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Geology of the Appleby district — a brief explanation of the geological map Sheet 30 Appleby

D Millward, M McCormac, R A Hughes, D C Entwisle, A Butcher, and M G Raines

Bibliographic reference: Millward, D, McCormac, M, Hughes, R A, Entwisle, D C, Butcher, A, and Raines, M G. 2003. Geology of the Appleby district — a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 30 Appleby (England and Wales).

Keyworth, Nottingham: British Geological Survey, 2003. © NERC 2003 All rights reserved.

Copyright in materials derived from the British Geological Survey's work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining NERC permission. Contact the BGS Intellectual Property Rights Manager, British Geological Survey, Keyworth. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract.

The grid, where it is used on figures, is the National Grid taken from Ordnance Survey mapping. © Crown copyright reserved Ordnance Survey licence number GD272191/2003.

(Front cover) The southern part of the Haweswater Reservoir and Harter Fell viewed from Mardale Banks [NY 480 125]. The reservoir occupies a major glacial trough cut into rocks of the Borrowdale Volcanic Group (Photograph D Millward).

(Rear cover)

(Geological succession) Summary of the geological succession in the Appleby district.

Notes

The word 'district' refers to the area of the geological 1:50 000 Series Sheet 30 Appleby. National grid references are given in square brackets and all lie within 100 km square NY. Symbols in round brackets after lithostratigraphical names are the same as those used on the geological map.

Acknowledgements

This Sheet Explanation was compiled mainly from BGS reports listed in the Information sources (p.28). M McCormac was responsible for the sections on Carboniferous rocks and Quaternary deposits, R A Hughes that on the Permian and Triassic rocks, M Raines concealed geology, A Butcher water resources, and D Entwisle foundation conditions; the remaining sections were compiled by D Millward. The Sheet Explanation was reviewed by B Young and D E Highley, and edited by A A Jackson. Figures are drawn by R J Demaine, P Lappage and G Tuggey. The farmers and landowners are thanked for their co-operation and assistance during the resurvey of the district.

Geology of the Appleby district (summary from rear cover)

(Rear cover)

(Geological succession) Summary of the geological succession in the Appleby district.

The Appleby district extends from the north-eastern part of the Lake District National Park, across the Vale of Eden to the Pennine escarpment. Farming, tourism and limestone and gypsum/anhydrite, extraction dominate the local economy. Major communication links through the area have existed since Roman times, with High Street forming the route from west Cumbria to Carlisle and in more recent times, the Vale of Eden providing ready motorway connection between northern and southern Britain. Ullswater, Haweswater and the Wet Sleddale reservoir provide important water resources for the Manchester conurbation.

Lower Palaeozoic igneous and sedimentary rocks in the Lake District and Cross Fell are overlain in the Vale of Eden by Carboniferous, Permian and Triassic sedimentary rocks. New work on the 450 million year old Borrowdale Volcanic Group in the Lake District greatly extends our knowledge and understanding of the nature of the volcanism, depositional processes and environment operating during this very short but explosive episode of our history. During early Carboniferous times, between 360 and 330 million years ago, the district lay at the junction between the Lake District Block and the Stainmore Trough to the south-east and stratigraphical links are established between their successions. New information on the 260 to 240 million year old Permian and Triassic rocks provide important information on the gypsum and anhydrite resources.

The effects of the Quaternary glaciation are displayed in the present-day landscape of the glacially sculpted valleys between rugged mountains of the Lakeland fells and the widespread cover of glacial deposits, most of which accumulated within the last 30 000 years. Ecologically important areas of limestone pavement occur along the Carboniferous escarpment.

The new geological maps ('Solid', and 'Solid and Drift') and this Sheet Explanation provide valuable information on a wide range of earth science issues. These include traditional aspects such as sedimentation, volcanism, structure, metamorphism and mineralisation, but also cover applied aspects such as mineral, energy and water resources, waste disposal, foundation conditions and conservation.

Chapter 1 Introduction

This Sheet Explanation summarises the geology of the district covered by the geological 1:50 000 Series Sheet 30, Appleby, published in Solid, and Solid and Drift editions in 2003. Further details of the geology are to be found in the various Technical and Research reports listed in the Information Sources section.

This rural area of Cumbria includes parts of the Lake District, Vale of Eden, and the lower parts of the Pennine escarpment (Plate 1). The glacially sculpted valleys in the west of the district lie within the Lake District National Park. There, Ullswater and Haweswater, along with the smaller Wet Sleddale reservoir, provide important water resources for the Manchester conurbation. The main towns are Penrith, just to the north of the district and Appleby in the east. The M6 motorway crosses the centre of the district, and is a major transport route linking the north and south of Britain. The local economy is dominated by farming, though tourism is particularly important in the upland areas. Significant resources of limestone and gypsum/anhydrite are currently exploited.

Lower Palaeozoic igneous and sedimentary rocks crop out in the Lake District and Pennine escarpment; fault-bound blocks within the latter comprise the Cross Fell inlier. By contrast, Carboniferous, Permian and Triassic sedimentary rocks form the bedrock to the Vale of Eden. Quaternary deposits are widespread, particularly in the Vale of Eden.

Sedimentary rocks of the Ordovician Skiddaw Group were deposited some 460 Ma ago as siliciclastic turbidites in deep water on the northern margin of Gondwana prior to, or during, separation of the microcontinent of Eastern Avalonia. Less than 10 Ma later, these strata were uplifted and, in response to subduction of Iapetus oceanic crust beneath Avalonia, large volumes of calc-alkaline intermediate and silicic lavas and pyroclastic rocks were erupted. Remnants of the subaerial volcanoes now comprise the Borrowdale Volcanic Group (Plate 2). The Lake District granitic batholith was intruded during this episode which lasted less than 5 million years. After the magmatism ceased, thermal subsidence was followed by development of a foreland basin during the final stages of closure of the Iapetus Ocean. During these events immense volumes of sand, silt and mud turbidites were deposited to form the Windermere Supergroup.

The Lower Palaeozoic rocks were folded, faulted and cleaved during the Acadian Orogeny, about 400 Ma ago. The Shap and Weardale granites were emplaced towards the end of this episode. These and the earlier granites of the Lake District form the cores of the Lake District and Alston blocks which exerted a profound control on sedimentation in the area for many millions of years subsequently. Desert environments persisted during Mid and Late Devonian times, and widespread extensional basins became filled with alluvial-fan and braided river channel deposits. The remnants of these systems are contained in the Upper Old Red Sandstone rocks of the district.

During early Carboniferous times, about 360 Ma ago, the district lay at the margin of a shallow marine embayment on the north-west flank of the Stainmore Trough, between the emergent Lake District and Alston blocks that had been underpinned by the Early Palaeozoic granites. Coastal plain, peritidal and lagoonal bioclastic carbonate rocks dominate the sedimentary record of this period, but in late Arundian times a fluviodeltaic system spread across the district from the north-east. Repeated marine transgressions established shallow, inshore, marine ramp environments in the southern part of the district, extending progressively northwards to inundate all but the centre of the Lake District Block in Holkerian to Asbian times. The carbonate ramp evolved into a platform with water depths of generally less than 20 m during Asbian times. Extensive areas emerged during low-stands, and fluviodeltaic sediments were deposited upon some of the karstic surfaces. This pattern of sedimentation presaged the onset of 'Yoredale' cyclothems which became established at the end of Asbian times and persisted through to the early Namurian, when deltaic conditions dominated.

From Namurian to mid-Westphalian times, supply of river-borne terrestrial sediment from the north and east balanced local subsidence sufficiently to maintain a freshwater deltaic environment with only brief marine incursions. Sedimentation was terminated at the end of Carboniferous times by Hercynian deformation and uplift.

