Geology of the Barnsley district — a brief explanation of the geological map Sheet 87 Barnsley

E Hough, R D Lake, and P R N Hobbs

Bibliographic reference: Hough, E, Lake R D, and P R N Hobbs. 2007 Geology of the Barnsley district — a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 87 Barnsley (England and Wales).

Keyworth, Nottingham: British Geological Survey, 2007. Printed in the UK for the British Geological Survey by B&B Press Ltd, Rotherham.

© NERC 2007 All rights reserved. Copyright in materials derived from the British Geological Survey's work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, e-mail ipr@bgs.ac.uk. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract.

(Front cover) Wharncliffe Crags [SK 297 975] (a Geological SSSI) are formed by two sandstone beds that together comprise the Wharncliffe Rock, from the Pennine Lower Coal Measures Formation. The sandstone beds preserve an excellent example of a fluvial meander belt, with cross-bedding indicating lateral accretion on a point-bar, and soft-sediment deformation structures. The coarse grain size of parts of the Wharncliffe Rock made it well-suited to the manufacture of querns, small stones used to grind cereals, which were made in this area during Iron Age to Roman times. (Photograph P Witney; P662704).

(Rear cover)

Notes

The word 'district' refers to the area of Sheet 87 Barnsley. National Grid references are given in square brackets; all lie within the 100 km squares SE and SK; the latter are prefixed accordingly. Borehole records referred to in the text are prefixed by the code of the National Grid 25 km² sheet upon which the site falls, for example SK49SE. Photographs are from BGS archive, registration numbers are given in captions.

Acknowledgements

This Sheet Explanation was written by E Hough and R D Lake; P R N Hobbs wrote much of the section on Applied Geology.

We acknowledge the assistance provided by the Coal Authority, Environment Agency, and numerous civil engineering consultants. Landowners, tenants and quarry companies are thanked for permitting access to their lands.

Cartography was done by R J Demaine; pagesetting by A Hill.

The grid, where it is used in figures, is the National Grid taken from Ordnance Survey mapping. Ordnance Survey licence No. 100017897/2007.

Geology of the Barnsley district (summary from rear cover)

(Rear cover)

(Geological succession) Geological succession in the Barnsley district.

An explanation of sheet 87 (England and Wales) 1:50 000 series map

The geology described in this Sheet Explanation includes the Carboniferous Millstone Grit Group, which was deposited in deltaic systems at the mouth of a large river system flowing from the north. Initially the river discharged its load into a deep basin, which over time filled with sediment and the distributaries then flowed across a gently sloping delta plain on which mire-swamps and freshwater lakes developed. It was in these environments that the Pennine Coal Measures Group, including the economically important seams of coal, was deposited. The Permian strata show that there was a transition from aeolian (Rotliegendes Group) to marine conditions (Zechstein Group — mudstone and limestone). The Triassic Sherwood Sandstone Group is the youngest bedrock here, comprising sandstones of both fluvial and aeolian origin.

The landscape, to a great extent, reflects the underlying geology. Upland moors in the south-west are underlain by the Millstone Grit Group. Broad, gently undulating agricultural land in the east is underlain by Permo-Triassic rocks.

The intervening tract of land is characterised by classic 'dip and scarp' scenery, developed on interbedded sandstone and mudstone units of the Pennine Coal Measures Group. Glacial and postglacial deposits underlie flat-lying ground in the north and east of the district. Within the past 10 000 years, modern rivers have deposited broad tracts of alluvium, and landslides have developed on the steeper slopes of the Millstone Grit.

For hundreds of years, geology has played a significant part in the social and economic development of the Barnsley district; sandstone, mudstone, sand and limestone have been exploited as mineral resources. However, it is coal that has had the greatest impact on the area — the coal industry was the major employer for much of the 18th to late 20th centuries in South Yorkshire, and many pit villages and towns sprang up to provide accommodation for miners. The coal industry has left a legacy of challenging ground conditions including large areas of colliery spoil and infilled ground, which must be treated appropriately when redevelopment takes place.

