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Geology of the Kendal district — brief explanation of the geological map Sheet 39 Kendal

D Millward, M McCormac, N J Soper, N H Woodcock, R B Rickards, A Butcher, D Entwisle and M G Raines

Bibliographic reference: Millward, D, McCormac, M, Soper, N J, Woodcock, N H, Rickards, R B, Butcher, A, Entwisle, D, and, Raines, M G. 2010. Geology of the Kendal district —a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 39 Kendal (England and Wales).

Keyworth, Nottingham: British Geological Survey. Printed in the UK for the British Geological Survey by B&B Press Ltd, Rotherham. © NERC 2010 All rights reserved

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(Front cover): Longsleddale. Borrowdale Volcanic Group rocks of Goat Scar with glacial and fluvial deposits alongside the River Sprint. (Photographer F I MacTaggart; P668841).

(Rear cover)

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

Notes

The word 'district' refers to the area of the geological 1:50 000 Series Sheet 39 Kendal. National grid references are given in square brackets. In this account lithostratigraphical units and structures named on the maps are shown in bold type. Symbols with round brackets after lithostratigraphical names are the codes as used on the geological map.

Acknowledgements

This Sheet Explanation was compiled mainly from BGS reports listed in the Information sources section. The farmers and landowners are thanked for their co-operation and assistance during the resurvey.

The text was edited by M A Woods and J E Thomas; figures were drawn by S W Horsburgh and pagesetting was by A R Minks.

The grid, where it is used on figures, is the National Grid taken from Ordnance Survey mapping.

Crown copyright reserved Ordnance Survey licence number 100017897/2010.

Geology of the Kendal district (summary from the rear cover)

(Rear cover)

An explanation of Sheet 39 (England and Wales) 1:50 000 series map

The Kendal district of Cumbria encompasses the picturesque mountain valleys of Troutbeck, Kentmere and Longsleddale within the Lake District National Park, and the Howgill Fells, part of which lie in the Yorkshire Dales National Park. The local economy of this rural area is dominated by hill farming and tourism. Major rail and road links between the north and south of Britain cross the area. Some limestone and sandstone resources in the district are extracted for crushed rock aggregate, whilst small reservoirs provide valuable public water supplies.

Lower Palaeozoic igneous and sedimentary rocks are overlain in the north-east and south around Kendal by Carboniferous sedimentary rocks. In the north, the Early Devonian Shap Granite is one of the best known igneous rocks in Britain. There is a strong relationship between landscape and geology, with the volcanic-, sandstone-, mudstone- and limestone-dominated rock units each carved into distinctive landforms. New work on the 450 million year old Borrowdale Volcanic Group extends our knowledge and understanding of the nature of the volcanism, depositional processes and environment operating during this very short but explosive period of Earth history. New information on the Upper Ordovician and Silurian sedimentary strata provides a detailed contribution to our understanding of the Acadian Orogeny in northern England.

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

The new geological maps ('Bedrock' and 'Bedrock and Superficial Deposits') and this Sheet Explanation complete the resurvey of the Lake District Lower Palaeozoic inlier and 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 and water resources, and foundation conditions.

Chapter 1 Introduction

This Sheet Explanation summarises the geology of the district covered by the 1:50 000 geological Sheet 39, Kendal, published in Bedrock, and Bedrock and Superficial Deposits editions in 2007 and 2008 respectively. Further details of the geology may be found in the Technical reports listed in the Information sources section and in other literature cited in the text.

The Kendal district is a mainly rural part of Cumbria where the local economy is dominated by farming, though tourism is also particularly important. Significant resources of limestone, sandstone and igneous rock are currently exploited. The main settlements include the small towns of Windermere in the west, Sedbergh in the south-east, and the former Westmorland county town of Kendal, which lies in the south-central part and serves as the southern gateway to the Lake District National Park. The margin of the Yorkshire Dales National Park lies in the east of the district. Major arterial transport routes linking the north and south of Britain, including the M6 motorway and mainline railway, follow the Lune valley for part of their route through the district.

The main river catchments draining the district southwards are those of the Kent and Lune; Windermere borders the west of the district, and Trout Beck and its tributaries drain into it. Surface water bodies include Fisher and Kentmere tarns, and small reservoirs at Dubbs, Kentmere and Killington, which provide public water supplies. Killington Reservoir holds some 3.5 million cubic metres of water, which is fed to the Lancaster Canal, the largest canal reservoir when it was completed in 1819.

There is a strong relationship between landscape and geology in the Kendal district. High peaks and glacially sculpted valleys in the north and north-west are underlain by the Ordovician Borrowdale Volcanic Group, the oldest rocks exposed in the district. However, the largest part of the district is underlain by younger marine mudstone and sandstone of the Upper Ordovician and Silurian Windermere Supergroup. In the central and southern parts these rocks give rise to mostly gently undulating terrain, but in the east, resistant sandstones within the core of a major anticlinal structure form the foundation of the Howgill Fells, the only high massif formed by these rocks (Plate 1). Further contrast is found in the Carboniferous limestone successions in the north-east and around Kendal, where terraced hillsides locally display well-developed karstic features. Widespread Quaternary deposits blanket the bedrock, notably in the south-east where ice movement has moulded the till into fields of drumlins.

In Ordovician (Caradoc) times, northern England lay at the margin of Avalonia, and as the Iapetus Ocean to the north closed, immense volumes of subduction-related mafic and silicic lavas, and pyroclastic rocks were erupted in the Lake District region during a magmatic episode that lasted for less than 5 million years. Remnants of these subaerial caldera volcanoes now comprise the Borrowdale Volcanic Group, the uppermost part of which is preserved in the north of the Kendal district. A major granitic batholith was emplaced beneath the volcanic sequence at this time. After magmatism had ceased, thermal subsidence re-established marine conditions and a flexural foreland basin developed during final closure of the Iapetus Ocean. Huge volumes of sand, silt and mud turbidites were deposited in this basin to form the Windermere Supergroup (Plate 2).

Sinistral transtension across the region during latest Silurian and Early Devonian times allowed thick sequences of coarse clastic rocks of Old Red Sandstone-type to accumulate, though all were eroded from the district subsequently. The Lower Palaeozoic rocks were then folded, faulted and cleaved during the brief Acadian Orogeny at about 400 Ma. The Shap Granite Pluton and its associated dyke swarm were emplaced towards the end of the deformation period. Uplift, erosion and deposition of further red-bed sediment followed in ?Mid and Late Devonian to early Carboniferous times; the sedimentary record of this episode is preserved only locally in troughs.

During early Carboniferous times, about 350 Ma, the north-east of the district lay within an extensional trough and shallow marine conditions were established here and across the southern flank of the Lake District Block. Coastal plain, peritidal and lagoonal bioclastic carbonate rocks dominate the sedimentary record of this period, but in late Arundian times a fluviodeltaic system spread into the north-eastern part of the district. Elsewhere, repeated marine transgressions established inshore, marine carbonate ramp environments that progressively inundated the Lake District Block in Holkerian to Asbian times. By the late Asbian, the carbonate ramp had evolved into a platform with water depths of generally less than 20 m.

Rocks of mid Carboniferous to Cenozoic age are absent from the district. Studies of the rock record in adjacent areas have shown that from Brigantian to mid Westphalian times, the supply of river-borne terrestrial sediment balanced local subsidence sufficiently to maintain a deltaic environment with episodic marine incursions. Deformation and uplift terminated sedimentation at the end of the Carboniferous as a result of changing plate configurations far to the east and to the south where in southern Britain a thrust stack raised the Variscan mountain belt. At this time, uplift along the Dent Fault Zone brought older rocks to a high structural level, and imparted a westward plunge to all the Acadian structures in the Windermere Supergroup adjacent to the fault in the eastern part of the Kendal district.

To the north of the district, early Permian aeolian and fluvial sands accumulated in the Vale of Eden basin as a result of extensional faulting along the Pennine and Dent fault zones. Further subsidence in late Permian times resulted in dominantly lacustrine and continental sabkha environments and evaporite deposition, and this was followed by fluvial and aeolian sedimentation in the Early Triassic. Continued subsidence eventually established widespread marine con-

ditions in northern England by the Early Jurassic, but the region became emergent once again from the Mid Jurassic to Early Cretaceous. The mid Cretaceous opening of the North Atlantic Ocean led to widespread shelf conditions with deposition of the Chalk across the region. However, erosion that followed emergence at the end of Cretaceous times removed all post-Visean strata from the district. The main topographical elements of the district, especially the Lake District and Howgill Fells, and the major river systems, were initiated during this time.

Quaternary glaciations sculpted the impressive landforms that characterise the region. 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 north of the district during the Loch Lomond Stadial (11000 to 10 000 years ago) before renewed amelioration of the climate brought about complete deglaciation at the onset of the Holocene.

Survey history

The primary survey of the Kendal district, undertaken in the 1860s at a scale of six inches to one mile, was published as Quarter Sheet 98 NE (one inch to one mile) in 1871 with an accompanying memoir. The superficial deposits were resurveyed subsequently and revised editions of the map and memoir were published in 1888.

The current survey of the district began during the 1980s with examination of the Windermere Supergroup in the area around Kentmere and Crook, and of the Carboniferous rocks in the north-east. The remainder of the resurvey took place from 1995 to 2000. Mapping of the Windermere Supergroup was completed mainly under contracts to Sheffield and Cambridge universities.