In Early Permian times, extensional faulting along the Pennine and Dent fault systems led to the formation of the Vale of Eden basin and to the accumulation of aeolian and fluvial deposits of the Appleby Group. Regional subsidence in Late Permian times resulted in dominantly lacustrine and continental sabkha environments and evaporite deposition within the Cumbrian Coast Group. Fluvial sedimentation and deposition of the Sherwood Sandstone Group dominated in early Triassic times. The Vale of Eden basin lay at the margin of an area of subsidence that extended into the Solway, west Cumbria, and the eastern Irish Sea.

The major unconformity between the Triassic strata and the Quaternary deposits represents a period of about 240 million years for which no deposits are preserved. Regionally, Late Permian thermal subsidence eventually led to marine conditions being established widely in northern England by Early Jurassic times, but the area became emergent once again from Mid Jurassic to Early Cretaceous times. Opening of the North Atlantic Ocean by Mid-Cretaceous times led to widespread shelf conditions with deposition of the Chalk across the area, and by the end of the Cretaceous the area attained its maximum Mesozoic burial. Erosion that followed emergence at the end of the Cretaceous, removed all strata of Jurassic and later age from the district.

During the Quaternary, successive glaciations produced the impressive landforms that characterise the Lake District. Most of the glacigenic deposits are those left by the Dimlington Stadial glaciation (about 26 000 to 13 000 years ago) during the late Devensian. This reached its maximum about 22 000 years ago and deglaciation started about 18 000 years ago. Small glaciers returned briefly to the heads of some of the valleys in the upland areas in the south-west of the district during the Loch Lomond Stadial (11 000 to 10 000 years ago) before renewed amelioration of the climate brought about their retreat at the onset of the Holocene.

Survey history

The Appleby district was surveyed originally on a scale of six inches to one mile, and published as Quarter Sheet 102 SW (one inch to one mile), with an accompanying memoir (Dakyns et al., 1897). The volcanic rocks around Ullswater and Haweswater were described by Moseley (1960, 1964) and Nutt (1970) respectively. The Carboniferous rocks of the south-east of the district were described by Rowley (1969). The Quaternary landforms of the Lower Palaeozoic inlier in the district were described by Mitchell (1931) and those of the Vale of Eden by Hollingworth (1931). This Sheet Explanation is based on the latest survey, from 1995 until 2000. Details are included in the Information sources section.

Geological description

Concealed geology

The colour-shaded relief maps of the regional Bouguer gravity and aeromagnetic data of the district (Figure 1) are based on the data used by Lee (1989) to interpret the form of the Lake District batholith. The Bouguer gravity anomaly map shows three main features: an anomaly high in the north-west over the Ullswater Inlier associated with dense Skiddaw Group and basic igneous rocks in the lower part of the Borrowdale Volcanic Group, a gravity low in the central and southern parts related to the low-density Haweswater and Shap granites, and a progressive decrease in gravity values towards the north-east reflecting the thickening low-density Carboniferous and Permo-Triassic sedimentary sequence beneath the Vale of Eden.

The prominent aeromagnetic anomaly high in the north-west of the district corresponds to magnetic Eycott Volcanic Group rocks at shallow depth beneath Carboniferous rocks. A strong, dipolar magnetic anomaly near the southern margin coincides with the Shap Pluton. Lee (1989) interpreted this as the combined effects of a moderately magnetic granite and highly magnetic contact-metamorphosed volcanic rocks. The low magnetic values over the concealed Haweswater Granite indicate that it is nonmagnetic, suggesting that it is separate from, and unrelated to, the Shap Pluton.

There are several east-north-east-trending geophysical lineaments, the most prominent of which are the Crummock and Ullswater lineaments. These may reflect deep-seated and long-lived fracture zones that were re-activated to influence structural development of the Lower Palaeozoic rocks and intrusion of the Lake District batholith (Lee, 1989).

Ordovician and Silurian

Skiddaw Group (SkG) rocks occur in the Ullswater, Bampton and Cross Fell inliers (Figure 2). These strata comprise mudstone, siltstone and some sandstone of Arenig to early Llanvirn age. The Tarn Moor Formation (TMF) is the principal unit in the Ullswater and Bampton inliers and its correlative in the Cross Fell inlier is the Kirkland Formation (KdF). Their bases are not seen in the district. Graptolite faunas recovered from the few exposures of both units are indicative mostly of the Didymograptus artus Biozone (D. bifidus of Burgess and Holliday, 1979; Skevington, 1970), though younger strata of D. murchisoni Biozone age were identified from the Tarn Moor Tunnel linking Ullswater to Haweswater (Wadge et al., 1972). On Tailbert Bank [NY 528 144], the Tailbert Formation (Tbt) is fault-bound, but small exposures elsewhere suggest that these rocks overlie the Tarn Moor Formation unconformably. The age of the Tailbert Formation has not been proved.

The Borrowdale Volcanic Group (BVG) crops out from Ullswater to Shap in the south-west of the district, and in the Cross Fell Inlier. Basaltic, andesitic and dacitic lavas, sills and volcaniclastic rocks comprise a succession, probably more than 6000 m thick, that was erupted in subaerial and shallow subaqueous environments during Caradoc times. In the district, the unconformity at the base of the group is exposed only in Keld Gill [NY 5396 1341], where near-horizontal volcanic rocks overlie weathered, near-vertically dipping Skiddaw Group mudstones.

The basal unit of the group, the Birker Fell Formation (BFA) (Figure 3), thins eastwards from 2750 m on Beda Fell [NY 424 164], to about 980 m in Swindale [NY 530 138]. Pyroclastic units at the base of the formation include the Little Meldrum Member (LMel), containing abundant Skiddaw Group mudstone clasts, and the Lanty Crag Member (Lty) which incorporates the Bampton Conglomerate of Nutt (1970). These members represent the remnants of initial phreatomagmatic eruptions. Andesite and basaltic andesite lavas, typically 30 to 65 m thick, make up most of the formation, whereas dacite lavas south-east of Ullswater and in Gowbarrow Park are up to 220 m thick. Petterson et al. (1992) interpreted the lava sequence, which occurs throughout the Lake District, as having formed from coalesced low-profile volcanoes. On Low Birk Fell [NY 410 190] and Hallin Fell, the eroded succession of lavas displays a fine example of 'trap' topography. The Tarn Moor Tunnel [NY 4766 2270] to [NY 4949 2069] provided an important section through the lower part of the formation in otherwise poorly exposed ground (Wadge et al., 1972). A few intercalations of volcaniclastic rocks, from a few metres to about 175 m thick, occur locally throughout the formation. The Frith Crag Member (FrCr) lies approximately 600 m above the base of the formation.

The Scalehow Formation (Scw) marks a major change to explosive volcanism, represented by emplacement of welded ignimbrite sheets to form the Whelter Knotts (Wlt), Froswick (Fsw) and Lincomb Tarns (LTa) formations (Figure 4), (Figure 5). These are intercalated with a wide range of dominantly volcaniclastic sedimentary lithofacies within the Mardale (Mrl), Seathwaite (Set), Esk Pike (EsP) and Deepdale (Dpd) formations. Short-lived periods of andesite and dacite lava effusion are represented in the upper part of the group by the Brock Crags Formation (BkCg) and Middle Dodd Dacite (MdD) respectively. The 1200 m-thick andesite succession of the Wet Sleddale Formation (WetS)is also thought to comprise a stack of lavas, though contemporaneous sills may also be present.

The stratified welded silicic ignimbrite succession of the Whelter Knotts Formation (Wlt) (Figure 4); (Plate 3) is considered to have been erupted during caldera formation centred around Haweswater. Phreatomagmatic fall-out and surge deposits at the base of the formation testify to the ingress of large volumes of surface water into the volcano. Some of these rocks in the Powley's Hill Member (PlH) are unusually rich in garnet. At Kidsty Pike [NY 4472 1260], a striking, 6 m-thick nodular tuff lies 30 to 40 m above the base of the formation. The andesitic to dacitic Froswick Formation (Fsw) extends westwards from the district to Ambleside. It is succeeded by the Woundale Formation (Wou), the remains of a phreatomagmatic tuff-ring or cone. The Lincomb Tarns Formation (LTa) is the most widespread silicic ignimbrite in the Lake District.