Chpter 1 Introduction

This Sheet Explanation provides a summary of the geology of the district covered by the geological 1:50 000 Series Sheet 87 Barnsley published as a bedrock and superficial edition in 2007. Further detail is available in the Sheet Memoir (1947), reprinted in 1954 (Mitchell et al., 1954). Information specifically regarding the Pennine Lower and Middle Coal Measures formations of the Barnsley district is given in Lake (2006). The district lies predominantly in the county of South Yorkshire, principally in the Barnsley, Rotherham and Doncaster Metropolitan Boroughs. It also includes small areas of Kirklees Metropolitan Borough in the north-west and Sheffield Metropolitan Borough in the south-east. The northern part of the district lies within the county of West Yorkshire. The main population centres are Barnsley, and the northern outskirts of Rotherham. Smaller towns include Royston, Hoyland, Stocksbridge, Ardwick le Street and the conurbation of Wath-Upon-Dearne, Swinton, Mexborough and Conisbrough. These towns are separated by areas of farmland and scattered villages; small areas of moorland are present in the south-western part of the district. The district is drained by the rivers Don and Dearne, and Hampole Dike, which eventually join the Ouse at Goole, to the north-east of the district. The coat-of-arms for Barnsley shows a coal miner and glass blower, representing two industries intimately linked to the underlying geology that defined the area's industrial development. Although glass making is still a major employer, the decline of the coal industry, which employed over 15 000 in the district during the early 1980s, was complete in 1994 with the closure of Goldthorpe Colliery.

The bedrock (Figure 1) is composed of sedimentary rocks that were deposited during the Carboniferous, Permian and Triassic periods, a time span of between 354 and 241 Ma. The oldest strata proved in the Barnsley district are of the Namurian (Carboniferous) Millstone Grit Group, comprising interbedded mudstone and pebbly sandstone. The Millstone Grit Group is overlain by the Pennine Coal Measures Group, which was deposited in a complex of fluvial, lacustrine and swamp environments. The Group is dominated by grey mudstone with subordinate beds of sandstone and coal. Marine bands, deposited at times of relatively high sea-level, are preserved throughout the succession, allowing for the development of a detailed chronostratigraphy. The Pennine Coal Measures Group gives rise to a classic dip-and-scarp scenery, in which thicker sandstone units such as the Grenoside Sandstone and Oaks Rock form steep south-west-facing escarpments, with broad gentle dip slopes to the north-east.

Permo-Triassic strata crop out in the eastern part of the district. The western limit is typically marked by a major escarpment; to the east of this, the topography is a gently undulating plateau. The Permian strata consist of reworked aeolian deposits (Yellow Sands Formation) that are followed by the cyclical deposition of dolomitic limestones formed during marine transgressions (the Cadeby and Brotherton formations) and red mudstones deposited during partial marine regressions (the Edlington and Roxby formations). The youngest bedrock strata preserved in the district are red-brown sandstones of the Sherwood Sandstone Group, deposited in a mixed fluvial-aeolian regime.

During the Quaternary Period, unconsolidated material including Till and Glaciofluvial Deposits were deposited by a thick ice-sheet possibly of mid-Pleistocene (Anglian) age. Younger unconsolidated deposits, including lacustrine sands, silts and clays, accumulated on the floor of 'Lake Humber' during the Late Devensian stage. Subsequently, in Holocene times, Alluvium and River Terrace Deposits were laid down by the larger stream and river systems of the modern landscape.

Chapter 2 Geological description

Palaeozoic and Lower Carboniferous (Tournaisian to Visean)

Knowledge of Visean and older strata comes from interpretations of seismic reflection data, originally acquired by oil exploration companies in the 1980s. The oldest strata interpreted are undivided Lower Palaeozoic rocks, which are in excess of 2000 m thick in the south-western part of the district. During this time, deposition was active in the Alport Basin in the south-western part of the district, and the Huddersfield Basin–Gainsborough Trough on the northern fringe of the district; the Holme High may have had an influence on deposition in the central and western parts of the district. Up to approximately 2750 m of Tournaisian and Visean strata has been identified beneath Namurian rocks in the district. Based on regional paleogeographical models (Kirby et al., 2000), Tournaisian and Visean rocks are thought to comprise deep water facies developed in dominantly basinal environments.