Chapter 2 Geological description

Concealed geology

Information on the concealed geology of the Lake District is provided by interpretations of regional gravity and aeromagnetic data by Lee (1986, 1989). The contoured geophysical maps shown in (Figure 1)a and b are based on sources listed in the Information sources section. The general northward decrease in gravity values across the district (Figure 1)a is mainly due to the presence to the north of the largely concealed, low density, Lake District granitic batholith within denser Lower Palaeozoic host rocks. Southward thinning of the Silurian sequence above denser Ordovician rocks and crystalline basement may also contribute to the gradient (Lee, 1989). The local gravity minimum, close to the northern edge of the district, is associated with the Shap Granite Pluton. Geophysical modelling suggests that this is a steep-sided intrusion which extends to a depth of about 9 km; a shallow roof region is interpreted to underlie the metamorphic aureole on the southern side of the pluton, extending about 1.5 km to the south of its outcrop (Lee, 1989). Cutting south-west to north-east through the southern boundary of the Shap Pluton is the Southern Borrowdales Lineament. This is observed in the north-west quadrant of the district as a line of subtle gravity contour inflections related to the density contrast between the Borrowdale Volcanic Group to the north and the Windermere Supergroup to the south, which are juxtaposed in the steep limb of the south-facing Westmorland Monocline. Like the Crummock Lineament in the northern Lake District, the Southern Borrowdales Lineament probably represents a major, deep-seated fracture, which has been reactivated at various times, influencing the development of Borrowdale volcanism and the emplacement of the Shap Pluton (Lee, 1989).

The Shap Pluton is associated with a strong magnetic anomaly (Figure 1)b, which is best explained by the combined effects of a granite with moderate magnetic susceptibility and high-susceptibility volcanic rocks within the adjacent metamorphic aureole (Lee, 1989).

The longer wavelength magnetic high in the south-western part of the district was interpreted by Lee (1989) to be due to concealed magnetic basement at a depth of about 5 km. Regional geophysical images indicate that this feature lies at the northern end of a north-west to south-east orientated magnetic anomaly that extends from the Furness area to Norfolk. This anomaly is truncated against the Southern Borrowdales Lineament. There is widespread magnetic basement beneath central Britain, which is interpreted to be of Precambrian (Avalonian) age (Kimbell and Quirk, 1999). The Furness–Norfolk axis may be due to a ridge in this basement; to overlying early Palaeozoic magnetic metasedimentary rocks, perhaps similar to the magnetite-bearing rocks encountered in the Beckermonds Scar Borehole in North Yorkshire (Wilson and Cornwell, 1982); or to magnetic igneous rocks associated with Late Ordovician arc magmatism resulting from the closure of the Tornquist Ocean to the north-east.

Ordovician

Borrowdale Volcanic Group (BVG)

The Borrowdale Volcanic Group comprises andesitic and dacitic lavas, sills, and pyroclastic and volcaniclastic sedimentary rocks in a succession probably more than 3500 m thick in the Kendal district. The lava-dominated lower part of the group (Millward, 2004a) is not present here, where only formations from within the dominantly volcaniclastic upper part of the group crop out (Figure 2). The Upper Ordovician (Caradoc) succession was emplaced in subaerial and shallow subaqueous environments and the numerous thick sheets of welded, silicic pyroclastic rocks are the product of caldera-forming eruptions. Understanding of the stratigraphy of the volcanic succession has changed radically since previous work in the area. Many of the andesite units, previously interpreted as lava, have now been recognised as sills. Correlation with previous lithostratigraphy in the district is given in Millward (2004b).

The oldest volcanic rocks in the district crop out south-west of Small Water [NY 455 100] and comprise part of the Mardale Sandstone Formation (Mrl). In the Haweswater area to the north, this overlies an earlier formed caldera-related succession (Millward, 2004a). A subsequent large-magnitude ignimbrite-forming event produced the succeeding Froswick Tuff Formation (Fsw). Complex eruption dynamics produced systematic variations in the volume of pumice and lithic clasts with, in particular, a coarse lithic breccia facies at the base.

The pyroclastic lithofacies and restricted distribution of the Woundale Tuff Formation (Wou) are indicative of phreatomagmatic fallout and pyroclastic density current deposits, and part of the succession may represent remnants of tuff cones. Erosion features and the markedly unconformable relationships with the overlying strata imply subaerial emplacement. The typically thin-bedded upper part containing many beds of vesiculated coarse tuff, is referred to the Doup Crag Tuff Member (DpT). A 30 m-deep, 300 m wide, palaeovalley cut into the top of the formation is filled by the glassy Threshthwaite Crag Tuff (TshC).

The outcrop of the Seathwaite Fell Sandstone Formation (Set) in the Kendal district is the eastward extension of a very thick succession of stratified volcaniclastic sedimentary rocks seen to the west (Millward et al., 2000). The thickness of the formation decreases abruptly across the Troutbeck Fault, and the sequence becomes much disrupted by andesite sills. The lower part of the formation is coarse grained and weakly bedded with characteristics of rapid sedimentation, whereas the upper part is finer grained, and generally well bedded, with fluvial characteristics.

Two important pyroclastic units occur within the upper part of the formation. The distinctive white-weathered Wrengill Quarry Tuff is too thin to be shown clearly on the 1:50 000-scale map, but consists of beds of silicic accretionary lapilli-tuff previously referred to as the 'Bird's Eye Kentmere Slates'. This tuff is a valuable stratigraphical marker throughout the district, revealing much about the architecture of the formation and the scale of its bounding unconformities. Though it has similar characteristics to the Glaramara Tuff of the central Lake District (Millward, 2004a), the Wrengill Quarry Tuff represents a later silicic event, probably erupted from a vent in the east. The St Raven's Edge Tuff Member (SRE) is an andesitic ignimbrite local to the north-west of the district, lying just above the Wrengill Quarry Tuff.

The welded silicic pyroclastic rocks of the Kentmere Pike Tuff Formation (Kmr) are localised to the area between Kentmere and Longsleddale and are much disrupted by andesite sills.

The lower part of the Wet Sleddale Andesite Formation (WetS) comprises massive andesite alternating with blocky autobreccia, and this is succeeded by sheets of scoriaceous, autobrecciated and highly amygdaloidal basaltic andesite. Interstices in the autobreccia are filled by laminated fine-grained sandstone. The relationship along some of the upper contacts is indicative of intrusion, whereas other contacts and the presence of intercalations of pyroclastic rock of similar composition to the sheets are compatible with emplacement as lava. The Wet Sleddale Formation is interpreted as a lava pile that may contain a significant proportion of sills. The western limit of the formation is shown to be faulted, but the large number of shallow sills immediately to the west may have been contemporaneous.

The Lincomb Tarns Tuff Formation (LTa) is the most widespread and voluminous pyroclastic formation in the Borrowdale Volcanic Group, with a present outcrop of at least 500 square kilometres (Millward, 2004a). Though apparently conformable basal relationships are evident in places in the Kendal district, the Lincomb Tarns Formation rests on a major erosion surface which locally had at least 250 m of topographical relief.

A single ignimbrite sheet comprises the formation from Kirkstone Pass to Stony Cove, but to the south, from The Hundreds to Longsleddale, two major ignimbrite sheets are separated in the west by bedded volcaniclastic rocks, 50 to 160 m thick, and in Longsleddale by the partly intrusive, partly extrusive, Goat Scar Dacite Member (GSD). It is uncertain whether these two breaks in ignimbrite-producing eruptions were coeval. The lower ignimbrite is from 300 to 680 m thick and the upper one up to 240 m.

The Esk Pike Formation (EsP) in the Kendal district is markedly thinner than that seen elsewhere in the Lake District; as a consequence it is preserved mainly in irregularities in the upper surface of the underlying formation. The sandstone is composed of mainly andesitic detritus derived from a source other than the underlying dacitic Lincomb Tarns Formation; its provenance is probably related to contemporaneous andesitic activity elsewhere in the Lake District.

The coeval Middle Dodd Dacite (MDD) and Garburn Dacite (GaD) formations are the youngest extrusive volcanic units preserved in the district. The former is restricted to a 600 m-wide, northerly trending graben on the east side of the pass on Caudale Moor [NY 410 099], in the north-west, whereas the latter is more extensive, lying beneath the unconformity at the top of the Borrowdale Volcanic Group. Both are considered to be lava flows.

Dent Group (Dnt)

The Dent Group constitutes the Ordovician (Ashgill) component of the Windermere Supergroup (Figure 3). The strata represent a transgressive succession of shallow marine shelf sediments that encroached across the eroded, irregular unconformity at the top of the Borrowdale Volcanic Group. Four depositional cycles are present, each with a non-sequence beneath its base representing emergence and erosion, followed by deposits indicative of submergence in increasing water depth (Kneller et al., 1994). Just to the east of the district, in the Cautley and Dent inliers, the first three cycles are represented by the Cautley Mudstone Formation which was deposited continuously in deeper, oxygenated marine conditions (Rickards and Woodcock, 2005). This formation, and thus the Dent Group as a whole, thins significantly and changes facies north-westwards across the Kendal district as shown in the cross-sections on the bedrock map.

The first cycle begins with the Stile End Formation (SEn), preserved only within irregularities in the volcanic substrate. The basal Longsleddale Member (Lsd) resulted from the local progradation of alluvial fans into an embayment of the sea, where wave action reworked the deposits. In the rest of the formation, coarse volcaniclastic sediment deposited in the nearshore region becomes gradually finer grained offshore, passing into a belt where calcareous mud accumulated.

The later stages of this first cycle were punctuated by a brief episode of silicic volcanism. The Yarlside Volcanic Formation (Yrl) is the most voluminous of several Ashgill volcanic sequences in the Lake District and adjacent areas and occurred 5 to 10 million years after Caradoc volcanism had ceased. Emplacement of the formation caused emergence and detrital material from it was reworked into the base of the overlying Kirkley Bank Formation. The Rb-Sr whole-rock isochron age of 421±3 Ma is, in common with those of many other igneous rocks in the Lake District, considered to have been reset (Stone et al., 1999 and references therein).

The second depositional cycle is represented by the Kirkley Bank Formation (Plate 3), and resulted in the complete burial of the Borrowdale Volcanic Group across the district. The formation contains a more abundant and varied shelly fauna than preceding rocks. McNamara (1979) listed more than thirty species of trilobites, corals, brachiopods, gastropods, bryozoans, ostracods and crinoids from the formation, and considered that these are indicative of the Cautleyan Stage, Zone 2 and lower Zone 3 of Ingham (1966).

