Indoor Meetings for 2013 - 14

Field Meetings for 2014

Friday: 11 October
How to build a mountain range: the Himalayan orogen Andrew Parsons MSci., University of Leeds

Friday: 15 November
Geology of the Cotswold Water Park with added Mammoths! Neville Hollingworth Ph.D., University of Birmingham

13 December
‘Under the skin of the Lizard’ – a geological walk around the Lizard Peninsula of Cornwall
Lesley Collins, CPGS

10 January
Shale Gas & Shale Oil in the United Kingdom: Status & Forward Prospects Nick Riley MBE Ph.D., Carboniferous Ltd.

14 February
Impacts in the geological past with reference to mass extinctions Paul Kabrna, CPGS

14 March
The development of opencast coal mining in the UK David Blythe Ph.D., University of Newcastle

11 April
Earth, Water, Fire and Air - a bit of the Carboniferous revisited Marion Dunn MSci., University of Durham

Sunday: 4 May
Sykes in Bowland - for Bowland Festival
Paul Kabrna, CPGS

Sunday: 11 May
Arnside
Nick Riley MBE, Ph.D., Carboniferous Ltd.

Sunday: 18 May
Raygill Quarry, Lothersdale and Earl Crag, Cowling - Yorkshire Geology Month
Paul Kabrna, CPGS

Sunday, 25 May
Salthill Quarry Nature Trail - Yorkshire Geology Month
Paul Kabrna, CPGS

June, 27 – 29 (Weekend)
Shropshire (Ludlow, Wenlock Edge, The Long Mynd, and The Wrekin)
Lesley Collins & Paul Kabrna, CPGS

Saturday, 19 July
Craven Inlier at Helwith Bridge, Ribbledale, Yorkshire Dales
Carol Makin, Peter & Linda Lord, CPGS

Sunday, 17 August
Askrigg, the Yorkshire Dales
Lesley Collins, CPGS

Saturday, 6 Sept.
Dinckley Gorge Geotrail, Ribble Valley
Karen Ashworth & Steve Birch, CPGS

 


How to build a mountain range: the Himalayan orogen

Andrew Parsons

Introduction
TBC

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Geology of the Cotswold Water Park with added Mammoths!

Neville Hollingworth

TBC

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‘Under the skin of the Lizard’ – a geological walk around
the Lizard Peninsula of Cornwall

Lesley Collins

TBC

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Shale gas & shale oil in the United Kingdom: Status & Forward Prospects

Nick Riley

TBC

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Impacts in the geological past with reference to mass-extinctions

Paul Kabrna

Introduction
TBC

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The development of opencast coal mining in the UK

David Blythe

TBC

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Earth, Water, Fire and Air - a bit of the Carboniferous revisited

Marion Dunn

TBC

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Field Trips

Sykes in Bowland

Paul Kabrna

Booking essential: contact the AONB office Tel: 01200 448000
or email sandra.silk@lancashire.gov.uk

Time / Date: 10.00 till 15.00, Sunday 4 May

Meeting at: Langden Brook car park at [SD 634 512]

Geological setting:
The high moorland of the Bowland Fells are characterised by tough sandstone outcrops whereas the intervening areas of lower ground, such as the Hodder Valley, are dominated with softer mudstones. The scenery in the Hodder Valley is enhanced by large limestone knolls and abrupt transitions from moorland to wooded valleys, which reflect the local complexity of the geological structure. The limestones and mudstones of the Craven Basin were deposited initially in an open marine environment and were occasionally swept by turbidity currents transporting mainly carbonate sediment. During stable times, sedimentation sometimes caught up with subsidence which resulted in more uniform shallow environments where marine faunas could flourish.

The last (Devensian) glaciation completely buried the landscape in ice, which moved across the district from source areas to the north and north-west, and from the Pennine iceshed to the north-east.

Further Reading
Kabrna, P. (ed.) 2011.  Carboniferous Geology: Bowland Fells to Pendle Hill. Published by Craven & Pendle Geological Society: ISBN: 978-0-9555289-1-0

Riley, N. J. 1990.  Stratigraphy of the Worston Shale Group (Dinantian), Craven Basin, north­west England.  Proceedings of the Yorkshire Geological Society, 48, 163-187.