Pennsylvanian (Late Carboniferous)

Carboniferous rocks are present at surface in the central and western parts of the district. To the east they pass beneath younger strata, and for this concealed part of the Carboniferous sequence, correlations between the Warmsworth Borehole (SE50SW/64) [SE 539 012] and other oil exploration boreholes beyond the eastern margin of the district are given in Gaunt (1994). Seismic reflection data suggest that the total thickness of Namurian strata in the district is about 1000 m, of which the stratigraphically highest 190 m are exposed at outcrop, with a further 95 m known from borehole provings. In excess of 1500 m of Westphalian rocks from the Pennine Coal Measures Group are preserved in the district.

Namurian strata belong to the Millstone Grit Group (MG), a lithostratigraphical unit comprising interbedded mudstone and sandstone. The outcrop of the Millstone Grit is restricted to the south-western part of the district, where it forms moorland around Ewden Village [SK 273 962] and Wharncliffe Side [SK 298 950]. Millstone Grit has also been proved by the South Kirkby (SE41SE/59) [SE 455 109] and Warmsworth oil exploration boreholes, located in the north and east of the district respectively.

During the Namurian epoch, approximately 320 million years ago, northern England lay within a large, actively subsiding basin connected to the sea. Rivers draining from landmasses to the north carried sediments that were deposited within extensive deltas which expanded outwards into the basin. The coarser grained sediments were deposited in fluvial channels, levees, deltas and submarine fans, and were eventually lithified as sandstone, whereas silt and clay, which settled in areas of standing water or in offshore marine environments, are now preserved as beds of mudstone.

The Millstone Grit succession in the Pennine region was laid down in sedimentary cycles (cyclothems), which are now generally believed to have resulted from sedimentation during cyclical glacioeustatic variations in sea level, superimposed on progressive subsidence of the basin (Leeder, 1988). Each cycle begins with a deposit of mudstone, near the base of which are beds containing marine faunas, inferred to have been deposited at times of high global sea-level. Each marine band (Figure 2), typically a few centimetres thick, generally contains a distinctive and diagnostic faunal assemblage. They can be recognised regionally, and are important marker horizons. The marine mudstones commonly pass up into unfossiliferous mudstone, and then into sandstone, each upward-coarsening unit representing an advance of the delta. The sandstone units, many of which are named, are generally similar to one another in their petrographical and sedimentological features, and are mainly distinguished by their position relative to the marine bands described above. Pelagic environments were therefore replaced by delta slopes, and finally by sandfilled distributary channels of the delta top. The delta top environments were colonised by plants, especially during times of lowered sea level, leading to the development of soils and deposits of peat. Once subjected to lithification, the soil horizons became seatearth and the peats compacted to coal. This pattern of deposition was repeated with each rise and fall in sea level.

Depositional models have been provided by McCabe (1978) and Hampson (1997) for the Kinderscoutian part of the succession, by Wignall and Maynard (1996) and Brettle (2001) for the early Marsdenian, and by Bristow (1988) and Hampson et al. (1996) for the Yeadonian. Collinson (1988) has reviewed the sedimentation of the Millstone Grit as a whole.

The sandstone nomenclature in this account is broadly the same as that used during the previous survey, although some names have been changed to conform to those used in the adjoining Huddersfield district (Addison et al., 2003). Some terms, such as 'grit' and 'rock', are maintained for sandstone units with names that are already well established in the literature; 'grit', 'rock' and 'sandstone' are considered synonymous in the following text.

The Namurian Epoch is divided into seven stages, which are in turn subdivided into chronozones (Ramsbottom et al., 1978). The boundaries of these chronostratigraphical subdivisions are recognised by the presence of age-diagnostic ammonoid (goniatite) faunas. The three highest stages, the Kinderscoutian, Marsdenian and Yeadonian, have been identified in the district (Figure 2).

Kinderscoutian strata are not exposed at rockhead, but their existence is confirmed by provings from deep boreholes in the north and east of the district. In the Warmsworth Borehole [SE 539 012] (Figure 3), these strata comprise 24 m of medium-grained sandstone with variable carbonate cement, and subordinate beds of mudstone. The geophysical log for the South Kirkby Borehole [SE 455 109] shows 10 m of strata characterised by a serrated gamma-ray response (Whittaker et al. 1985). Rock chippings from the borehole indicate the interval comprises fine- to medium-grained, micaceous sandstone interbedded with dark grey sandy siltstone.