An hiatus of four of the Cautley to Rawtheyan benthic macrofaunal biozones of Ingham (1966) indicates that the third depositional cycle was removed from the northern part of the Kendal district by erosion. The overlying, apparently conformable, Ashgill Formation was deposited during the fourth cycle. This formation is so thin that it is shown with the underlying Kirkley Bank Formation as undivided Dent Group on the bedrock 1:50 000-scale map. The base of the Ashgill Formation is defined by the base of the Troutbeck Member, a calcareous siltstone with a distinctive fauna that includes monospecific bedding-plane assemblages of the trilobite Mucronaspis and the brachiopod Hirnantia. The remainder of the formation is sparsely fossiliferous and is distinguished from the underlying rocks by the pervasive bioturbation, its generally lower calcareous content and the near absence of limestone nodules. The Troutbeck Member is youngest Rawtheyan, but the overlying rocks belong to the Hirnantian Stage.

Silurian

Silurian strata in the Kendal district form the upper and substantially thicker part of the Windermere Supergroup (Figure 4). In this account, the graptolite biozonation follows the scheme of Rickards and Woodcock (2005). The Stockdale Group (Stk), divided into the Skelgill and Browgill formations, is seen throughout the Lake District and comprises strata of latest Hirnantian and Llandovery age (Kneller et al., 1994). In the Kendal district, this succession forms a very narrow outcrop and because of this, the group is depicted undivided on the 1:50000-scale map.

The thinly laminated black mudstone that dominates the lower part of the Skelgill Formation is organic-rich and contains a prolific graptolite fauna. The pale argillaceous basal beds that are well exposed in Brow Gill [NY 4974 0587] are referred to the Spengill Member which is believed to belong to the persculptus Biozone and hence latest Ordovician, whilst the overlying beds range up to the early Silurian sedgwickii Biozone (Rickards and Woodcock, 2005).

Some thin K-bentonite beds are also present, representing altered, fine-grained volcanic ash deposits many hundreds of kilometres from the source of their Plinian eruptions.

Thinning of the Skelgill Formation within the district is ascribed primarily to the presence of an almost bedding-parallel tectonic detachment referred to elsewhere in the Lake District as the Stockdale Thrust (see Lawrence et al., 1986). Strikingly, the thrust seems to be confined to the weakest black mudstone at or about the level of the triangulatus Biozone.

The greyish green mudstone of the Browgill Formation yields a rich graptolitic fauna indicating a Telychian age. Though there is some bioturbation, most beds are well laminated with carbonaceous layers. The uppermost, and apparently unfossiliferous mudstone beds are referred to as the Far House Member. There are also many K-bentonite beds, particularly in the lower part.

The Tranearth Group dominantly consists of finely laminated hemipelagic mudstone and siltstone constituting the Brathay and Wray Castle formations, separated by a turbidite sandstone unit of the Birk Riggs Formation and a thin calcareous siltstone unit of the Coldwell Formation. The sub-millimetre-scale alternations of organic-rich mud and quartzose silt in the Brathay Formation (BrF) are interpreted as hemipelagic deposition in still, anoxic conditions, with no bioturbation. Interbedded, organic-poor mudstone beds, a few centimetres thick, represent low-volume, dilute turbidite deposits. Laminae and thin beds of K-bentonite occur throughout the formation, and are thought to have been deposited through the reworking of pyroclastic deposits by turbidity currents. Graptolites collected from the formation indicate an age range from basal centrifugus Biozone up to the lundgreni Biozone of the Wenlock (Rickards and Woodcock, 2005; Lawrence et al., 1986, and references therein).

The Birk Riggs Formation (BkR) is overstepped eastwards by the Coldwell Formation on Scour Rigg [NY 4456 0368], towards Kentmere, but reappears a little to the east in Longsleddale [NY 4782 0468] to [NY 5000 0582]. It is not seen east of Brow Gill, in the Shap and Howgill fells (Figure 5), where the laminated facies of the Brathay Formation passes up directly into the Coldwell Formation, showing that turbidite sandstones equivalent to the Birk Riggs Formation are not developed there. Faunas from the Birk Riggs Formation indicate a lundgreni Biozone age (late Wenlock; Lawrence et al., 1986, and references therein).

The Coldwell Formation (Cdw) is typified by the presence of two units of bioturbated calcareous siltstone with a shelly fauna, separated by a sequence of Brathay-type hemipelagic mudstone with graptolites. Most of the primary lamination has been destroyed by bioturbation, producing a mottled appearance. These characteristics and its tendancy to form a ridge, sometimes double, make the formation a valuable marker across the region. In the Kentmere area the formation spans the nassa and ludensis biozones (Rickards, 1970), while in the eastern Howgill Fells a ludensis age has been established for the lower part and a nilssoni Biozone age for the upper part (Rickards and Woodcock, 2005 and references therein). Thus, the formation might be weakly diachronous across the district, but nonetheless spans the Wenlock–Ludlow boundary.

The hemipelagic Wray Castle Formation (Wre) is lithologically similar to the Brathay Formation, though with a higher proportion of silt and thicker lamination. Thickness changes across the district reflect the diachronous base of the overlying Coniston Group. In the southern Shap Fells the lowest sandstone in the Coniston Group (Gawthwaite Formation) dies out eastwards and the higher part of the Wray Castle Formation extends upwards and becomes laterally equivalent to the Latrigg Formation. The siltstones yield a nilssoni Biozone (early Ludlow) graptolite assemblage (Rickards and Woodcock, 2005).

The Coniston Group (Ctg) comprises greenish grey, micaceous, fine- and medium-grained sandstone beds in units tens of metres thick, interbedded with thin units dominated by laminated hemipelagic mudstone in the group's lower part, and by banded siltstone–mudstone couplets in its upper part. These rocks are interpreted as the deposits of sandy, turbiditic submarine fan systems. The succession includes rocks of the Gorstian stage and lies within the nilssoni, scanicus and soperi biozones (Rickards and Woodcock, 2005).

In the western part of the district, the Coniston Group is divided into three sandstone-dominated formations (Gawthwaite, Gte; Poolscar, Psr; Yewbank, Ybk), separated by finer grained units (Latrigg, Lrg; and Moorhowe Mho formations). East of Longsleddale, this 'standard' stratigraphy breaks down because the Gawthwaite and Moorhowe formations cannot be recognised (Figure 5). Hence, from Longsleddale eastwards to Shap the group is not divided formally. In the Howgill Fells the Coniston Group succession is again divided on the basis of the thickness of the component sandstone beds and particularly on the proportion of laminated hemipelagic siltstone that persists in the sequence (Rickards and Woodcock, 2005). There, three hemipelagite-rich units divide the group into four sandstone-rich packages, only the lowest of which, the Screes Gill Formation (SGi), is named.

The Kendal Group (Rickards and Woodcock, 2005) is more than 4200 m thick and comprises the Bannisdale and Kirkby Moor formations. With a range of environments from basinal marine at the base, to intertidal at the top (King, 1994), these formations represent a greater diversity of depositional settings compared with the other divisions of the Windermere Supergroup. The base of the group coincides with that of the Bannisdale Formation, is gradational and, in parts of the outcrop, difficult to recognise. The predominantly thin-bedded turbiditic rocks that characterise the Bannisdale Formation (Bnd) are interbedded in places with packets of thick-bedded turbiditic sandstone superficially similar to those in the underlying Coniston Group. This problem is particularly evident south of Sedbergh.

In this study, the Underbarrow Formation of Shaw (1971) is abandoned as a lithostrati-graphical unit; bioturbation and shelly lags regarded as typical of this formation occur sporadically throughout the passage from the deep-water 'banded' facies of the Bannisdale Formation, into the overlying storm-dominated shelf and subtidal sandstones of the Kirkby Moor Formation (KMF). The lowest 100 m of the Kirkby Moor Formation have been mapped as a discontinuous, unnamed basal member in the core of the Bannisdale Syncline: these strata are thin bedded, with parallel and ripple cross-lamination, occasionally swaley and hummocky cross-stratification, and shallow channels locally.

Devonian

Old Red Sandstone-lithofacies rocks (Figure 6) are preserved locally in troughs along the unconformity that separates the Lower from the Upper Palaeozoic strata in the district. These red-bed facies, along with the Mell Fell Conglomerate in the northern Lake District, are considered to be Middle to Upper Devonian, but diagnostic fossils have not been recorded. Deposition in a pluvial desert environment occurred in coalesced alluvial fans and braided river beds (Capewell, 1955), probably against fault scarps active during the final stages of the Acadian Orogeny (Soper and Woodcock, 2003).

In the north-east of the district, beds of cobble conglomerate forming the lower part of the Shap Wells Conglomerate Formation (ShWC) appear to be banked against the western flank of a palaeovalley. These rocks are overlain by those of the Blind Beck Sandstone Member (BBkS) which contains a large component of well-rounded sand grains with hematite pellicles (Capewell, 1955), evidence of aeolian transport. At the classic locality in the grounds of the Shap Wells Hotel [NY 5774 0980], the sandstone beds rest directly on an uneven surface of Windermere Supergroup rocks.

Around the town of Sedbergh [SD 655 920], in the south-east of the district, the Sedbergh Conglomerate Formation (SdCo) contains a mixed assemblage of Borrowdale Volcanic Group, Windermere Supergroup and granitic clasts. Mean palaeocurrent directions show dispersal towards the west-north-west, turning east to west close to the northern outcrop margin. To the east of Sedbergh, the conglomerate is overlain by fluvial sandstone with bedded and nodular calcrete, a facies common to the Upper Devonian and lower Carboniferous (Tournaisian) strata of the Northumberland Basin.

Carboniferous

Sedimentary rocks of Tournaisian and Visean age rest unconformably on older rocks across the north-east of the district and within faulted outliers to the west and north-east of Kendal. The succession consists of up to 800 m of fluvial arenite and shallow marine carbonate rocks comprising the Ravenstonedale Group, and carbonate ramp and platform deposits of the Great Scar Limestone Group.