Less intense explosive volcanism continued during accumulation of the intervening clastic sedimentary units and is represented by thin intercalations of pyroclastic rocks, but many of them are too thin and limited in extent to be mapped separately. Among the more significant are the Cawdale (Cawd), Brown Howe (BnH) and Rowantreethwaite (Rwt) members which occur near the base of the Mardale Formation (Mrl) (Figure 4). Bedded accretionary lapilli-tuff, up to about 4 m thick, and tentatively correlated with the Glaramara Tuff of the adjacent Ambleside and Keswick districts (Millward et al., 2000), occurs about 150 m below the top of the Seathwaite Fell Formation. At least 30 m above the tuff, and between 90 and about 130 m below the top of the formation lies the St Raven's Edge Member (SRE) (Figure 5).

In the Cross Fell Inlier, the Borrowdale Volcanic Group consists of approximately 1100 m of volcaniclastic rocks, including the Knock Pike Formation (KnPk), a major silicic ignimbrite (Figure 6). The succession there cannot be correlated with that in the Lake District. Marine sedimentary rocks of the succeeding Windermere Supergroup (Win) occur in the Cross Fell Inlier (Figure 6). These are seen best in Swindale Beck [NY 684 271] to [NY 690 280] which is the type-section for the Dufton Formation (DnSh), one of the most important developments of upper Caradoc rocks in Britain. The Hirnantian strata exposed in the beck were included previously in the Swindale Shales (Burgess and Holliday, 1979), but the lithofacies and faunal assemblage are comparable to the Ashgill Formation (Ahl) of the Lake District, to which they have been assigned subsequently (Kneller et al., 1994).

Devonian

Devonian, 'Old Red Sandstone'-type rocks are preserved within fault-bounded troughs and comprise the Mell Fell Conglomerate Formation (MFC), and the Blind Beck Sandstone Member (BBkS) of the Shap Wells Conglomerate Formation (Figure 7). The polygenetic red-bed conglomerates contain clasts derived mainly from the Borrowdale Volcanic Group and Windermere Supergroup. No fossils diagnostic of the age of these rocks are present, but a Mid to Late Devonian age is inferred because probable Tournaisian dolerite intrusions cut the Mell Fell Conglomerate (Macdonald and Walker, 1985).

Carboniferous

Dinantian and Namurian sedimentary rocks crop out across the central part of the district in a north-west-trending belt. Dinantian rocks overstep Devonian strata south-east of Mell Fell to rest unconformably on Lower Palaeozoic rocks. The Carboniferous succession, approximately 800 m thick, is divided into three groups (Figure 7). The basal Ravenstonedale Group (RVS), comprising fluvial sandstones and shallow marine carbonates, is overlain successively by carbonate shelf and ramp deposits of the Great Scar Limestone Group (GSCL), and by marine and fluviodeltaic deposits of the Yoredale Group (YORE).

South of the Kirk Rigg Fault, the Ravenstonedale Group consists of four formations, but to the north only one, the Marsett Formation, is present. The group thins from 200 m near Shap to 50 m west of Penrith, representing northward onlap from the Stainmore Trough, which lay to the south. The intercalated conglomerate, sandstone and mudstone forming the Marsett Formation (MaSa) were deposited as marine conditions first became established in the district. Mudstone beds at the top of the formation grade upwards into the Stone Gill Limestone Formation (STE). Palynomorphs present in rocks equivalent to these two formations in the Ravenstonedale area are Courceyan to Chadian in age (Holliday et al., 1979). The Shap Village Limestone Formation (SHVI) is equivalent to the Shap Limestone of Dakyns et al. (1897). The common presence of the coral Dorlodotia pseudovermiculare is probably indicative of a Chadian age. The uppermost unit of the group, the Ashfell Sandstone Formation (AFL), forms a prominent bench feature punctuated by many disused shallow workings for sandstone. Interbedded thin calcareous units contain a coral-brachiopod fauna that indicates a late Arundian age for these strata (Garwood, 1913).

The Great Scar Limestone Group comprises about 160 m of limestone and is divided into eight formations. The Scandal Beck, Brownber, Breakyneck Scar and Potts Beck limestone formations are part of the Stainmore Trough succession, and in the Appleby district they crop out only along the southern margin of the district where the first three of these formations interdigitate with the uppermost units of the Ravenstonedale Group. The Ashfell and Knipe Scar limestone formations span the entire district.

The Scandal Beck Limestone Formation (SCBL) forms the basal unit of the Great Scar Limestone Group south-east of the Anne's Well Fault. Mudstone and algal dolostone, at the base of the formation (Coldbeck Limestone Member), are overlain by oolite and pebbly wavy bedded limestone and dolostone with siltstone interbeds. Oolite and pebbly calcarenite form the succeeding Brownber Formation (BNBF). The overlying Breakyneck Scar Limestone Formation (Bre) contains an early Arundian fauna.

The Ashfell Limestone Formation (AFL) forms the basal unit of the group throughout most of the district (Plate 4). The formation thins progressively northwards and is absent on Askham Fell [NY 491 225] (Garwood, 1913). North of the Kirk Rigg Fault the equivalent rocks constitute the Seventh Limestone Formation (LM7) of west Cumbria nomenclature (Arthurton and Wadge, 1981). The distinctive flaggy and commonly cross-bedded, sandy limestone contains an abundant coral, brachiopod and gastropod fauna, including Lithostrotion vorticale and Davidsonina carbonaria. The top of the formation is marked by the presence of beds variously containing dark grey, cross-bedded crinoidal grainstone, grey mudstone with bivalves and vuggy porcellanous limestone (the Bryozoa band of Garwood, 1913).

The Asbian Potts Beck Limestone Formation (PBL) is up to 45 m thick in the southern part of the district, but thins out just north of Shap village. The well jointed limestone, commonly with mottled calcrete textures ('pseudobreccias'), forms grassy escarpments at Hardendale [NY 5810 1380] and Long Scar Pike [NY 5940 1090]. Typically, its coral-brachiopod fauna includes Siphonodendron junceum, Palaeosmilia murchisoni and Dibunophyllum.

The Knipe Scar Limestone Formation (KNL), and the overlying Robinson Limestone (RnL) and Birkdale Limestone (BKL) formations where present, typically form parallel escarpments and extensive limestone pavements. The formation is 70 m thick in the south, thinning to half that on Askham Fell [NY 491 225]. Sporadic thin interbeds of fluviodeltaic mudstone, siltstone and sandstone thicken markedly to the north of the Kirk Rigg Fault. There, they divide the succession into discrete limestone units, which are named individually (Arthurton and Wadge, 1981), and collectively comprise the Eskett Limestone Formation (ESKT).

Limestones in the Knipe Scar and Eskett limestone formations have a depositional cyclicity similar to that seen in the southern Lake District and north Lancashire (Horbury, 1989). Cycle boundaries are marked by palaeokarst surfaces and stratiform, mottled calcrete textures, and are commonly overlain by bentonitic clay palaeosols derived from volcanic ash fall-out. Fossil faunas, though sparsely represented, include species of Siphonodendron, Lithostrotion and Hexaphyllia coral colonies, Gigantoproductus brachiopod shells and stromatolites, which may indicate an Asbian age.

The Yoredale Group comprises up to 500 m of cyclical marine and fluviodeltaic beds of Brigantian and early Namurian age. The constituent Alston and Stainmore formations reflect the marked decrease in limestone units at the outset of Namurian sedimentation. Where these rocks are seen beneath the unconformity at the base of the Permian strata, they are typically red-brown, pink or violet in colour.

The Alston Formation (AG) typically represents repeated cycles of marine to fluviodeltaic sedimentation. Each major cycle begins with a limestone, rarely more than 10 m thick, succeeded by bedded units of terriginous mudstone and sandstone. The eleven limestone units recognised in the district give rise to extensive escarpments in the higher, drift-free areas. The common occurrence of Actinocyathus floriformis and of the Girvanella nodular band of Garwood (1913) in the Askham Limestone Member (ASKL) indicate that the base of the formation closely coincides with that of the Brigantian stage. The Great Limestone Member (GL), at the top of the formation, is taken to be Pendleian in age.