Marsdenian strata comprise interbedded sandstone and mudstone, with a total thickness proved in the district of approximately 195 m. Strata above the Bilinguites metabilinguis Marine Band are present at outcrop; below this the sequence is known only from borehole log data. The Bilinguites gracilis Marine Band (R_2a1), which marks the base of Marsdenian strata, is typically underlain by 2 to 3 m of micaceous silty mudstone. The marine band comprises dark grey, finely laminated mudstone with the diagnostic ammonoid B. gracilis, and with Dunbarella and Posidoniella commonly present near the top and base. The Readycon Dean Flags have been tentatively identified as a 5 m-thick interval from the geophysical log of the Warmsworth Borehole [SE 539 012] (Figure 3). It is in turn succeeded by the Midgeley Grit, which is up to 30 m thick above a thin mudstone unit separating it from the Readycon Dean Flags. The Bilinguites metabilinguis Marine Band (R_2b5) lies just above the Midgeley Grit and forms the base of a 25 m thick mudstone sequence. The Guiseley Grit (G), which is fine grained and micaceous, was formerly referred to as the 'Beacon Hill Flags' in the Barnsley district (Mitchell et al., 1947). The overlying sequence, up to the base of the Huddersfield White Rock, is dominated by mudstone with the Bilinguites superbilinguis Marine Band (R_2c1) about 25 m below the base of the Huddersfield White Rock. The Huddersfield White Rock (WR), 12 to 18 m thick, is a fine- to medium-grained, micaceous sandstone that shows thin planar bedding and common ripple cross-lamination; its upper part is typically ganisteroid. These sedimentological features indicate deposition on a fluvial tributary mouth-bar. Strata above the Huddersfield White Rock are dominated by mudstone, with two thin sandstone beds. The upper of these corresponds to the Redmires Flags of the Sheffield district, where it is typically a well-bedded coarse-grained, feldspathic sandstone (Eden et al., 1957).

The base of Yeadonian strata is defined at the base of the Cancelloceras cancellatum Marine Band (G_1a1). The Cancelloceras cumbriense Marine Band (G_1b1) occurs some 12 m higher, the strata between the two marine bands being dominantly argillaceous. Mudstones overlying the C. cumbriense Marine Band vary greatly in thickness due in part to downcutting by the base of the Rough Rock. The Rough Rock (RR) is the youngest sandstone of the Millstone Grit Group. It comprises medium to very coarse-grained, massive or cross-bedded feldspathic sandstone, commonly with granules and small rounded pebbles predominantly of quartz. The total thickness of Rough Rock is estimated to be about 10 to 20 m in the Stocksbridge area [SK 270 980], and boreholes around Thurgoland [SE 280 010] record up to 29 m of sandstone. Regional controls on the sedimentation of the Rough Rock are discussed by Bristow (1988), who refers to this sandstone as a widespread, multi-storey and multi-lateral fluvial sheet sandstone with a sharp, slightly channelled erosion surface at the base. It is interpreted as the deposit of a braided river, which, based on palaeocurrent information, evidently flowed towards the south. The Pot Clay and Pot Clay Coal overlie the Rough Rock. In boreholes around Stocksbridge [SK 270 980], the Pot Clay Coal is 0.35 m thick and rests on 1.3 m of the Pot Clay seatearth, the latter separated from the Rough Rock by 1 m of mudstone.

Key locality

Huddersfield White Rock. Loadfield Quarry [SK 258 949]