The Ravenstonedale Group includes rocks of Courceyan, Chadian and Arundian age, laid down within a shallow marine embayment at the western limit of the Stainmore Trough, and across the northern, shelf margin of the Craven Basin. Coastal plain, peritidal and lagoonal bioclastic carbonates predominate, but a fluviodeltaic system spread into the district from the north-east in late Arundian times (Leeder, 1982). The group is 180 to 250 m thick in the north-east of the district, where four formations are recognised (Figure 6), but only 90 to 170 m thick in the Kendal area, where basal Courceyan and Chadian beds only are preserved (Figure 7).

The oldest unit within the Ravenstonedale Formation is the Pinskey Gill Formation (PnkG) which rests unconformably on a smooth, north-dipping basement surface in the north-east. These rocks were deposited during the first Carboniferous marine incursion. The succeeding, laterally variable clastic succession of the Marsett Formation (MaSa) oversteps the Pinskey Gill Formation to overlie Lower Palaeozoic or Devonian rocks throughout the rest of the district. Mudstone beds at the top of this formation pass upwards into the peritidal Stone Gill Limestone Formation (Ste). The equivalent supra- to peritidal rocks to the west and north-east of Kendal (Figure 7) comprise the Martin Limestone Formation (MtL). A Courceyan to Chadian age is indicated from palynological studies (Holliday et al., 1979) and from the occurrence of the coral Dorlodotia (Thysanophyllum pseudovermiculare (McCoy) of Garwood, 1913) at the top of the Martin Limestone. The uppermost part of the group is the Ashfell Sandstone Formation (AfL). This unit forms a bench feature along much of its outcrop that is punctuated by many disused shallow workings for sandstone. Thin calcareous interbeds contain a coral–brachiopod fauna indicating a late Arundian age (Garwood, 1913). The Great Scar Limestone Group results from repeated marine transgressions which established shallow, inshore marine ramp environments in late Chadian, Arundian, and more extensively, in Holkerian to Asbian times, when all but the core of the Lake District Block was inundated (M Mitchell, in Moseley, 1978). During late Asbian times the carbonate ramp evolved into a platform with water depths generally less than 20 m. Wide areas of the platform became emergent during lowstands, and developed karstic surfaces, some of which were overridden by fluviodeltaic sediment. The group is up to 590 m thick in the north-east of the district, divided into seven formations (Figure 6) which show progressive thinning from east to west across the outcrop; up to 245 m of strata in three formations occur in the Kendal area (Figure 7).

In the Orton area, the base of the late Chadian Coldbeck Limestone Formation (Clk) is defined by a unit of thin-bedded limestone with siltstone interbeds containing the 'Algal Band' of Garwood (1913). The outcrop of the formation within the district is largely obscured by superficial deposits and the formation limits are conjectural. The Scandal Beck Limestone Formation (ScBL) comprises two lithologically distinct parts. The lower part is dominantly wavy, thin-bedded dolostone and packstone, whereas the upper part is a thick, rhythmically bedded dark grey wackestone, which is markedly bituminous, and contains colonies of the coral Dorlodotia (Plate 4).

The Brownber Formation (BnbF) outcrop is mainly till-covered. Beds of flaggy, calcareous sandstone and siltstone/mudstone comprise up to three coarsening-up cycles. Interbedded with the sandstone are beds of sandy and ooidal limestone grading into cross-bedded, very coarse-grained calcarenite or calcirudite containing conspicuous, well-rounded clasts of quartz and calcite.

The Breakyneck Scar Limestone Formation (Bre) thickens south-eastwards into the axis of the Stainmore Trough. The dark grey shelly limestone interbedded with dark grey mudstone contains an early Arundian fauna. The equivalent rocks in the Kendal area belong to the Dalton Formation (DlB), a thick, marine succession of dark grey, well-bedded crinoidal grainstone with thin interbeds of siltstone that form the bold escarpment at Cunswick and Scout scars.

The Ashfell Limestone Formation (AfL) contains an abundant coral, brachiopod and gastropod fauna, including the incoming of the diagnostic Holkerian species Lithostrotion minus (McCoy) and Davidsonina carbonaria (Phillips). The top of the formation is marked by the 'Bryozoa Band' of Garwood (1913), comprising cross-bedded crinoidal grainstone, grey mudstone with bivalves, and vuggy porcellanous limestone. The equivalent rocks in the Kendal area are assigned to the Park Limestone Formation (PkL), which forms a cap to Kendal Fell, a prominent feature to the west of the town. The basal Kettlewell Crag Member (KeCr) is a shelly coarse-grained grainstone with black silty partings and common remains of the brachiopod 'Cyrtina carbonaria'. The formation typically weathers to a block-field or scree-mantled karst.

The well-jointed, pale grey packstone/ wackestone of the lower Asbian Potts Beck Limestone Formation (PBL) is cyclically bedded and commonly contains mottled calcrete textures. Poorly exposed beds of sandstone and mudstone occur within the succession and a thin sandstone unit separates the Potts Beck Limestone Formation from the overlying Knipe Scar Limestone Formation. The Potts Beck Limestone has a fauna of corals and brachiopods, including the corals Siphonodendron junceum (Fleming), Palaeosmilia murchisoni (Edwards & Haime), Axophyllum and Dibunophyllum.

The Knipe Scar Limestone Formation (KnL) forms rocky escarpments and limestone pavements. The formation mostly comprises thick-bedded packstone and wackestone with wavy-bedded shelly grainstone. Thin beds of fluviodeltaic mudstone, siltstone and sandstone occur sporadically in the succession. A partly till-covered, fault-bound outcrop of nearly identical beds assigned to the Urswick Limestone Formation (UL) is present just west of Kendal town centre.

Limestones in the Knipe Scar and Urswick formations have a depositional cyclicity similar to that seen to the south in the Kirkby Lonsdale district (Horbury, 1989). Cycle boundaries are marked by palaeokarstic surfaces and stratiform, mottled calcrete textures ('pseudobreccias'); these are commonly overlain by bentonitic clay palaeosols derived from volcanic ash fallout. Fossil faunas, though sparsely represented, include Siphonodendron, Lithostrotion and Hexaphyllia coral colonies and Gigantoproductus brachiopods, which may indicate a late Asbian age, and stromatolites.

Intrusive rocks

Large volumes of magma were intruded beneath the English Lake District during two brief Palaeozoic magmatic events (Millward, 2002). During the first, Late Ordovician (Caradoc) granite plutons were emplaced beneath the Borrowdale volcanic rocks to form the core of the Lake District Batholith. These rocks only occur at depth in the Kendal district. The second event occurred some 40 to 50 Ma later in Early Devonian times, associated with the Acadian Orogeny, when the Lake District Batholith was enlarged at its margins by further granite plutons, including the Shap Granite. Dykes and other minor intrusions from both events are represented in the district (Figure 8).

Andesite (A) sills comprise an integral part of the Borrowdale Volcanic Group. Most were emplaced at shallow levels within the volcanic pile. Some may have been feeders to, or emplaced at the same time as, extrusive parts of the succession during many phases of activity. The number and aggregate thickness of sills appears to increase eastwards across the Borrowdale Volcanic Group, such that the succession in the Kendal district is the most sill-rich. Many of the thicker sills have a massive, coherent or flow-foliated centre, bound by autobreccias at the base and top. The margins are peperitic breccia in which isolated blocks and lobes of andesite are mixed with fluidised host sediment; these features typically result from the intrusion of magma into wet sediment. A handful of andesite (A) and rhyolite (R) dykes were emplaced contemporaneously with the volcanic rocks.

Though possibly connected with the Caradoc volcanic episode, the age of intensely weathered and altered dykes of silicic composition, here classed as felsic fine-grained rocks (J_O), remains uncertain. Quartz-feldspar porphyry (qfP) minor intrusions within the Borrowdale Volcanic Group near Hartrigg [NY454061] and in Hallow Bank Quarter [NY458 067] may have been emplaced during Ashgill volcanic activity, based on petrographical similarities to a lapilli-tuff unit at the base of the Yarlside Volcanic Formation.

Early Devonian minor intrusions include sills and dykes of felsic fine-grained rock (J_D), seen mainly in the Howgill Fells. Emplacement of these rocks postdates lithification of rocks of the Coniston Group (late Silurian), but predates the Acadian (Early Devonian) folding. Lamprophyre dykes (L) are widely dispersed across the Kendal district (Macdonald et al., 1985). Kersantites are concentrated locally within Borrowdale Volcanic Group rocks in Longsleddale [NY 480 070], and in Windermere Supergroup rocks in the Howgill Fells. By contrast, mica lamprophyre dykes are dispersed sporadically but more widely. The lamprophyres consistently postdate emplacement of the felsites, but it is rarely possible to demonstrate unequivocally the precleavage age of these intrusions.

The Shap Granite Pluton (G), with its distinctive, large, pink orthoclase-perthite phenocrysts, is one of the best known igneous rocks in Britain (Stephenson et al., 1999, and references therein). The intrusion is steepsided and conical in form (Lee, 1986), and was emplaced across the boundary between the Borrowdale Volcanic Group and the Windermere Supergroup after formation of the Westmorland Monocline. Radiometric evidence has proved a late Early Devonian age (Selby et al., 2008), with intrusion during the late stages of the Acadian Orogeny (Soper and Woodcock, 2003).

Microgranite (F^G) dykes are dispersed in a radial pattern centred on the Shap Granite and examples can be found up to 11 km to the south of it. Dykes cut strata as high as the Bannisdale Formation. Occurrence is sporadic and individual dykes typically cannot be traced for more than a few tens of metres along strike. The dykes are considered to be contemporaneous with the granite pluton.