The lowest limestones in the succession are wackestones containing Siphonodendron sp. biostromes and algal bands, apparently indicating low-energy conditions. Current-deposited packstone and grainstone, commonly crowded with crinoid debris, dominate limestones higher in the succession. Glauconite, rarely seen in Carboniferous rocks, occurs in the Three Yard Limestone Member (TYL) (Rowley, 1969). Dolomitisation is common only in the Single Post Limestone Member (SPL), which is a vuggy dolostone.

The thickness of clastic rocks within each cyclothem remains fairly constant, but the proportion of sandstone and mudstone is very variable. Marine mudstone units occur at some intervals, grading laterally into thin limestones such as the Cockle Shell and Halligill Limestone (Hgl) members (Rowley, 1969). Seatearths are present at the top and within some cycles, and a workable coal seam, the Reagill Coal, is present within the district.

Stainmore Formation (SMGP) rocks underlie a wide, linear tract of drift-covered ground south of Penrith, and occur in faulted inliers within the Permian cover south of Appleby. This formation comprises a cyclical succession of terriginous mudstone and sandstone with up to four beds of limestone in the lower part. These were deposited in a delta system, and the large-scale cross-bedding in the sandstones indicates a northerly source for the sediment. An early Namurian age, probably Pendleian to Arnsbergian, has been determined for similar strata in the Barrock Park Borehole, in the adjacent Penrith district (Arthurton and Wadge, 1981).

Permian and Triassic

A thick layer of glacial deposits conceals most of the Permian and Triassic rocks in the district and the sequence is best known from cored boreholes in the adjacent Penrith and Brough districts (Arthurton and Wadge, 1981; Burgess and Holliday, 1979). The lithostratigraphy used here (Figure 8), follows the scheme of Barnes et al. (1994).

These rocks have yielded few biostratigraphically useful fossils, but the Eden Shales Formation is partly Late Permian in age, ranging from at least EZ1 to EZ3 (Burgess and Holliday, 1979). In view of this, it is likely that the underlying Penrith Sandstone Formation is early Permian in age, and that the overlying St Bees Sandstone Formation is early Triassic. However, the precise position of the base of the Triassic System in the Vale of Eden is unknown, and its placement at the base of the St Bees Sandstone Formation is arbitrary.

The Appleby Group (Apy) comprises the Penrith Sandstone Formation and the brockram breccia facies. The basal beds overlap the underlying Carboniferous strata which range from the Stainmore Formation in the north-west of the district to the middle of the Alston Formation south of Appleby. The Penrith Sandstone Formation (PS) is best exposed in the west where, partly because the sandstones are more indurated by secondary silica cementation, they form weak scarp features. Silicification is most common in the middle and upper parts of the formation. Waugh (1970) has proposed that silica dust, produced by abrasion in the arid environment, was dissolved and circulated in alkaline groundwaters, resulting in the deposition of silica during sedimentation. 'Brockram' (Bk) is a local term for laterally impersistent units of a polygenetic breccia facies present at the base of, and within, the Lower Permian sandstones of Cumbria. The word is believed to have originated locally as a description for 'broken rock'. Because of its occurrence at several stratigraphical horizons, brockram is regarded as a facies, and not a formal lithostratigraphical unit.

The Eden Shales Formation (EdSh) of the Cumbrian Coast Group (CCo) comprises a succession of mudstone and sandstone with four evaporite beds (A–D beds), and a marine unit, the Belah Dolomite (Figure 9). The use of the evaporite units to divide the formation was first established by Sherlock and Hollingworth (1938) and adopted by most later authors. An important environmental change occurred after deposition of the D bed, which led to the accumulation of aeolian silt and sand on an emergent land surface. These beds are succeeded upwards by sandstones of increasingly fluvial character, culminating in the almost exclusively fluvial facies of the St Bees Sandstone Formation (SBS) that spread over much of Cumbria at this time. The base of this formation is gradational and is taken at the base of the first thick-bedded fluvial sandstone within the thin-interbedded sandstone and siltstone of the Eden Shales Formation.

Intrusive rocks

Most of the intrusive rocks in the district (Figure 10) were emplaced during Caradoc volcanism. Contemporaneous andesite sills comprise a significant proportion of the Borrowdale Volcanic Group. Where they have been emplaced within sedimentary formations, they typically have margins of peperitic breccia, formed as the magma came into contact with wet, unconsolidated or poorly consolidated volcaniclastic sediment. By contrast, andesite sills within the Esk Pike Formation between Caudale Moor [NY 413 101] and Raven Crag [NY 419 111] have thin, chilled margins, indicating intrusion into consolidated rock, possibly at a very late stage of the volcanism. The concealed Haweswater Granite and many of the dykes in the district are also believed to belong to this episode.

The Haweswater intrusions (Haweswater complex of Nutt, 1979) comprise plugs and dyke-like mafic masses that crop out over an area of about 19 km2 around the northern part of Haweswater. An Ordovician age is indicated by the regional association with the volcanic rocks, similarity in alteration style and geochemistry, and by the presence of a weak cleavage locally. Gravity data preclude a link at depth to a large mafic intrusion.

The renowned Shap Pluton, a granite containing large orthoclase-perthite phenocrysts, crops out south of Wet Sleddale. It was emplaced during the Early Devonian Acadian deformation episode and has been the subject of much research interest (Stephenson et al., 1999 and references therein). The microgranite dykes are part of a widespread swarm associated with the pluton.

Basic dykes and a volcanic neck, filled with lapilli-tuff, which cut the Mell Fell Conglomerate on Little Mell Fell [NY 430 240], are inferred to have been emplaced during an episode of early Carboniferous volcanism during the initial rifting of the Solway– Northumberland trough (Macdonald and Walker, 1985).

Structure

Synsedimentary and volcanotectonic deformation affected many parts of the Borrowdale Volcanic Group. Thickness and facies changes across, for example, the Bannerdale and Martindale faults cutting the Whelter Knotts Formation result from volcanotectonic activity. Broader scale extensional faults, such as the Brant Street and Mullender faults, are believed to have controlled aggradation of the volcanic succession (Millward, 2002).

During the Acadian tectonic event in Early Devonian times, earlier formed structures in the Lower Palaeozoic rocks were tightened and a regional, north-east- to east-north-east-trending cleavage was imposed, in response to north-west to south-east crustal shortening. At this time, north-east-trending faults in the Wet Sleddale area probably developed through dislocation of the common limbs of upright folds, similar to those in the Coniston area associated with the Westmorland monocline (Millward et al., 2000). The Swindale Fault Zone is a multi-stranded fracture system with high internal strain, and is interpreted as a shear zone with a component of sinistral displacement. Major north–south fractures such as the Troutbeck Fault Zone are parallel to the Lake District Boundary Fault in west Cumbria, and the Coniston and Pennine faults, which are probably re-activated major basement fractures.

The extent of post-Acadian deformation within the Lower Palaeozoic rocks is difficult to assess, though a number of major faults cutting these rocks can be traced into overlying strata. Most of these displacements have been attributed to end-Carboniferous re-activation of existing structures during the Hercynian Orogeny. Extensional re-activation of the Causey Pike, Rosgill Moor and Anne's Well faults probably resulted in the creation of fault-bound troughs in which Devonian sediments accumulated.

Though there is no evidence within the district for direct fault control on subsequent Dinantian sedimentary processes, changes in stratigraphical thickness, facies and formation limits appear to coincide with the trace of faults orientated north–south and north-east–south-west to east–west. The Anne's Well Fault is an example of the first of these sets. North–south topographical lineaments within the Dinantian outcrop are highlighted by the modern drainage system and may be the trace of faults, but generally this cannot be proved. For example, the northward course of the Lowther valley lies along the northward projection of the Rosgill Moor Fault.