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Arnside

Nick Riley

Meet at: Arnside Knott Car Park for 11 am at Grid Reference [SD 450 774]

Logistics: Bring packed lunch, binoculars, sunscreen, strong boots and if the weather forecast is for rain - waterproofs. Walking distance about 6 miles, at a leisurely pace. Suitable for families.

Arnside, an Area of Outstanding natural Beauty, is characterised by a landscape of low limestone hills and crags with intervening low-lying mosses and the expanse of Morecambe Bay dominating the western edges. The Limestone geology and coastal aspect of the area sustains a complex mosaic of habitats. There are many semi-natural ancient woodlands, wildflower-rich limestone grasslands, protected limestone pavements, deep peat mosses, coastal salt marshes and estuarine mudflats.

My trip will include the Precambrian life, right through to modern geological processes & ecosystems. A great day out for anyone fascinated by the natural world around them, not just geology, but also natural history.

O.S. Map
1:25000 Explorer Map OL7. The English Lakes South-Eastern area.

Further Reading
Dewey, M. (2008): Limestones of the Arnside area. Walk 9 in Exploring Lakeland Rocks & Landscape (Cumberland Geological Society).

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Raygill Quarry, Lothersdale and Earl Crag, Cowling

Paul Kabrna

Meeting at:  11 am in Raygill Quarry [SD 943 455]: Raygill is located in the village of Lothersdale. It is well signposted from 3 miles away in all directions by brown tourist information signs. Postcode for Satellite Navigation is BD20 8HH. Raygill Fishing Lakes offers year-round trout and coarse fishing, a cafe, and a Wildlife and History Trail for young children run by Amanda Clement (www.raygillfisheries.co.uk).

In the afternoon there will be an option to drive to a car park marked on the O.S. map on Earl Crag [SD 984426] to see the Addingham Edge Grit of Kinderscout age near Cowling. There are two follies, Lunds Tower and Wainman’s Pinnacle on top of the escarpment.

Logistics:  Be prepared for any inclement weather. Hard hat and field boots with ankle support are recommended. Bring a packed lunch or enjoy lunch at the fishing lodge.

Geological setting:  In Raygill during the 1870's whilst quarrying, a pothole was revealed at the south side containing a cache of bones. This find was investigated by the Yorkshire Geological & Polytechnic Society (1880) with the site becoming famously known as the "Raygill Fissure".

The Embsay Limestone which dominates the quarry is a pale coloured turbidite limestone derived from the Askrigg shelf and gravitationally fed into the basin. At the far end of the quarry is the core of the Lothersdale Anticline. There are mineral veins located along faults.  The two most common minerals are calcite and barytes and it is the barytes that was first mined as early as 1876.

O.S. Maps:
Sheet SD 84/94

Further Reading
Kabrna, P. (ed.) 2011.  Carboniferous Geology: Bowland Fells to Pendle Hill. Published by Craven & Pendle Geological Society: ISBN: 978-0-9555289-1-0

Riley, N. J. 1990.  Stratigraphy of the Worston Shale Group (Dinantian), Craven Basin, north­west England.  Proceedings of the Yorkshire Geological Society, 48, 163-187.

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Salthill Quarry Nature Trail

Paul Kabrna

Meeting at:  Salthill Quarry, Nature Trail car park [SD 7550 4265] at 10.30 am. It takes about an hour and a half to complete the trail. There will be a tour in the morning and another in the afternoon at 2pm. In addition for those with botanical interests, the Lancashire Wildlife Trust have also organised a tour of the complex looking at the varied plant species.

Logistics:  Walking is along a relatively well-maintained footpath. As usual be prepared for any inclement weather. However, field boots with ankle support recommended. Bring a packed lunch or visit one of the many local pubs in Clitheroe.

Geological setting:  For much of the Carboniferous Period the Craven Basin recorded relatively deep-water conditions that lay south of the stable, slowly subsiding, shallow-water Askrigg Block. The most celebrated rocks encountered in the Basin are reef mounds or knolls. There are no modern analogues so Salthill Quarry is an ideal locality in which to study these features. Commonly referred to as Waulsortian mounds, they are famous for their echinoderm fauna ably supported by corals, brachiopods, cephalopods, and trilobites.

O.S. Maps:
1:25 000 sheet SD 64 / 74 (Clitheroe and Chipping).
Geol. Survey 1:63 360 Sheet 68 Solid Clitheroe.