Structure

Synsedimentary and volcanotectonic deformation affected many parts of the Borrowdale Volcanic Group. These structures were tightened during the Early Devonian Acadian Orogeny (Soper et al., 1987). During this event typical 'slate belt' structures of folds, cleavage and associated faults were formed in the Windermere Supergroup. The principal Acadian folds in the Kendal district are the east-north-eastwards-trending Bannisdale and Castley Knotts synclines and the intervening Carlingill Anticline.

The structure in the west of the Windermere Supergroup outcrop is divided broadly into a steeply south-east dipping homoclinal region to the north, and an area to the south where a wide variety of fold styles, including trains of tight anticlines and more open synclines alternate with belts of rolling strata, in which the enveloping surface is subhorizontal. The boundary between these areas is the axial zone of the Bannisdale Syncline. Eastward plunge of the syncline brings in the Kirkby Moor Formation. Its outcrop comprises steeply south-dipping strata bound to the south by an upthrust fault which juxtaposes northward dipping Bannisdale Formation strata of the south limb against subvertical, southward-younging Kirkby Moor Formation. The approximately constant width of the Kirkby Moor Formation outcrop suggests that the plunge of the syncline becomes horizontal for much of its trace.

In the east of the district, resistant Coniston Group rocks are brought to outcrop again by the Carlingill Anticline and complementary Castley Knotts Syncline. Both comprise zones, at least 1000 m wide, of multiple, gently plunging hinge zones. The hinge zones of the major folds are about 4 to 5 km apart and contain homoclinal limbs as much as 2 km in cross-strike width. However, more commonly, these limbs are affected by subsidiary folds with wavelengths between about 100 m and 500 m. Two particularly large subsidiary folds are the west-plunging Farfield Syncline, and the west-plunging Winder Anticline on the south flank of Winder [SD 6544 9288]. The axial planes of all the Acadian folds are near vertical.

The Acadian folds are associated with an approximately axial planar cleavage. This trends slightly north of east in the northern and western parts of the district, roughly east–west around and to the east of Kendal, and slightly south of east in the south-east of the district. The district thus represents a nexus between the Caledonoid trend typical of the Lake District and the east-south-east-trending structures of the Howgill Fells and Ribblesdale. The cleavage transects the folds at a small angle, so that it typically lies up to 15° clockwise of the fold axial traces, though in places in the south-east of the district the angle varies up to 35°. Clockwise transection is typical of the Lake District, whereas in Ribblesdale, to the south-east, the transection is at a very small, anticlockwise angle (Soper et al., 1987). There are strong perturbations of the cleavage around the Shap Pluton (Boulter and Soper, 1973).

A set of anastomosing north-east-trending vertical faults dominates the structure of the volcanic rocks in the area around Mosedale [NY 500 096] and Harrop Pike [NY 500 077]. The north-westernmost of these faults divides generally north-west dipping strata in the north-west of the district from south-east dipping strata subjacent to the Windermere Supergroup. The changing bedding dip pattern between adjacent fault blocks suggests that the faults developed along the common limbs of upright folds with axial plane traces nearly parallel to the fault trend. Similar fault orientation and association with folding is also seen in the Ambleside district where they were interpreted to be back thrusts associated with development of the Westmorland Monocline (Millward et al., 2000).

A major component of the structure in the Kendal district is the long, steep fault system striking between north-north-west and north-north-east. This set of fractures is parallel to the major faults that bound the Lake District massif. Examples within the Kendal district include the Troutbeck Fault, a complex, multistranded zone that cuts across the Borrowdale Volcanic Group outcrop along a marked col in the roof of the underlying batholith. The Firbank Fault terminates the outcrop of the Kirkby Moor Formation.

In the Shap Fells, the northerly trending faults typically separate tracts with different fold patterns (Moseley, 1968). Displacement on the faults may have accompanied the folding, partitioning the strain. The amount and sense of displacement vary along the fault plane, accommodating the flexural and ductile strains associated with the folding and cleavage. It has been suggested that faults of this type formed above basement fractures that were reactivated and propagated up into the Windermere Supergroup cover during the Acadian deformation. The northerly trending faults were also ideally orientated for reactivation during Permo-Triassic extension that produced the east-dipping tilt blocks of Carboniferous strata that are characteristic of the southern Lake District. The Kendal Fault, which forms the eastern boundary of the Kendal Carboniferous block, is one such example.

The Rawthey and Sedbergh faults in the south-east are part of the Dent Fault Zone, the main trace of which is just east of the district. This fault zone includes duplexes and 'flower' structures formed at bends during late Carboniferous sinistral transpression (Woodcock and Rickards, 2003). The fault system marks the western margin of the Askrigg Block, and uplift of the flower-structure at this time produced a westward plunge to the Acadian Carlingill and Castley Knotts folds.

Extensional faults initiated during Permo-Triassic time include the Grayrigg and Skelsmergh faults which form the north-eastern boundaries of the eponymous Carboniferous inliers. These faults have curvilinear traces which are concave to the south-west and throw down in that direction, and contain Carboniferous rocks in the hanging wall. Such faults are probably shallowly listric, in contrast to the deep-seated origin inferred for the northerly trending faults described above.

Metamorphism

Hydrothermal activity, mineralisation, batholith emplacement, and low-grade regional metamorphism have, to varying extents, altered most of the Lake District Lower Palaeozoic rocks (e.g. Millward et al., 2000). In the Kendal district, there is scant evidence for the early phases of hydrothermal and low-grade burial metamorphism described from the volcanic rocks in the western Lake District. By contrast, white mica and carbonate, along with chlorite, epidote and titanite are pervasive in the Kendal district. The growth of white mica, in particular, is associated with cleavage fabrics that formed in response to the Acadian Orogeny.

Regional metamorphism of Windermere Supergroup rocks in the Kendal district is almost uniformly to lower anchizonal grade (Hirons and Roberts, 1999). Areas of upper anchizonal grade occur east of Windermere, but there appears to be no association with major folds or with the presence of high strain zones, and the higher metamorphic grade is inferred to reflect later movements on the major northerly trending faults. The pattern of metamorphic grade may require the presence of an appreciable cover of uppermost Silurian and Lower Devonian sedimentary rocks, which were eroded during late orogenic uplift (Soper and Woodcock, 2003).

A thermal metamorphic aureole surrounds the Shap Pluton for at least 1.3 km from its contact. In the absence of a modern geochemical and isotopic compositional study of the aureole, the first appearance of biotite is taken here as the outer limit of the aureole; this is typically indicated by a purplish brown hue to the rocks. Compositional control on thermal metamorphism is illustrated strongly by these rocks. Adjacent to the granite the volcanic rocks are biotite-hornfels, containing amphibole and, in aluminous volcaniclastic rocks, cordierite, whereas the pelitic Windermere Supergroup rocks are biotite-hornfels, with sillimanite, andalusite, and cordierite; the calcareous rocks of the Dent Group and Coldwell Formation are calc-silicate hornfels, containing augite, tremolite and wollastonite (Harker and Marr, 1893). Original igneous or clastic textures are preserved in the outer part of the aureole with a biotite overprint that varies in amount with bulk rock composition and distance from the granite.

Mineralisation

Compared with other areas of the Lake District, there are relatively few occurrences of mineralisation in the Kendal district. Economic base-metal mineralisation is unknown from the Borrowdale Volcanic Group rocks here, though there are abundant small veins containing quartz, carbonate and chlorite. A few, small-scale workings on lead-bearing veins, hosted by the Windermere Supergroup, possess some similarities to the lead–zinc veins farther north, which are considered to be of late Carboniferous or early Permian age (Stanley and Vaughan, 1982).

Late stage mineralisation, listed in (Figure 9), was associated with emplacement of the Shap Granite Pluton. High-temperature hydrothermal mineralisation is a notable feature in the Shap Pink Quarry [NY 558 084] (R J Firman, in Moseley, 1978). In addition, extensive low-temperature hydrothermal mineralisation has coated some joints, and filled joint and fault fissures in the granite and rocks of its thermal aureole.

Quaternary

The earliest tills seen in the district consist of gravelly diamicton and mounded sand and gravel exposed in the Kent valley and in the Lune gorge, between Tebay and the confluence with the River Rawthey. The deposits are undated, but they are overlain by Devensian lodgement till in a section in Carlin Gill [SD 623 996], suggesting that they may represent the earlier Albion Glacigenic Group. Deposits from the main Late Devensian glaciation, dominantly tills, and sand and gravel, comprise the Caledonia Glacigenic Group.

Lodgement till mantles the upper Lune valley east from Tebay [NY 620 050] into Ravenstonedale [NY 720 040]; it reaches an elevation of about 350 m on the northern flanks of the Howgill Fells. This deposit is assigned to the Penrith Till Formation of Thomas (1999). The till, characteristically moulded into low-amplitude symmetrical drumlins, is generally 2 to 5 m thick, but up to 20 m where drumlinised. Lithologically, the till is a diamicton, with pebble- to cobble-sized clasts in a grey to red-brown clay or silty-clay matrix; included are beds and lenses of sand, gravel and deformed laminated clay.

The upland valleys of Trout Beck, Kentmere (Plate 5), Longsleddale, Borrowdale, and Wasdale, and in the Howgill Fells to the east, are floored with uniform, sheeted or moundy deposits of lodgement till, known to be up to 30 m thick in Borrowdale (Kendal Till Formation). To the south, extensive areas of glacially moulded bedrock have been scoured clean of superficial deposits by repeated passage of ice sheets. However, in some areas till has been deposited as single, small coalesced groups and swarms of streamlined drumlins. The main swarm extends south from Borrowdale, across Grisedale and throughout the low ground of the Kent and Mint valleys between Staveley [SD 470 985] and Grayrigg [SD 580 972]. A further drumlin swarm crosses west through the Rawthey valley, before swinging sharply south to merge with the main swarm that follows the lower Lune valley. Orientation of glacial striae, and of crag and tail features, supports these as major ice-movement directions. Higher ground in the south is largely till free, for example Kendal Fell [SD 500 920] and Lambrigg Fell [SD 585 945].