Faults orientated east–west to north-east–south-west predominantly affect the lower part of the Dinantian succession. Marked steps or swings in the limestone escarpment have resulted from displacements on these faults. Also, the Kirk Rigg Fault marks the northward limit of Chadian and Arundian strata in the area.

Above the Great Scar Limestone Group, few faults or folds disturb the lateral continuity of the Upper Palaeozoic outcrops. By contrast, strike parallel, north-westerly trending faults, such as the Yanwath Fault, have significant displacements. The Eden Shales Formation is cut by many north to north-north-westerly faults. These structures are associated with the multi-stranded, and still geoseismically active, Pennine Fault Zone, which has a complex history involving Acadian, Hercynian and, possibly, Alpine movements (Arthurton and Wadge, 1981).

Metamorphism

Skiddaw Group rocks have been subjected to deep diagenesis and low-anchizonal grades of regional metamorphism (Fortey, 1989). In the Borrowdale Volcanic Group, regional metamorphism produced the assemblage carbonate and white mica, with chlorite, quartz, epidote, leucoxene/titanite and opaque oxide; white mica, in particular, is associated with cleavage fabrics. There is little evidence in the volcanic rocks, of earlier phases of hydrothermal and low-grade burial metamorphism that have been recognised in the western Lake District (Millward et al., 2000).

South of Wet Sleddale, the volcanic rocks have a brownish hue, reflecting progressive recrystallisation to quartz-biotite-hornfels within the contact metamorphic aureole of the Shap Pluton. Cordierite, or amphibole and pyroxene occur in some of the rocks. Biotite overgrows the cleavage, indicating that emplacement of the granite postdated cleavage formation (Boulter and Soper, 1973). However, microgranite dykes associated with the granite have weakly cleaved margins, suggesting that the granite was emplaced during periods of stress relaxation within the Acadian deformation event (Soper and Kneller, 1990).

Mineralisation

Compared with other areas of the Lake District, there are relatively few occurrences of mineralisation within the Lower Palaeozoic rocks of the Appleby district (Figure 11). Small examples of copper mineralisation north of Brother's Water and at Haweswater have parageneses similar to veins at Coniston (Millward et al., 2000). Extensive hydrothermal mineralisation is associated with the Shap Pluton and its thermal aureole. Veins containing a garnet-epidote-hornblende assemblage are characteristic of the aureole and are well seen in Shap Blue Quarry [NY 563 105] (Firman, 1957). The lead-zinc mineralisation associated with the Troutbeck and other faults near Hartsop is part of the suite of veins that was worked at Greenside Mine in Patterdale and considered to have an early Carboniferous age (Stanley and Vaughan, 1982).

Quaternary

The earliest glacigenic deposits, comprising gravelly diamicton, stratified sand and gravel, and laminated silt and clay, occur in the Eamont valley around Penruddock, near Appleby and in boreholes west of Penrith (Dakyns et al., 1897; Arthurton and Wadge, 1981). These deposits have not been dated, but all were deformed by, and hence predate, the main Devensian regional ice sheet. They may be interpreted as ice-margin, outwash and glaciolacustrine deposits associated with an early advance/retreat cycle (or cycles) of Lake District glaciation.

Much of the Vale of Eden and the flanks of the Pennine escarpment, up to about 350 m above sea level, is mantled by a lodgement till, the Penrith Till Formation (Thomas, 1999), laid down by the regionally extensive ice sheet during the Dimlington Stadial. The till is generally 2 to 5 m thick, but up to 20 m where it is characteristically moulded into low-amplitude drumlins. The till is a diamicton, variable in colour and texture, and includes beds and lenses of gravel, sand and deformed, laminated clay. Across the Permo-Triassic outcrop, the till has a sandy matrix and is pale brown to red-brown. South-west of this, to the Lakeland fell-margin, the till contains pebble to cobble-sized clasts in a clay/silty clay matrix and is typically grey to red-brown. The clasts are dominantly locally derived limestone and sandstone, along with some Lower Palaeozoic lithologies. Trains of erratic blocks of Shap granite are common in the south of the district, particularly in the Lowther valley, where some large individual boulders, such as the Galloway Stone [NY 587 099], bear individual names.

Within the Lakeland fells, till mainly covers the lower valley slopes of Ullswater, Patterdale, Boredale, Haweswater, Swindale and Wet Sleddale. It is a coarse diamicton of locally derived rock debris, containing sporadic bodies of poorly sorted sand and gravel. Drumlins are common. At higher elevations, hummocky moraines and boulder-strewn till ridges occupy high-level corries and nivation hollows at the head of north- and east-facing valleys around the High Street fells and in Swindale (Sissons, 1980; Wilson and Clark, 1998). These deposits were formed by small valley glaciers during the Loch Lomond Stadial, and have created distinctive moraine-dammed tarns such as Blea Water [NY 447 107].

At maximum glaciation, ice flow within the Lakeland fells of the district was towards the north-east and east; on the flanks of the fells, ice flow was northwards from the area of the Shap granite, and within the Eden valley north-westwards (Boardman, 1991). In the last area, the drumlins are orientated parallel to the strike of the underlying solid formations, which may also form cores to the drumlins. However, in the north-east, the basal part of the till contains boulders of granite derived from the Southern Uplands of Scotland, testifying to an early stage of southward ice-flow (Clark, 1990).

Meltwater drainage was effected through numerous channels on the flanks of the Lakeland fells and Pennine escarpment. A prominent, anastomosing system of dry channels can be traced from the fells west of Askham [NY 516 241] extending to, and across, the Lowther–Eamont watershed. Drainage across the lower ground of the Eden valley was through an impeded network of low-gradient, inter-drumlin channels, in places containing temporary postglacial lakes. Mounded glaciofluvial sand and gravel deposits have a limited distribution in the district, but small kames and eskers are associated with meltwater channels in the area west of Penrith and on the slopes of Knock Pike [NY 685 282]. Shallow late-glacial lakes, such as those that existed in the Lowther valley, beside Bampton [NY 520 180], and Ormside [NY 700 170] were infilled with alluvium and by the build-up of alluvial fans at watercourse tributary intersections (Burgess and Holliday, 1979).

Periglacial conditions prior to the last climatic amelioration led to the accumulation of scree aprons below crags in many of the valleys in the Lakeland fells. Solifluction deposits and landslips also occurred on over-steepened till slopes.

The landscape changed rapidly in immediate postglacial times. Peat accumulated to a depth of several metres on the gently rolling high fells, notably west of Shap. The retreat of ice from the district left wide areas of glacially scoured limestone pavement exposed along the crest of the Carboniferous escarpment. The most extensive, and ecologically important, pavements are found at Great Asby Scar [NY 650 100] and Crosby Ravensworth Fell [NY 605 100].

The major rivers of the district now follow water-courses largely inherited from glacial times. A former channel of the River Eden, blocked with till, has been proved from boreholes north of Appleby. The rivers Eamont, Lowther and Eden flow within a broad meander belt flanked by a succession of wide, low-angle alluvial terraces of sand and gravel (Plate 5). The alluvium of these terraced flood-plains is silt and fine sand, though the modern watercourse is commonly floored with bedrock.

Chapter 3 Applied geology

The principal land use in this rural district is farming. Tourism is important in the local economy. The western part of the district lies within the Lake District National Park and the Cross Fell area lies within the North Pennines Area of Outstanding Natural Beauty. There is a long history of mining and quarrying in the Vale of Eden.

Mineral resources

This section has been summarised largely from Young et al. (2001). Compared with other parts of the Lake District the extraction of metalliferous minerals was not significant in the district. Myers Head Mine, at Low Hartsop, dates from the late 19th century, but very little galena is thought to have been raised (Figure 11).

