the owners and managers of land and quarries who have allowed access to the sites, either during previous work or specifically for the GCR exercise.
This volume is not intended for use as a field guide. The description or mention of any site should not be taken as an indication that access to a site is open or that a right of way exists. Most sites described are in private ownership, and their inclusion herein is solely for the purpose of justifying their conservation. Their description or appearance on a map in this work should in no way be construed as an invitation to visit. Prior consent for visits should always be obtained from the landowner and/or occupier.
Information on conservation matters, including site ownership, relating to Sites of Special Scientific Interest (SSSIs) or National Nature Reserves (NNRs) in particular counties or districts may be obtained from the relevant country conservation agency headquarters listed below:
Countryside Council for Wales, Plas Penrhos, Ffordd Penrhos, Bangor, Gwynedd LL57 2LQ.
English Nature, Northminster House, Peterborough PE1 1UA.
Scottish Natural Heritage, 12 Hope Terrace, Edinburgh EH9 2AS.
Britain is exceptional in the continuity of geological history and variety of geological phenomena that are preserved within a comparatively small area. Since the early days of the geological sciences, the area has continued to provide outstanding contributions, theoretical and practical, to the understanding of Earth processes. No section of this long and distinguished history of scientific investigation is more noteworthy than that arising from the outstanding variety and preservation of the Caledonian igneous rocks. This volume describes localities that are regarded as representative of the long and complex evolution of the Caledonian igneous activity. Many of the sites listed have played a key role in interpretations marking major advances in geological thinking. One needs only to recall Hutton's deductions on the origin of granite from observations made in Glen Tilt over two hundred years ago, or the modern realization of the tectonic significance of Caledonian ophiolites. There are many problems remaining and new interpretations to be made, and the descriptions of key localities in this volume will, as well as the basic objective of conservation, provide both a tool and a stimulus for further research.
With regard to further research, one of the features that emerges from a review of the Caledonian igneous rocks and which is brought out in the introduction to the volume, is the breadth of interest these rocks have for different branches of the Earth sciences, including the petrologist looking for plate-tectonic models in explanation of the variety and spatial distribution of the igneous rocks, the structural geologist looking to the igneous rocks for support of his thoughts on ancient plate movements and the isotope geochemist endeavouring to provide a tinie framework for both. To all those interested in the comprehensive review presented, this GCR volume is potentially of great value in providing, as it does, summary access to both the detail and the broader picture of Caledonian igneous activity.
Accurate description and recording of field data is a fundamental aim of the Geological Conservation Review. Interpretations of the observations may vary over time but the role of the field geologist in providing the key data is paramount. In this review of the Caledonian igneous rocks the importance of detailed field observations is particularly well illustrated by the elegant modern interpretations of volcanological phenomena described at GCR sites in the Lake District and Glen Coe. These are outstanding examples of major advances resulting essentially from 'map and observation geology' (hammers nowadays tend to be rather frowned on, particularly at conservation sites). Detailed laboratory examination without adequate field support is always likely to lose much of its value, or at the worst the interpretations will be incorrect. The GCR review of the Caledonian igneous rocks is a welcome re-affirmation of the fundamental importance of field work.
The rocks described occur in Scotland, England and Wales and the variety and importance of the sites covered inevitably have made this a lengthy compilation. Individual site descriptions from thirty one contributors are organized into nine chapters under seven compilers. In most cases the sites have been described by acknowledged 'experts', many of whom have known and worked on the sites for many years. Some have been described by persons with no previous knowledge of the site, but with a background in related igneous rocks, and almost all have been visited by their author. The few exceptions that have not been visited had recent authorative descriptions that could be summarized. Dr D. Stephenson and his team of co-authors are to be congratulated on the clarity achieved and also in preserving the individuality of presentation of the site descriptions whilst ensuring conformity with the overall aims and standard format of the Geological Conservation Review. The resulting volume will be valuable to both the amateur and professional for many years to come.
P.E. Brown FRSE Professor Emeritus University of St Andrews