A tightly delimited train of boulders of Shap Granite has been dispersed south from Shap Fell, across Borrowdale and Bannisdale, and along the east side of the Kent valley. Blocks have been recorded as far south as Preston in Lancashire (Goodchild, 1875).

Granite erratics are also a common feature along the Birk Beck valley [NY 590 080] and are dispersed east of the district into Ravenstonedale and beyond. Some prominent erratics close to the M6 motorway bear individual names, for example the Galloway Stone [NY 587 099].

Sand and gravel deposits of presumed glaciofluvial origin have a limited distribution in the district. Small kames and beaded eskers are found in the Birk Beck valley by Brackenhill [NY 593 065], and mounded deposits were previously worked around Kendal and close to the confluence of the Rivers Lune and Rawthey, at Ingmire Park [SD 634 919].

Ice retreat left extensive areas of glacially scoured limestone pavement exposed along the outcrop of the Great Scar Limestone Group. The most extensive, and ecologically important, pavements are found at Crosby Ravensworth Fell [NY 605 100] and Great Asby Scar [NY 650 100], but a smaller area is preserved in the south of the district on Kendal Fell [SD 490 910].

The Howgill Fells exhibit a markedly contrasting landscape compared with the ice-moulded Lakeland fells. There, slopes are rounded and the drainage dendritic, with v-shaped profiles. The valleys are draped with till deposits, showing that they developed prior to the last main glaciation, yet they have not been subjected to the glacial entrenchment and scouring seen elsewhere.

During the late glacial period, small corrie glaciers formed during the Loch Lomond Stadial and occupied north-east- to east-facing hollows around the heads of Kentmere, Longsleddale and Mardale (Sissons, 1980). Small Water [NY 455 100] represents a classic example of a moraine-dammed corrie lake. In the Howgill Fells, the ground elevation was insufficient to support Loch Lomond Stadial corrie glaciers. However, corrie-like hollows such as Cautley Crag [SD 682 967] (Manley, 1959), and Little and Great Coum on Grayrigg [SD 605 999], probably developed as nivation hollows.

Periglacial conditions prior to the most recent climatic amelioration led to the accumulation of scree aprons below crags in many of the high Lakeland fells and around Cautley and the Lune gorge in the Howgill Fells. Head deposits resulted from solifluction of the recently deposited glacial sediment. Landslides also occurred on oversteepened slopes.

During Holocene times, peat accumulated to a depth of several metres on the gently rolling high fells. Shallow, late glacial lakes, such as existed above and below the village of Kentmere [NY 457 041], were filled with alluvium (Plate 5) and by the build-up of alluvial fans at watercourse tributary intersections; the Trout Beck built a prominent delta into Lake Windermere. In Kentmere, diatomaceous deposits accumulated in lake basins at times when there was little sediment influx. These deposits are assigned to the Britannia Catchment Group.

The major rivers now largely follow water courses inherited from glaciation. The River Lune, upstream and downstream of the gorge, flows within a broad meander belt flanked by a succession of wide, low-angled alluvial terraces and tributary fans, well seen around the M6 Tebay interchange [NY 615 047] and at its confluence with the River Rawthey.

In the Howgill Fells, the late glacial deposits have been cut by streams, the development of which was marked by several phases of terrace construction. The youngest of these appears to relate to a major phase of gully development. Since then the gullies have stabilised; the streams have cut below the lowest terrace and formed the modern flood plains (Harvey, 1985). In June 1982, a brief but intense storm resulted in the deposition of a set of alluvial fans at the junction between small tributary catchments and two north-flowing headwater streams of the River Lune (Wells and Harvey, 1987).

Chapter 3 Applied geology

The Kendal district is mainly rural and the principal land use is farming. Tourism is important to the local economy, and parts of the district lie within the Lake District and Yorkshire Dales national parks, designated in 1951 following the National Parks and Access to the Countryside Act of 1949. The spectacular scenery of these areas attracts large numbers of visitors and the geological foundation of that landscape is thus the main local asset. Major transport routes linking northern and southern Britain pass through the area (Plate 6).

Mineral resources

Information in this section is summarised from Young et al. (2001). Compared with other parts of the Lake District the extraction of metalliferous minerals was not significant in the Kendal district. Small-scale working of lead-bearing veins has occurred in the Kentmere valley at Staveley Mine, near Millrigg Knott [NY 463 014], and at Borwick Fold [SD 4422 9694] and at Knipe Tarn. Little is recorded of these workings.

Limestone is the principal source of crushed rock aggregate in Cumbria. Most commercial quarrying of lower Carboniferous rocks of the north-east of the district is from the upper part of the Great Scar Limestone Group; currently there is no active exploitation of units below the Ashfell Limestone. The Knipe Scar Limestone Formation and underlying Potts Beck Limestone are valued as sources of high purity limestone (defined as >97% CaCO₃). Around Kendal, the Park

Limestone Formation is lithologically and geochemically uniform, and capable of producing strong, low porosity limestone aggregates; it is also classed as high purity. Limestone from this formation is currently quarried at Kendal Fell [SD 502 925], to the west of the town.

Though the volcanic rocks in the Lake District are an important resource of crushed rock aggregate and some lithologies produce high specification aggregates, these rocks are not worked in the Kendal district. Of the Silurian strata, greywacke sandstone of the Kirkby Moor Formation is quarried at Roan Edge, near Kendal [SD 585 926], for a range of aggregate uses, including skid resistant road surfacing materials. Shap Granite was formerly worked for roadstone and as a crushed rock aggregate from the Shap Pink Quarry [NY 558 084].

Sand and gravel resources within the district include glaciofluvial and river deposits, confined mainly to the major river valleys of the Kent and Lune. Currently, there is no active working in the district.

Many local rock types have been used as sources of building stone. In the Lake District National Park older buildings are of volcanic rock or, as in Windermere for example, of lithologies from the Windermere Supergroup. Shap Granite has been quarried commercially for at least the last 150 years from Shap Pink Quarry and quantities are still produced intermittently for decorative work. Carboniferous limestone in the district was used in the older parts of Kendal, for example. Today, there is some small-scale quarrying of the Scandal Beck Limestone for building stone around Orton, in the north of the district.

The slate industry has operated in the Lake District for more than 2000 years and today produces two distinct products: the renowned 'Lakeland green slate', from volcaniclastic rocks in the Borrowdale Volcanic Group, and 'blue-grey slate' extracted from cleaved mudstone particularly of the Brathay and Wray Castle formations. Prepared surfaces of the volcaniclastic sandstone, mudstone and tuff from the Borrowdale Volcanic Group display a range of natural colours, grain textures and sedimentary structures, making the green slate much sought after for architectural and ornamental purposes. Extensive disused Lakeland green-slate workings occur in the Kendal district in an east-north-east-trending belt from Troutbeck to Kentmere, Wren Gill and Mosedale [SD 427 062]–[SD 494 097], and a substantial resource remains in this area. Workings are largely within the Woundale and Seathwaite Fell formations. Blue-grey slate appears not to have been exploited in the Kendal district.

During the twentieth century, the only economically viable diatomaceous earth or diatomite deposit in England was located in the Kentmere valley, to the south of the village of Kentmere. There, over an area of about 30 hectares, alluvium of the River Kent is underlain by a deposit of diatomite that is mostly more than 4.5 m thick, and in the west of the basin up to a maximum of about 11.5 m. The deposit consists of about 20 per cent intact siliceous exoskeletons of diatoms (unicellular algae) and up to 40 per cent algal fragments, making it unsuitable for the material's commercially important use as a filter. Rather, it was used mainly for the manufacture of insulation materials and other calcium silicate products. The Kentmere deposit was worked only from 1924 until 1975, with production up to 3500 tonnes per year. A further small deposit, of about 14 000 tonnes, occurs east of Kentmere, at Skeggles Water [NY 480 033].

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 above-average content of the radioactive elements uranium, thorium and potassium (Lee et al., 1987). Measurements in boreholes sunk into the Shap Pluton 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

The average annual rainfall in the Kendal district is about 2000 mm, but local variation closely reflects the topographical relief, with averages ranging from 2800 mm on the high ground around Harter Fell and High Street in the north-west, to 1300 mm to the south of Kendal, and 1400 mm in the Lune valley and around Sedbergh. The average evapotranspiration rates are about 470 mm/yr. The annual infiltration rate in the district is estimated at less than 40 mm (C K Patrick, in Moseley, 1978), but locally, where rocks are more permeable, this may be greater.

Of the 187 records for the district in the National Well Archive, 114 are spring supplies which have been exploited (although very many more are present), 52 are shallow wells (or well fields) and only 21 are boreholes deeper than 10 m. Surface and groundwater abstractions in the district range from small volumes for domestic and agricultural use, to large volumes for industrial purposes such as paper manufacturing. The annual total of licensed water abstractions in the district equates to approximately 44 Ml/d, less than 5 per cent of which is from boreholes and wells, while the remainder is derived in approximately equal proportions from reservoirs, including surface catch pits, and from rivers.

Significant aquifers are not hosted by Borrowdale Volcanic Group and Windermere Supergroup rocks, though these rocks can provide private supplies of the order of 1 l/s, developed either from the numerous springs that issue from lithological or structural boundaries, or from the shallow, fractured and weathered zone. The quality of this groundwater is typically good, with a low content of total dissolved solids.

The Great Scar Limestone and Ravenstonedale groups may contain useful minor aquifers. Limestone and any sandstone bodies present are generally water bearing, whereas interbedded mudstones typically act as confining beds. The limestone matrix has low porosity and permeability, and so will only form an aquifer where fractures are present and particularly where these have been enhanced by dissolution; karstic conditions have developed in extreme cases. Groundwater levels and yields from boreholes in these fractured systems are variable and unpredictable. Quality is typically good, but harder and with a greater content of total dissolved solids. Where fracture flow dominates, groundwater is more vulnerable to contamination from surface pollution.