By contrast, there is a long history of gypsum and anhydrite mining in the district (Tyler, 2000). However, in recent years, the demand for mineral gypsum for plasterboard manufacture has declined due to the availability of desulphuogypsum derived from removing sulphur dioxide from the flue-gases at coal-fired power stations, and today only the Newbiggin [NY 626 280] and Birkshead [NY 668 260] mines remain active. The A bed is mined for gypsum at Birkshead, while B bed anhydrite is mined at Newbiggin. There are no modern descriptions of the active mines, but Sherlock and Hollingworth (1938) published accounts of the Stamp Hill and Acorn Bank mines, and of the Thistle Plaster Quarry and Mine on the site of the present-day Birkshead Mine.

Limestone is the principal source of crushed rock aggregate in Cumbria. Most of the commercial quarrying in the district is from the upper part of the Great Scar Limestone Group and currently, there is no active exploitation of beds below the Ashfell Limestone. The most consistently pure limestone is the Knipe Scar Limestone Formation, and this is quarried at Shap Beck [NY 547 185] and Hardendale [NY 585 140], the latter producing lime for the steel industry. Most of the Knipe Scar Limestone and the underlying Potts Beck Limestone are valued for their high purity (> 97% CaCO₃). Limestone from the lower part of the Yoredale Group was formerly extracted around Penrith.

The volcanic rocks are an important resource of crushed rock aggregate. Some of the coarser welded tuffs produce high specification aggregates with very high polished stone values and such a product was obtained formerly from Knock Pike Quarry [NY 687 285]. Hornfelsed andesite within the aureole to the Shap granite is worked at the Shap Blue Quarry [NY 564 106] to produce an aggregate suitable for road surfacing materials, concrete products and railway track ballast. It has high relative density (2.83) and a particularly high abrasion resistance (AAV 1.4). Shap granite was formerly worked for roadstone and as a crushed rock aggregate.

Sand and gravel resources within the district include glaciofluvial and river deposits, confined mainly to the major river valleys. Current working in the district is only from the Knock Parish Quarry [NY 685 288].

Many local rock types are used locally as sources of building stone. In the National Park most of the buildings are of volcanic rocks. Shap granite has been quarried commercially for at least the last 150 years from Shap Pink Quarry, just to the south of the district, and quantities are still produced intermittently for decorative work. There is some small-scale quarrying of the Scandal Beck Limestone for building stone around Orton, also just south of the district. The Penrith and St Bees sandstones were traditionally valued as a source of building stone and small amounts are still produced today for this purpose, though there are no currently worked sites in the district. Where silicified, the former is hard, coherent, and splits readily along foreset surfaces to provide an excellent building and paving stone.

Energy resources

The variable thickness of blanket peat spread across parts of the Lakeland fells has not been exploited for fuel or horticultural use.

The granitic batholith underlying the Lake District has been investigated as a potential hot dry rock geothermal resource because of its size and possible above-average content of the radioactive elements uranium, thorium and potassium (Lee, 1986). Measurements in boreholes sunk into the Shap granite showed heat-flow values significantly above the UK average. This granite has limited extent, and it is not thought that the values obtained for this intrusion are representative of the composite batholith as a whole.

Water resources

Rainfall in the district varies from an annual average of 2800 mm around Haweswater to 850 mm in the Vale of Eden. The average evapotranspiration rate is 475 mm/yr. There is abundant surface water in the form of lakes and rivers, the latter dominated by the catchment of the River Eden and its tributaries, the rivers Lowther and Eamont. The annual infiltration rate into the western part of the district is estimated at less than 40 mm, but this increases to between 115 and 530 mm into the more permeable Permo-Triassic rocks.

The National Water Well Archive includes over 30 spring supplies in use, 11 shallow wells and over 50 boreholes for the district. The boreholes are generally concentrated in areas underlain by Permo-Triassic rocks. There are many other springs present in the district that may or may not be exploited. Licensed water abstractions in the district total approximately 1300 Ml/d of which 94 per cent is from reservoirs, 5 per cent from rivers and 1 per cent from boreholes.

The Lower Palaeozoic rocks have low permeability and intergranular porosity and are not significant aquifers, but small private supplies of water from springs have a low total dissolved solids content. Within the Carboniferous rocks, the limestones and sandstones bear water whereas the intervening mudstones act as confining beds. The limestones typically have low matrix porosity and permeability, and become aquifers only where a network of solution-enhanced fractures is present. Karstic conditions may be developed locally, and groundwater levels and yields from boreholes in these fractured systems are commonly variable and difficult to predict.

The Penrith and St Bees sandstone formations are major aquifers, yielding water through intergranular and fracture flow. The latter formation generally yields less than the former and is not greatly exploited in the district. Abstraction from the Penrith Sandstone at Cliburn [NY 588 245] is used for public supply. Yields from boreholes intercepting the more silicified parts of the Penrith Sandstone are lower than average, but less indurated parts of the formation pose problems for borehole construction. Groundwater quality is generally good with a total dissolved solids content of about 150 mg/l.

The Eden Shales Formation generally acts as a confining bed between the underlying and overlying sandstones. Gypsum and anhydrite in the formation increases the sulphate content of an otherwise good quality groundwater in adjacent strata. Several large, licensed groundwater abstractions are recorded around Kirkby Thore, where boreholes have been sunk to dewater the formation for gypsum and anhydrite mining.

The variable thickness and characteristics of the till throughout the district significantly restricts recharge into parts of the underlying aquifers (Younger and Milne, 1997). Groundwater is present in superficial deposits within the glaciated valleys, in river gravels and other granular material. Sand and gravel lenses in hillside till, and peat is another potential source of groundwater from springs. Water quality from these sources will be similar but more mineralised than that of associated surface waters.

Haweswater and Wet Sleddale reservoirs provide water for the Manchester conurbation. The former was created from two small pre-existing lakes, the levels of which were raised by the construction of a 505 m wide, 47 m high, hollow concrete buttress gravity dam. The reservoir is 6.4 km long and holds 84 000 million litres when full. Since 1971, water has also been pumped from Ullswater along an aqueduct from Heltondale.

Foundation conditions

Most of the available geotechnical data from the district are for Quaternary deposits investigated for the construction of major roads, such as the M6. Information about the solid formations is restricted to borehole logs proving rock head, specific investigations for pipelines, and for the area surrounding the Haweswater dam.

The Skiddaw Group mudstones weather readily to form a weak material consisting of slab- and prism-shaped fragments. Weathering of these rocks may result in slope instability and maintenance problems, particularly in cuttings. The strength of the igneous rocks is reduced particularly near to the surface by the presence of open or clay-lined joints and small-scale mineral veins. Fracture zones associated with faults are of variable width and may contain very poor quality rock.

The Carboniferous limestones are generally strong to very strong. Near the surface, clay-filled joints are common and sporadic fractures may be filled with hematite or carbonate. Engineering problems associated with karst in the Carboniferous limestones include dolines, undulating rock head, clay-filled joints, voids and caverns, and variable foundation conditions. Though cavities may be expected anywhere in the limestone succession their distribution and size is not known.

Karst-like dissolution features in the evaporite beds of the Eden Shales Formation were noted at the abandoned McGhie's Quarry [NY 642 268] and Acorn Bank Mine [NY 618 278] by Sherlock and Hollingworth (1938) and Dakyns et al. (1897) (Plate 6). Also, Ryder and Cooper (1993) described a phreatic cave system with chambers up to 6 m across, in gypsum deposits then being extracted from the B bed at Houtsay Quarry, Newbiggin [NY 624 276]. The cave system has since been destroyed by mining. Though not extensive, these raise the possibility that other concealed cave systems, and the potential hazards they present to surface stability, are present within the district.

Subsidence features in pasture land near Acorn Bank Cottages [NY 6192 2780] consist of steep-sided pits, some 5 m deep and up to 15 m across. It is not known whether these are natural subsidence hollows related to gypsum dissolution or are related to collapse of underground workings at the now abandoned Acorn Bank Mine. Other areas of surface subsidence occur near Stamp Hill Mine for example [NY 666 253]. The collapse of underground workings is known to be associated with gypsum and anhydrite mining. However, most have not been formally documented and the extent to which underground collapses have caused subsidence at the surface is incompletely known. The undulating topography of the drift-covered surface makes the recognition and delineation of subsidence hollows difficult.