Further Reading
Kabrna, P. (ed.) 2011.  Carboniferous Geology: Bowland Fells to Pendle Hill. Published by Craven & Pendle Geological Society: ISBN: 978-0-9555289-1-0

Miller, J. & Grayson, R. F. 1972.  Origin and structure of Lower Viséan "reef limestones near Clitheroe, Lancashire.  Proceedings of the Yorkshire Geological Society, 38, 607-638.

Riley, N. J. 1990.  Stratigraphy of the Worston Shale Group (Dinantian), Craven Basin, north­west England.  Proceedings of the Yorkshire Geological Society, 48, 163-187.

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Geology of Shropshire
(Ludlow, Wenlock Edge, The Long Mynd, and the The Wrekin)

Lesley Collins & Paul Kabrna

Meeting at: 13.30 on Friday afternoon 27 June at Whitcliffe Common car park [506 743]. Walk down the road to the junction with the B4361 (old A49) at Ludford Corner.

Ludford Corner and the Mortimer Forest Trail
The trail is set in the Ludlow Anticline, formed of Wenlock and Ludlow Series of the Silurian and the Downton Series of the Lower Old Red Sandstone, including the famous Ludlow Bone Bed. The Silurian rocks were laid down on an eroded land surface in a shallow marine sea which gradually transgressed from the West, each formation overstepping the next. The oldest rocks in the Silurian sequence, the Llandovery Series, occur further west and are not seen on the trail.

Meeting at: 09.45 on Saturday morning 28 June at the National Trust car park (free) at Presthope, [582 975].

Wenlock Edge
This Edge is a conspicuous and well-known feature in the Shropshire landscape, outcropping NE to SW from Ironbridge to Ludlow. The escarpment is formed by the differential erosion of a succession of gently dipping Silurian limestones and shales forming a classic ‘cuesta’ landscape. The succession starts with the Wenlock Shales forming Ape Dale, overlain by the Much Wenlock Limestone (MWL) which forms the prominent scarp of the Edge. To the south-east the softer Lower Ludlow Shales form Hope Dale with the overlying Aymestry Limestone forming another scarp at View Edge, south-east of Craven Arms.

Meeting at: 14.00 on Saturday afternon 28 June in the National Trust Car Park in Cardingmill Valley [448 944

Cardingmill Valley, The Long Mynd, Church Stretton
The Long Mynd is about 15 km north to south and 7 km east to west. It is an upland plateau, maximum height 516 m, and formed of Precambrian sedimentary rocks. These rocks are all part of the Longmyndian Supergroup which is separated into two units: the Wentnor Group to the west, and the Stretton Group to the east. The Longmyndian Supergroup has been interpreted as an Ediacaran siliciclastic succession, ranging from marine deltaic to alluvial plain or fluvial palaeoenvironments.

Meeting at: 10.00 at Forest Glen car park [639 093] on Sunday moring 29 June. Additional parking is possible 400 m away by the quarry and Shropshire Wildlife Trust Reserve entrance opposite Buckatree Hotel in a roadside lay-by at [641 098].

The Wrekin
In Ercall Quarries Precambrian Uriconian volcanic rocks can be seen intruded by mass of molten rock that cooled to form the Ercall Granophyre. Above this lies the Wrekin Quarztite which is spectacularly exposed at the Ercall Quarry nonconformity. This boundary marks the first appearance of shelly fauna in the fossil record.

O.S. Maps
1: 25 000 Explorer 242 Telford, Ironbridge and The Wrekin.
1: 25 000 Explorer 217 Church Stretton.
O.S. Landranger Series, 1:50 000, Map 137 (Ludlow and Wenlock Edge).
O.S. Explorer Series, 1:25 000, Map 203 (Ludlow).

Geological Maps
1: 25 000 Telford Special Sheet (Solid & Drift).
1: 25 000 Geological Sheet SO 49 (Solid & Drift) Church Stretton.
1: 25 000 Geological Survey Sheet SO 59 (Solid & Drift) Wenlock Edge.

Further Reading
Bassett, M G, 1989. The Wenlock Series in the Wenlock area. 51-73 in “A global standard for the Silurian System”. Holland, C H and Bassett, M G, (editors). National Museum of Wales, Geological series No. 9, Cardiff.