Thick permeable gravel deposits within the superficial deposits act as minor aquifers which, as well as providing baseflow to watercourses, are exploited for industrial purposes, for example around Mintsfeet in Kendal. Sand and gravel lenses in hillside till and peat are other potential sources of groundwater from springs. Water quality from these sources will be similar to those described above, but are sometimes more mineralised than that of associated surface waters. The till sheets may significantly restrict recharge into parts of the underlying bedrock, particularly where thick and rich in clay.

At Shap Wells [NY 578 097] in the north of the district, a notable spa well emerges alongside Birk Beck where rocks of the Borrowdale Volcanic Group are overlain by the Shap Conglomerate.

Foundation conditions

Geotechnical data from the district are for major road schemes such as the Kendal Western Bypass, the Barrow Link Main and the Tebay to Thrimby section of the M6 motorway. Other sources include building and bridge development in Kendal. Most data characterise Quaternary deposits. Engineering rock descriptions are typically from within a few metres of rock head, though rocks of the Brathay and Coldwell formations, and Coniston Group are described in the Borrow Beck water tunnel and reservoir investigation.

Foundation conditions on strong rock are generally good, but weathered rock may be weak and closely fissured, particularly if faulted, resulting in variable foundation conditions. Strength, faulting, jointing and weathering are the main controls on engineering behaviour, but metamorphism and the presence of mineral veins, particularly hematite, also weaken the rock mass. Zones with a greater density of faults and joints are typically weathered more deeply than those with fewer fractures. In the Borrow Beck investigation, poor quality rock was encountered within fault zones up to several metres wide.

Engineering problems associated with karst in the Carboniferous limestones include dolines, undulating rock head, clay-filled joints, voids and caverns, and variable foundation conditions. Dolines are abundant on all the limestone outcrops, including where these lie beneath a thin cover of superficial deposits; they typically vary in diameter from 5 to 20 m, with depths up to 7 m. Doline collapses have affected farms and buildings, and larger collapse depressions are especially concentrated along the Breakyneck Scar Limestone Formation. Limestone pavement was found beneath Quaternary cover in boreholes for the Kendal Western Bypass (A591). Site investigation, particularly for foundations, must involve a careful search for voids and poor quality rock. Boreholes may not provide sufficient information of the distribution of good rock, poor quality rock and voids. In these cases, geophysical methods may be used to identify near surface structures and more competent rock.

Foundation conditions on the superficial deposits are mixed because of the variable thickness, lithology and geotechnical properties of the various units. Dense, granular alluvium, river terraces, glaciofluvial sands and gravel, and alluvial fan deposits provide generally good foundation conditions. However, poor foundation conditions are found in the loose sands and gravels, and uncompacted silt and firm clay, especially below the water table. Care is required during site investigation to identify fine-grained and loose deposits that may occur below dense glaciofluvial sand and gravel, or alluvial deposits. Differential settlement may occur in large buildings founded on materials of different density or different compressibility such as dense coarse material and firm fine-grained material. The high water table in alluvial deposits tends to aggravate this situation. Cable percussion drilling may produce blowing conditions in saturated silty sand if the water balance is not maintained and this may reduce the relative density values in situ. Peat and organic soils generally provide poor foundation conditions, and building on these materials requires specialised foundations.

Till in the district generally provides good foundation conditions, though the uppermost weathered zone may be soft. Problems may arise in construction because the proportion, strength, and size of cobbles and boulders make undisturbed sampling very difficult, and impede driving-in of casing in deeper investigations; resilience against compaction may be shown by low plasticity till as its behaviour may change with small alterations in moisture content. Unpredictable groundwater conditions may arise from lenses of sand and gravel within till.

Man-made deposits are likely to have good foundation conditions on suitably engineered made ground. However, the highly variable character of tipped or dumped domestic and industrial waste makes it unsuitable for most foundations. The greatest hazard in mixed man-made deposits arises if this contains hollow objects and organic waste, which produces methane and carbon dioxide, and is prone to large and variable settlement.

Slope stability

A small number of landslides were recorded in the Kendal district during the resurvey. A rock failure 450 by 600 m has occurred in the Borrowdale Volcanic Group on the steep east-facing slope in Longsleddale; a small gully and back scarp is present and there are several arcuate tension cracks, some of which are open. Minor landslides occur along the springline at the foot of the scarp formed by the upper part of the Stone Gill Limestone west of Chapel Beck [NY 6073 0725] to [NY 6178 0673]. Minor landslides have affected till on some valley sides, notably below Kelleth Rigg [NY 660 050] and near Cunswick Hall [SD 485 934]. Other landslides occur in till below 300 m OD, originally activated by solifluction. These have developed on relatively shallow slopes (< 100). Small, shallow landslides are frequently the result of oversteepening by stream erosion.

Seismicity

Minor seismic events arising from natural earthquakes are not uncommon in north-west England (Musson, 1994). Though there are no grounds for regarding the Kendal 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 Natural England (formerly 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 approximately 30 SSSI in the Kendal district. The Great Asby Scar National Nature Reserve of some 307 hectares, includes some of the best examples of limestone pavement in Britain and is noted for its flora.

Information sources

Geological information held by BGS relevant to the Kendal district is listed below. Enquiries concerning geological data for the district should be addressed to the National Geoscience Information Service, BGS, Edinburgh. The current BGS Catalogue of Geological Maps and Books is available on request and at the BGS website (www.bgs.ac.uk). BGS maps, memoirs, books, and reports relevant to the district may be consulted at BGS and some other libraries. They may be purchased from the BGS Sales Desk, or via the bookshop on the BGS website.

Searches of indexes to some of the materials and documentary records collections can be made on the BGS website.

Geological enquiries, including requests for geological reports on specific sites, should be addressed to the BGS Enquiry Service at Keyworth.

Maps

Geological maps

1:10 000 and 1:10 560

The maps at six-inch or 1:10 000 scale covering all or part of 1:50 000 geological Sheet 39 Kendal are listed below, along with the surveyors' initials and dates of survey. The surveyors were: B Beddoe-Stephens, I C Burgess, E W Johnson, D J D Lawrence, M McCormac, D Millward, J Pattison, R B Rickards, N J Soper, P Stone, B C Webb, N H Woodcock and B Young. The maps are not published, but are available for public consultation in BGS libraries. Uncoloured copies are available for purchase from BGS sales desks. The earlier maps are available for public reference at the BGS Library, Edinburgh.

Note — The Technical and Research reports listed above, including biostratigraphical reports, may be consulted at BGS Libraries or purchased from the BGS Sales Desk.

Digital geological map data

The 1:10 000- and 1:50000-scale BGS maps of the Kendal district 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. Details are given on the BGS website.

Geochemical atlas

Lake District and adjacent areas (1992)

Geophysical maps

1:625000

Gravity anomaly map, UK North (2007)

Magnetic anomaly map, UK North (2007)

Geophysical interpretations on CD

Kimbell, G S, Carruthers, R M, Walker, A S D, and Williamson, J P. 2006. Regional Geophysics of Southern Scotland and Northern England. Version 1.0 on CD-ROM. (Keyworth, Nottingham: British Geological Survey.)

Hydrogeological maps

1:100000

Groundwater vulnerability of south-west Cumbria (Sheet 6) (1990)

Groundwater vulnerability of the Yorkshire dales (Sheet 7) (1990)

Books and reports

British Regional Geology Guides

Northern England, Fifth edition, 2010

Memoirs

Aveline, W T, and Hughes, T Mck. 1872. The geology of the country around Kendal, Sedbergh, Bowness and Tebay. Memoir of the Geological Survey of Great Britain, Quarter Sheet 98NE.

Aveline, W T, and Hughes, T Mck. 1888. Geology of the country around Kendal, Sedbergh, Bowness and Tebay. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 39. Second Edition revised by StracHaN, a.

Popular geology

A 1:200 000 scale full colour satellite image poster, a Holiday Geology Map Guide (Lake District) (1997,) and a Holiday Geology Guide (The Lake District Story) (1999).

Documentary records collections

Collections of records of borehole and site investigations relevant to the district, are available for consultation at the BGS, Edinburgh, where copies of most records can be purchased. BGS also maintains a mining and quarrying dataset.

Hydrogeological data

Records of water wells, springs, and aquifer properties held at BGS Wallingford can be consulted through the BGS Hydrogeology Enquiry Service.

Geophysical data

These data are held digitally in the National Gravity Databank and the National Aeromagnetic Databank at BGS Keyworth.

BGS Lexicon of named rock units Definitions of the stratigraphic units shown on BGS maps, including those named on

Sheet 39 (Kendal), are held in the BGS Stratigraphic Lexicon database, which can be consulted on the BGS website.

BGS Photographs

The photographs used in this Sheet Explanation are part of the National Archive of Geological Photographs, held at BGS in Keyworth and Edinburgh.

Materials collections

Information on the collections of rock samples, thin sections, borehole samples (including core) and fossil material can be obtained from the Chief Curator, BGS Keyworth. Indexes can be consulted on the BGS website.

References

The geological literature about the district is extensive and many of the references cited in the text provide further links to this. 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

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

Capewell, G C. 1955. The post-Silurian pre-marine Carboniferous sedimentary rocks of the eastern side of the English Lake District. Quarterly Journal of the Geological Society of London, Vol. 111, 23–46.

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

Goodchild, J G. 1875. The glacial phenomena of the Eden Valley and the Yorkshire Dale district. Quarterly Journal of the Geological Society of London, Vol. 31, 55–99.

Harker, A, and Marr, J E. 1893. Supple-mentary notes on the metamorphic rocks around the Shap Granite. Quarterly Journal of the Geological Society of London, Vol. 49, 359–371.

Harvey, A M. 1985. The river systems of North-west England. 122–142 in The geomorphology of north-west England. Johnson, R H (editor). (Manchester: Manchester University Press.)

Hirons, S R, and Roberts, B. 1999. Metamorphic survey of 1:50 000 Kendal and Kirkby Lonsdale geological sheets 39 and 49. British Geological Survey Technical Report, WA/99/51.