The Penrith Sandstone is commonly weathered to depths of up to 6 m below the surface. The degree of weathering decreases with depth from a residual soil to a slightly jointed moderately weak to moderately strong sandstone. The soil comprises dense (but in places loose) sand, clayey or silty fine- to medium-grained sand with some fine to coarse sandstone gravel.

Till throughout the district generally provides good foundation conditions, but the weathered uppermost 0.5 to 2.0 m may be soft. Problems may be encountered in construction with resilience during compaction and susceptibility to behaviour change with small alterations in moisture content. However, lithological variation in the glacial deposits may lead to unpredictable groundwater conditions. The clays are typically of low plasticity and, therefore, likely to cause few shrink/swell problems. The sulphate content is low and the pH is generally slightly acidic to slightly alkaline (pH 6.3 to 7.4).

Slope stability problems are generally restricted to river banks in till, activated partly by the erosion of the rivers. One landslide has been mapped affecting the Kirkland and Knock Pike formations on the eastern flank of Knock Pike [NY 688 283].

Seismicity

Minor seismic events arising from natural earthquakes are not uncommon in north-west England (Musson, 1994). Notable earthquakes originating in the region that have been felt within the district are those at Whitehaven in 1786, around Carlisle in 1901, 1915, 1979 and 1980, in Wensleydale in 1933, near Kirkby Stephen in 1970, and near Ambleside in 1988. The epicentre of the earthquake that occurred on 17 March 1871 and felt over a very wide area is believed to have been between Appleby and Alston. Though there are no grounds for regarding the Appleby district as especially prone to seismic activity, the recorded events indicate that, along with much of Britain, earthquakes of unusual intensity possibly could occur.

Conservation and geological heritage

Localities in the district have been recognised, by English Nature, as being of national importance in terms of their geological heritage. These have received designations as Sites of Special Scientific Interest (SSSI), and thus have been afforded some protection from development or damage. Regionally Important Geological/Geomorphological Sites (RIGS) are recognised for their value primarily for teaching purposes. There are 13 SSSI and 16 RIGS in the Appleby district. The ecologically important limestone pavement on Great Asby Scar is one of three National Nature Reserves in the district (Plate 1).

Information sources

Further geological information held by BGS relevant to the Appleby district is listed below. This includes published maps, memoirs and reports, along with open-file maps and reports. Other sources include borehole records, mine plans, fossils, rock samples, thin sections, hydrogeological data and photographs. Enquiries concerning geological data for the district should be addressed to the National Geoscience Information Service, BGS, Edinburgh.

BGS catalogue of geological maps and books is available on request, and gives a full list of the geochemistry, geophysics, hydrogeology and mineral maps that are currently available. Other data may be accessed on the BGS web site including a Lexicon of named rock units, information on borehole records and core, and data on other BGS collections, including access to the photographic collection (addresses on the back cover). Further information relevant to the Appleby district is listed below.

Maps

Geological maps

1:10 000 and 1:10 560

The maps at 1:10 000 scale covering all or part of 1:50 000 geological Sheet 30 Appleby are listed below (p.28), along with the surveyors' initials and dates of survey. The surveyors were: B Beddoe-Stephens, A M Bell, I C Burgess, R A Hughes, S C Loughlin, M McCormac, D Millward, J Pattison, P Stone, A J Wadge and D G Woodhall. The maps are not published, but are available for public consultation in the BGS libraries in Edinburgh and Keyworth, and the London Information Office, Natural History Museum, South Kensington. Uncoloured copies are available for purchase from BGS sales desks. The earlier maps are available for public reference at the BGS Library, Edinburgh.

List of 1:10 000 scale maps

Digital geological map data

Many BGS maps are available in digital form, which allows the geological information to be used in GIS applications. These data must be licensed for use. Details are available from the Intellectual Property Rights Manager at BGS Keyworth. The current availability of these can be checked on the BGS web site at: http://www.bgs.ac.uk/products/digitalmaps/digmapgb.html

Geochemical atlas

The Lake District, 1992

The Geochemical Baseline Survey of the Environment (G-Base) is based on the collection of stream sediment and stream water samples. The geochemical atlas is also available in digital form (on CD-ROM or floppy disk) under licensing agreement. BGS offers a client-based service for interactive GIS interrogation of G-Base data.

Geophysical maps

Colour shaded relief gravity and Bouguer anomaly maps are available at various scales (1:1 500 000; 1:625 000; 1:250 000).

Books and reports

The various memoirs books, reports and papers relevant to the Appleby district are listed in the reference section. More details of the geology can be found in the BGS Technical and Research reports covering the geology of combined 1:10 000 scale geological sheets. BGS Technical and Research reports may be purchased from BGS or consulted at the BGS and other libraries. There is a collection of internal BGS Biostratigraphical Reports which are also available.

Popular publications consist of a 1:200 000 scale full colour satellite image poster for the Lake District and surrounding area, a Holiday geology map guide (Lake District) published in 1997, and a Holiday geology guide (The Lake District Story) published in 1999.

Documentary collections

Collections of records of borehole and site investigations relevant to the district, are available for consultation at the BGS, Edinburgh. The collection consists of the sites and logs of about 1350 boreholes. BGS maintains a mining and quarrying dataset and hosts the National Water Well Archive.

Material collections

The BGS photographs can be viewed on the web site and in BGS libraries; the more recent photographs are also held in the BGS Information Office in London. Copies of the photographs can be purchased from the Photographic Department, BGS, Edinburgh.

There are petrological and palaeontological collections for the district. The former contains more than 700 rock specimens and thin sections, most of which are from the volcanic and intrusive rocks. The palaeontological samples are held by the BGS at Keyworth.

References

Most of the references listed below are held in the Libraries of the British Geological Survey at Keyworth (Nottingham) and Edinburgh. Copies of the references can be purchased subject to the current copyright conditions. BGS library catalogue can be searched on line at: geolib.bgs.ac.uk

Arthurton, R S, and Wadge, A J. 1981. Geology of the country around Penrith. Memoir of the Geological Survey of Great Britain, Sheets 24 (England and Wales).

Barnes, R P, Ambrose, K, Holliday, D W, and Jones, N S. 1994. Lithostratigraphical subdivision of the Triassic Sherwood Sandstone Group in west Cumbria. Proceedings of the Yorkshire Geological Society, Vol. 50, 51–60.

Boardman, J. 1991. Glacial deposits in the English Lake District. 175–183 in Glacial deposits of Great Britain and Ireland. Ehlers, J, Gibbard, P L, and Rose, J (editors). (Rotterdam: Balkema.)

Boulter, C A, and Soper, N J. 1973. Structural relationships of the Shap granite. Proceedings of the Yorkshire Geological Society, Vol. 39, 365–369.

Burgess, I C, and Holliday, D W. 1979. Geology of the country around Brough-under Stainmore. Memoir of the British Geological Survey, Sheet 31 (England and Wales).

Clark, R. 1990. The last glaciation of Cumbria. Proceedings of the Cumberland Geological Society, Vol. 5, 187–208.

Cooper, A H, Rushton, A W A, Molyneux, S G, Hughes, R A, Moore, R M, and Webb, B C. 1995. The stratigraphy, correlation, provenance and palaeogeography of the Skiddaw Group (Ordovician) in the English Lake District. Geological Magazine, Vol. 132, 185–211.

Dakyns, J R, Tiddeman, R H, and Goodchild J G. 1897. The geology of the country between Appleby, Ullswater and Haweswater. Memoir of the Geological Survey of Great Britain (Quarter Sheet 102 SW).

Firman, R J. 1957. Fissure metasomatism in volcanic rocks adjacent to the Shap granite, Westmorland. Quarterly Journal of the Geological Society of London, Vol. 113, 205–222.