Mcilroy, D. et al. 2005. Fossils and matgrounds from the Neoproterozoic Longmyndian Supergroup, Shropshire, UK. Geol. Mag. 14, pp. 441-455. Cambridge University Press.

Rosenbaum, M. 2007. The Building Stones of Ludlow. Shropshire Geological Society.

Salter, J. W. (1857). On annelide burrows and surface markings from the Cambrian rocks of the Longmynd. Quarterly Journal of the Geological Society, 13, pp. 199-207.

Wenlock Edge Geotrail. Shropshire Geological Society. www.shropshiregeology.org.uk/

Siveter, D. J. et al. 1989. Ludford Lane Corner. British Silurian Stratigraphy, Geological Conservation Review.

The Mortimer Forest Geology Trail 2000. Scenesetters for the Forestry Commission.

Toghill, P 2004. Geology of Britain. ISBN:1 840374047

Toghill, P 2006. Geology of Shropshire. 2nd Edition. The Crowood Press, Marlborough, pp. 256.

Toghill, P and Beale, S. 1994. Ercall quarries, Wrekin area, Shropshire: Geology teaching trail. Geologists’ Association Guide, No. 48. [London: Geologists’ Association].

Wright, A E, Fairchild, I J, Moseley, F and Downie, C. 1993. The Lower Cambrian Wrekin Quartzite and the age of its unconformity on the Ercall Granophyre. Geological Magazine, Vol. 130, pp. 257 - 264.

Wenlock Edge Field Meeting Report (1986). Shropshire Geological Society.

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Craven Inlier at Helwith Bridge, Ribbledale, Yorkshire Dales

Carol Makin, Peter & Linda Lord, CPGS

Meet at: 10.00 am at SD 803 691, the entrance to Dry Rigg Quarry, Helwith Bridge, Nr Settle BD24 0EL

Site 1   Quarry Car Park.  Silurian greywackes and siltstones with graptolites and nodules. Possibility of visiting Quarry education centre subject to availability.

Site 2   Exposed fluted rock via Quarry view point 1 and wildlife area.

Back to cars for Lunch

Site 3   View point 2 and wildlife area.

Site 4   Silurian / Carboniferous unconformity above Foredale.

Site 5   Winskill erratics and the famous “Samsons toe”; also Carboniferous fossils such as brachiopods, fan-shaped corals and crinoids.

Roadside car park at [SD839 665]

If time permits a visit to Victoria Cave can also be made from this car park.

As a bad weather alternative we could visit to the historic Hoffmann Lime Kiln at [SD 824 664].

Introduction:
The Ribblesdale area has a unique character, much of it results from the effects of ice and the way human activities have influenced the land since the ice melted. Millions of years of Earth history have culminated in the landscape, plants, animals, land use and buildings that make the area so attractive.

Geological Setting:
Ancient roots: Nearly half a billion years old, the ancient roots of the Dales are seen in the quarries at Helwith Bridge. These grey slates and sandstones began life as muddy and sandy submarine flows in a deep ocean basin.
For almost 80 million years, they were buried under layers of sediment, uplifted into mountains, squeezed, folded and altered (low grade metamorphism).

Tropical desert: Under arid conditions during the Devonian, weathering and erosion of the rocks took place before they were submerged by the tropical seas of the Carboniferous period.

Tropical seas: The tropical seas deposited horizontal beds of Carboniferous limestone on the eroded, steeply dipping older rocks producing a spectacular unconformity. Shelly limestones packed with fossils prove that around 350 to 335 million years ago the area was a reef-edged lagoon in a tropical sea.

Tropical swamps and deltas: The tropical paradise did not last. By 330 million years ago mud and sand periodically washed into the tropical sea from prograding river deltas. A cyclic repetition of events formed limestones, mudstones, sandstones and coals.

As time progressed, the influence of the river deltas became greater and thick sandstones and mudstones were laid down. The rocks that remain have been faulted, folded and injected with mineral veins. Many deposits have been eroded away, taking with them clues to the events that formed them - nearly 300 million years of rock history are now missing.