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.

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.

Ingham, J K. 1966. The Ordovician rocks in the Cautley and Dent districts of Westmorland and Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 35, 455–505.

Kimbell, G S, and Quirk, D G. 1999. Crustal magnetic structure of the Irish Sea region: evidence for a major basement boundary beneath the Isle of Man. 227–238 in In sight of the suture: the geology of the Isle of Man in its Iapetus Ocean context. Woodcock, N H, Quirk, D G, Fitches, W R, and Barnes, R P (editors). Special Publication of the Geological Society of London, No. 160.

King, L M. 1994. Turbidite to stormtransition in a migrating foreland basin: the Kendal Group (Upper Silurian), northwest England. Geological Magazine, Vol. 131, 255–267.

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.

Lawrence, D J D, Webb, B C, Young, B, and White, D E. 1986. The geology of the late Ordovician and Silurian rocks (Windermere Group) in the area around Kentmere and Crook. British Geological Survey Report, Vol. 18, No. 5.

Lee, M K. 1986. A new gravity survey of the Lake District and three-dimensional model of the granite batholith. Journal of the Geological Society of London, Vol. 143, 425–435.

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.

Lee, M K, Brown, G C, Webb, P C,Wheildon, J, and Rollin, K E. 1987. Heat flow, heat production and thermo-tectonic setting in mainland U K. Journal of the Geological Society of London, Vol. 144, 35–42.

Leeder, M R. 1982. Upper Palaeozoic basins of the British Isles — Caledonian inheritance versus Hercynian plate marginal processes. Journal of the Geological Society of London, Vol. 139, 479–491.

Macdonald, R, Thorpe, R S, Gasgarth, J W, and Grindrod, A R. 1985. Multicomponent origin of Caledonian lamprophyres of northern England. Mineralogical Magazine, Vol. 49, 485–494.

McNamara, K J. 1979. The age, stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District. Geological Journal, Vol. 14, 41–68.

Manley, G. 1959. The late-glacial climate of north-west England. Liverpool and Manchester Geological Journal, Vol. 2, 188–215.

Millward, D. 2002. Early Palaeozoic magmatism in the English Lake District. Proceedings of the Yorkshire Geological Society, Vol. 54, 65–93.

Millward, D. 2004a. The Caradoc volcanoes of the English Lake District. Proceedings of the Yorkshire Geological Society, Vol. 55, 73–105.

Millward, D. 2004b. A stratigraphical framework for the Upper Ordovician and Lower Devonian volcanic and intrusive rocks in the English Lake District and adjacent areas. British Geological Survey Research Report, RR/01/07.

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

Moseley, F. 1968. Joints and other structures in the Silurian rocks of the southern Shap fells, Westmorland. Geological Journal, Vol. 6, 79–96.

Moseley, F (editor). 1978. The Geology of the Lake District. Occasional Publication of the Yorkshire Geological Society, No. 3.

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

Nixon, P H, Rex, D C, and Condliffe, E. 1984. A note on the age and petrogenesis of lamprophyre dykes of the Cautley area, Yorkshire Dales National Park. Transactions of the Leeds Geological Association, Vol. 10, 40–45.

Rickards, R B. 1970. The age of the Middle Coldwell Beds. Proceedings of the Geological Society of London, No. 1663, 111–114.

Rickards, R B, and Woodcock, N H. 2005. Stratigraphical revision of the Windermere Supergroup (Late Ordovician–Silurian) in the southern Howgill Fells, N W England. Proceedings of the Yorkshire Geological Society, Vol. 55, 263–285.

Selby, D, Conliffe, J, Crowley, Q G, and Feely, M. 2008. Geochronology (Re-Os and U-Pb) and fluid inclusion studies of molybdenite mineralisation associated with the Shap, Skiddaw and Weardale granites, U K. Applied Earth Science, Vol. 117, 11–28.

Shaw, R W L. 1971. The faunal stratigraphy of the Kirkby Moor Flags of the type area near Kendal, Westmorland. Geological Journal, Vol. 7, 359–380.

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.

Soper, N J, and Woodcock, N H. 2003. The lost Lower Old Red Sandstone of England and Wales: a record of post-Iapetan flexure or Early Devonian transtension? Geological Magazine, Vol. 140, 627–647.

Soper, N J, Webb, B C, and Woodcock, N H. 1987. Late Caledonian (Acadian) transpression in north-west England: timing, geometry and geotectonic significance. Proceedings of the Yorkshire Geological Society, Vol. 46, 175–192.

Stanley, C J, and Vaughan, D J. 1982. Copper, lead, zinc and cobalt mineral-ization in the English Lake District: classification, conditions of formation and genesis. Journal of the Geological Society of London, Vol. 139, 569–579.

Stephenson, D, Bevins, R E, Millward, D, Highton, A J, Parsons, I, Stone, P, and Wadsworth, W J. 1999. Caledonian Igneous Rocks of Great Britain. Geological Conservation Review Series, No. 17.

Stone, P, Cooper, A H, and Evans, J A. 1999. The Skiddaw Group (English Lake District) reviewed: early Palaeozoic sedimentation and tectonism at the northern margin of Avalonia. 325–336 in In sight of the suture: the geology of the Isle of Man in its Iapetus Ocean context. Woodcock, N H, Fitches, W R, Quirk D G, and Barnes, R P (editors). Geological Society of London Special Publication, No. 160.

Thomas, G S P. 1999. Northern England. 91–98 in A revised correlation of the Quaternary deposits in the British Isles. Bowen, D Q (editor). Special Report of the Geological Society of London, No. 23.

Wells, S G, and Harvey, A M. 1987. Sedimentologic and geomorphic variations in storm-generated alluvial fans, Howgill Fells, north-west England. Geological Society of America Bulletin, Vol. 98, 182–198.

Wilson, A A, and Cornwell, J D. 1982. The Institute of Geological Sciences borehole at Beckermonds Scar, north Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 44, 59–88.

Woodcock, N H, and Rickards, B. 2003. Transpressive duplex and flower structure: Dent Fault System, N W England. Journal of Structural Geology, Vol. 25, 1981–1992.

Young, B, and 8 others. 2001. Mineral resource information for Development Plans: Phase One Cumbria and the Lake District (Cumbria, Lake District National Park and part of Yorkshire Dales National Park). British Geological Survey Technical Report, WF/01/02.

Index to the 1:50 000 Series maps of the British Geological Survey

The map below shows the sheet boundaries and numbers of the 1:50 000 Series geological maps. The maps are numbered in three sequences, covering England and Wales, Northern Ireland, and Scotland.The west and east halves of most Scottish 1:50 000 maps are published separately. Almost all BGS maps are available flat or folded and cased.

(Index map)

The area described in this sheet explanation is indicated by a solid block.

British geological maps can be obtained from sales desks in the Survey's principal offices, through the BGS London Information Office at the Natural History Museum, and from BGS-approved stockists and agents.

Figures and plates

Figures

(Figure 1)a Bouguer gravity anomalies contoured at 1 mGal intervals. Anomalies calculated against the Geodetic Reference System 1967 using a variable reduction density and referred to the National Gravity Reference Net 1973. Geophysical lineament after Lee (1989). b Total magnetic field contours at 10 nT intervals. Anomalies referred to a variant of IGRF90. Geophysical lineament after Lee (1989).

(Figure 2) Details of the formations in the Borrowdale Volcanic Group in the Kendal district.

(Figure 3) Details of formations in the Dent Group in the Kendal area.

(Figure 4) Details of the Silurian strata within the Windemere Supergroup.

(Figure 5) Lithostratigraphical variation within the Silurian part of the Windermere Supergroup (after Rickards and Woodcock, 2005).

(Figure 6) Devonian and Carboniferous rocks of the north-east of the district.

(Figure 7) Details of the Carboniferous rocks of the area around Kendal.

(Figure 8) Details of intrusive rocks in the Kendal district.

(Figure 9) Mineralisation and summary of mining history in the Kendal district.

Plates

(Plate 1) Langdale Fell and the northern part of the Howgill Fells, seen from the north. The upland fells, underlain by sandstone of the Coniston Group, contrast with the undulating till-covered centre and foreground (P668821).

(Plate 2) Transverse, branched ripples developed in the muddy siltstone division of a turbiditic sandstone sequence, Poolscar Formation (Coniston Group). Allen Knott Quarry [NY 4149 0110], Troutbeck (P223337). The hammer is 37 cm long.

(Plate 3) Calcareous mudstone and siltstone with interbedded (brown-weathered) nodular limestone, dipping to the right in the Dent Group at Moor Head, Troutbeck [NY 4243 0365]. A near vertical cleavage can be seen in the mudstone units (P223319). The hammer is 37 cm long.

(Plate 4) Scandal Beck Limestone showing characteristic intercalated thick- and thin-bedded limestone, Raisbeck Quarry [NY 6490 0690], near Orton (P223193). The quarry face is approximately 10 m high.

(Plate 5) Glaciated Kentmere valley, just north of Kentmere village, with rock-cored mounds of till, and (right of centre) alluvial deposits of a late-glacial lake. Borrowdale Volcanic Group rocks are seen in the background (P668866).

(Plate 6) Major arterial road and rail routes linking the north and south of Britain routed through the Lune gorge (P668922).

(Front cover) Longsleddale. Borrowdale Volcanic Group rocks of Goat Scar with glacial and fluvial deposits alongside the River Sprint. (Photographer F I MacTaggart; P668841).

(Rear cover)

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

(Index map) Index to the 1:50 000 Series maps of the British Geological Survey.

Figures

(Figure 3) Details of formations in the Dent Group in the Kendal area

(Figure 4) Details of the Silurian strata within the Windemere Supergroup

(Figure 6) Details of formations in the Dent Group in the Kendal area

(Figure 7) Details of the Carboniferous rocks of the area around Kendal

(Figure 8) Details of intrusive rocks in the Kendal district

(Figure 9) Mineralisation and summary of mining history in the Kendal district