Fortey, N J. 1989. Low grade metamorphism in the Lower Ordovician Skiddaw Group of the Lake District, England. Proceedings of the Yorkshire Geological Society, Vol. 47, 325–337.

Garwood, E J. 1913. The Lower Carboniferous succession in the north-west of England. Journal of the Geological Society of London, Vol. 68, 449–586.

Holliday, D W, Neves, R, and Owens, B. 1979. Stratigraphy and palynology of early Dinantian (Carboniferous) strata in shallow boreholes near Ravenstonedale, Cumbria. Proceedings of the Yorkshire Geological Society, Vol. 42, 343–356.

Hollingworth, S E. 1931. The glaciation of western Edenside and adjoining areas and the drumlins of Edenside and the Solway Basin. Quarterly Journal of the Geological Society of London, Vol. 87, 281–359.

Horbury, A D. 1989. The relative roles of tectonism and eustacy in the deposition of the Urswick Limestone in south Cumbria and north Lancashire. 153–169 in The role of tectonics in Devonian and Carboniferous sedimentation in the British Isles. Arthurton, R S, Gutteridge, P, and Nolan, S C (editors). Occasional Publication of the Yorkshire Geological Society, No. 6.

Kneller, B C, Scott, R W, Soper, N J, Johnson, E W, and Allen, P M. 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219–240.

Lee, M K. 1986. Hot Dry Rock. 21–42 in Geothermal Energy: the potential in the United Kingdom. Downing, R A, and Gray, D A (editors). (London: HMSO for the British Geological Survey.)

Lee, M K. 1989. Upper crustal structure of the Lake District from modelling and image processing of potential field data. British Geological Survey Technical Report, WK/89/1.

Macdonald, R, and Walker, B H. 1985. Geochemistry and tectonic significance of the Lower Carboniferous Cockermouth lavas, Cumbria. Proceedings of the Yorkshire Geological Society, Vol. 45, 141–146.

Millward, D. 2002. Early Palaeozoic magmatism in the English Lake District. Proceedings of the Yorkshire Geological Society, Vol. 54, 93–121.

Millward, D, and 22 others. 2000. Geology of the Ambleside district. Memoir of the British Geological Survey, Sheet 38 (England and Wales).

Mitchell, G H. 1931. The geomorphology of the eastern part of the Lake District. Proceedings of the Liverpool Geological Society, Vol. 15, 322–338.

Moseley, F. 1960. The succession and structure of the Borrowdale volcanic rocks south-east of Ullswater. Quarterly Journal of the Geological Society of London, Vol. 116, 55–84.

Moseley, F. 1964. The succession and structure of the Borrowdale volcanic rocks northwest of Ullswater. Geological Journal, Vol. 4, 127–142.

Musson, R M W. 1994. A catalogue of British earthquakes. British Geological Survey Technical Report, WL/94/04.

Nutt, M J C. 1970. The Borrowdale Volcanic Series and associated rocks around Haweswater, Westmorland. Unpublished PhD thesis, University of London (Queen Mary College).

Nutt, M J C. 1979. The Haweswater complex. 727–733 in The Caledonides of the British Isles — reviewed. Harris, A L, Holland, C H, and Leake, B E (editors). Geological Society of London Special Publication No. 8.

Petterson, M G, Beddoe-Stephens, B, Millward, D, and Johnson, E W. 1992. A pre-caldera plateau-andesite field in the Borrowdale Volcanic Group of the English Lake District. Journal of the Geological Society of London, Vol. 149, 889–906.

Rowley, C R. 1969. The stratigraphy of the Carboniferous Middle Limestone Group of West Edenside, Westmorland. Proceedings of the Yorkshire Geological Society, Vol. 37, 329–350.

Ryder, P, and Cooper, A H. 1993. A cave system in Permian gypsum at Houtsay Quarry, Newbiggin, Cumbria, England. Cave Science, Vol. 20, 23–28.

Sherlock, R L, and Hollingworth, S E. 1938. Gypsum and anhydrite; Celestine and Strontianite. Memoir of the Geological Survey of Great Britain.

Sissons, J B. 1980. The Loch Lomond advance in the Lake District, northern England. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 71, 13–27.

Skevington, D. 1970. A lower Llanvirn graptolite fauna from the Skiddaw Slates, Westmorland. Proceedings of the Yorkshire Geological Society, Vol. 37, 395–444.

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Figures and plates

Figures

(Figure 1a) Bouguer gravity anomalies. Colour shaded-relief image illuminated from the north with contours at 1 milligal (mGal) intervals. Anomalies calculated against the Geodetic Reference System 1967 using a variable Bouguer reduction density and referred to the National Gravity Reference Net 1973. Geophysical lineaments after Lee (1989).

(Figure 1b) Total magnetic field. Colour shaded-relief image illuminated from the north with contours at 10 nanotesla (nT) intervals. Anomalies referred to a variant of IGRF90. Geophysical lineaments after Lee (1989).

(Figure 2) Lithostratigraphy and biostratigraphy of the Skiddaw Group (from Cooper et al., 1995).

(Figure 3) Details of the Birker Fell Formation.

(Figure 4) Details of the Scalehow, Whelter Knotts and Mardale formations.

(Figure 5) Details of the higher formations of the Borrowdale Volcanic Group in the district.

(Figure 6) Details of the Borrowdale Volcanic Group and Windermere Supergroup lithostratigraphy in the Cross Fell inlier (after Burgess and Holliday, 1979).

(Figure 7) Devonian and Carboniferous rocks of the Appleby district.

(Figure 8) Details of the Permian and Triassic rocks of the district.

(Figure 9) A generalised vertical section through the Eden Shales Formation.

(Figure 11) Mineralisation and summary of mining history in the Appleby district.

Plates

(Plate 1) View looking north-east from Great Asby Scar [NY 648 092] across the Vale of Eden to the Pennine escarpment. The limestone pavement is developed on the Knipe Scar Limestone Formation (L2983).

(Plate 2) Subaerial erosion surface in tuffs at the top of the Birker Fell Formation (Borrowdale Volcanic Group), east of the summit of Kidsty Pike [NY 4478 1254] (Photograph D Millward).

(Plate 3) Eutaxitic lapilli-tuff (ignimbrite) in the lower part of the Whelter Knotts Formation east of the summit of Kidsty Pike [NY 4475 1257] (Photograph D Millward).

(Plate 4) Cross-bedded, shelly grainstone in the Ashfell Limestone Formation at Wilson Scar by Shap, Cumbria [NY 5406 1775] (Photograph M McCormac).

(Plate 5) Flood plain of the River Eamont from Barrackbank Wood [NY 563 293]: the terraces on the right are composed of glaciofluvial gravels. The escarpment in Penrith Sandstone Formation in the distance is in the adjacent Penrith district (L788).

(Plate 6) Gypsum karst in the B-bed within the Eden Shales Formation, formerly exposed in 1935, in McGhie's Quarry [NY 642 268], near Kirkby Thore. The quarry face is 3.7 m high. (A6558).

(Front cover) The southern part of the Haweswater Reservoir and Harter Fell viewed from Mardale Banks [NY 480 125]. The reservoir occupies a major glacial trough cut into rocks of the Borrowdale Volcanic Group (Photograph D Millward).

(Rear cover)

Figures

(Figure 3) Details of the Birker Fell Formation

(Figure 4) Details of the Scalehow, Whelter Knotts and Mardale formations

(Figure 5) Details of the higher formations of the Borrowdale Volcanic Group in the district

(Figure 6) Details of the Borrowdale Volcanic Group and Windermere Supergroup lithostratigraphy in the Cross Fell inlier (after Burgess and Holliday, 1979)

(Figure 7) Devonian and Carboniferous rocks of the Appleby district

(Figure 8) Details of the Permian and Triassic rocks of the district

(Figure 10) Details of intrusive rocks in the district

(Figure 11) Mineralisation and summary of mining history in the Appleby district