Summary of the Stratigraphy

Silurian (Gorstian) strata: The lower beds visible in Dry Rigg Quarry are part of the Horton Formation (Arthurton et al., 1988) being described as a laminated siltstone once known as Horton Flags. There is also a 40 metre member known as the Studfold Sandstone, which lies midway in the succession. This outcrops SE of Studfold itself. The whole formation is circa 700 metres thick. The Horton Formation outcrops in the centre of the Studrigg – Studfold Syncline just south of Combs Quarry. The synclinal axis runs in a sub east-west alignment and the cleavage angle is given as 85º to the north and 80º to the south (BGS 1989). The beds dip at approx 45º south and in the adjacent Dry Rigg Quarry dip in the opposite direction i.e., north. This End Silurian folding occurred as the Iapetus Ocean closed between the so called Laurentian and Baltic continents forming the Caledonian continent circa 395Ma ago.

Visible in the quarry are bentonite layers indicating volcanic ash deposits. This is said to be generally at the base of the Horton Formation.

Lower in the succession is the much thinner Arcow Formation, from 10–35 metres thick, apparently visible in the adjacent Arcow Quarry. This is described as calcareous mudstones, medium-light grey in colour with thin silty laminations.

The Carboniferous (Holkerian age): The bedding above the erosion surface that forms the famous unconformity is of the Kilnsey Formation. Described as well bedded thin and thick beds of medium dark to medium light grey limestones, 56 to 30 m thick.

The above limestone grades from darker into the paler lithologies of the Malham Formation. This transition is identifiable in Foredale Quarry where the unconformity is exposed. The dark limestone (blue stone) is said to be very difficult to process and is said to be the reason for the opening of the upper level in the quarry as this was not as hard  (Johnson 2006). Also noted is the absence of the basal conglomerate below the Kilnsey Formation that is found in some areas e.g. at Austwick Beck Head.

Acknowledgments
Information contained in this document is intended as a field guide for the use of CPGS members during the field trip with no claims to copyright and should not be reproduced without the express permission of the following contributors.

Adrian Kidd, David Johnson & Marion Dunn.
Contributors to the Settle Geology Trails published by North Yorkshire County Council

Alan Harrison BSc  (CPGS) for Geological information

Lafarge Ltd. for Dry Rigg Quarry visitors guide.

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Askrigg, the Yorkshire Dales

Lesley Collins

Meeting at: Askrigg village centre, by the Church.  Free parking in small village car park and by the Church.  Village shop and several cafes, but no Public toilets

Logistics: be prepared for any inclement weather. Field boots with ankle support are recommended. Bring a packed lunch. Walking distance of 1.5 miles for return journey to Askrigg in the morning. After lunch leave Askrigg by the Carperby/Redmire road and drive eastwards to Ballowfield Nature Reserve car parks, [987898].  Meet at footbridge entrance to the Reserve at the first car park. Depending on the weather the afternoon session can be modified to a 2 mile route as opposed to a 4 mile route.

Geological Setting:
The platform carbonate rock-types of the Yoredale Group on the Askrigg Block have been described in detail by Moore (1958). He recognised tweleve types of limestone based on hand-specimen and field characteristics. Moore describe four main types: pure calcite mudstones, crinoidal calcite mudstones, crinoid debris limestones, and crinoid reef limestones. They were deposited during a period of high frequency fluctuating sea level changes. In addition to Carboniferous rocks related to the Yoredale cyclothems, there is also evidence of small mining operations that date as far back as the 17th century (and later . . . ). Apart from Galena (Lead) and Fluorite, Calcite, Sphalerite (Zinc) and Barytes can be found on the remaining spoil heaps.

O.S. Maps:
BGS 1:50 000 Geological Sheet E050 (Hawes. Solid and Drift geology)
BGS 1:50 000 Geological Sheet E040 (Kirkby Stephen. Solid and Drift geology)

Further Reading
Aitkenhead, N. et al., (2002): Pennines and adjacent areas (4th Ed). Published by the British Geological Survey, Nottingham.

Rayner, D.H. and Hemmingway, J.E. (eds). (1974): The Geology and Mineral Resources of Yorkshire Leeds. Poublication of the Yorkshire Geological Society.

Waltham, Tony (2007): The Yorkshire Dales: Landscape and Geology. Published by The Crowood Press Ltd., Ramsbury, Marlborough, Wiltshire SN8 2HR

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Dinckley Gorge Geotrail in the Ribble Valley

Karen Ashworth and Steve Birch, CPGS

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