Westphalian

The Westphalian Series, represented by the Pennine Coal Measures Group, is divided on the basis of faunal marker horizons into four chronostratigraphical stages, of which the lower three are present in the district (Figure 2) and are delimited by the Subcrenatum, Vanderbeckei and Aegiranum marine bands. These define the respective bases of the Langsettian, Duckmantian and Bolsovian stage boundaries. The Pennine Lower, Pennine Middle and Pennine Upper Coal Measures formations are lithostratigraphical units that take their respective lower boundaries at the bases of the Subcrenatum and Vanderbeckei marine bands and at the top of the Cambriense Marine Band (Stubblefield and Trotter, 1957). The Pennine Coal Measures Group consists of a large number of units characterised by a succession of interbedded grey mudstone, siltstone, sandstone, seatearth, coal and rare ironstone and tonstein. The Pennine Lower Coal Measures Formation (PLCM) is up to 635 m thick, and is present at crop in the south and western parts of the district. The succeeding Pennine Middle Coal Measures Formation (PMCM), which reaches 700 m in the Royston area, forms a broad north-west-trending outcrop in the central part of the district. Each of these formations shows a general trend of thickening to the west or south-west. The Pennine Upper Coal Measures Formation (PUCM) (which reaches 335 m in the Thurnscoe area) occupies the easternmost Westphalian outcrop and is overlain unconformably by Permian strata. The coal seams of the Upper Coal Measures are generally unproductive, being thin or dirty (mud-rich), and occur within a sequence dominated by sandstone.

Two major facies associations have been recognised within the Langsettian and Duckmantian strata of the Pennine Basin, demonstrating deposition in lower delta plain/shallow water delta and upper delta plain environments. The former is characterised by several laterally extensive marine bands, with ganisters being preferentially developed as well-drained, podzolic palaeosols in the same situation (Besly and Fielding, 1989). Thick peat accumulation, which gave rise to economically useful coal seams, was favoured in the upper delta plain environment.

Guion and Fielding (1988) recognised several controls on sedimentation: a large-scale control by major delta switching or marine transgression, a medium-scale effect by a combination of compaction and tectonically induced subsidence, and a small-scale control by local fluviatile and deltaic processes. In the last example, the presence of sandstone bodies may have created contemporaneous topographic highs above which the coals are thinner or sequences may be condensed (Bedrock, 1984; Cochrane, 1991).

Westphalian sandstones (Figure 4); (Plate 1), (Plate 2), (Plate 3), (Plate 4), consist mainly of subangular to subrounded quartz grains, with some feldspar and a minor amount of mica. The grain size is generally very fine to medium, with coarse-grained and pebbly units occurring locally. Most sandstones are grey when fresh, but commonly weather to a yellowish brown sandy soil, which in ploughed fields contains an abundant 'brash' of small sandstone fragments. Where exposed, the bases of many sandstone beds are erosional, indicating downcutting by fluvial channels into older sediment.

Siltstones are typically medium grey with plant debris; extensive details of the fossil plants identified within the Coal Measures of the Barnsley district are given in Mitchell et al. (1947). They grade both vertically and laterally into sandstones and mudstones and are commonly intimately interbedded with both. The sandstones and siltstones relate to a variety of fluviatile environments of deposition including: distributary channels, crevasse splays and channels, overbank flood basins and lacustrine delta fronts. Coarsening-upwards sequences generally indicate deposition within crevasse splays or minor deltas; large-scale examples of this are associated with the delta front environment. The mudstones are generally grey to dark grey, weathering to a stiff to firm, orange-brown, mottled pale grey clay. Nodules of sideritic ironstone are common, ranging in size from a few millimetres up to 0.5 m. Some beds of ironstone have been extensively worked in the past, including the Claywood Ironstone (Pennine Lower Coal Measures Formation) extracted from south-east of Chapeltown [SK 363 961], and the Tankersley Ironstone (Pennine Lower Coal Measures Formation) worked from Tankersley Park [SK 348 988]. Mudstones were deposited in a number of environments including lakes and fluviatile overbank or prodelta areas; they are also interbedded with the coarser lithologies or form part of coarsening-upwards sequences. Some beds contain nonmarine bivalves; extensive Euestheria bands, identified in the Pennine Upper Coal Measures Formation, are shown on component 1:10 000 Series maps covering the eastern part of the Barnsley district.

Marine bands (Figure 2) are beds of dark grey mudstone with a marine fauna including age-diagnostic ammonoids. They generally occur a short distance above a coal or a seatearth, and although normally only a few centimetres thick, some may attain thicknesses in excess of a metre. Marine bands commonly grade upwards into dark grey mudstones with a nonmarine fauna including lamellibranch genera Anthracomya, Anthraconauta, Carbonicola and Naiadites. They are recognised across large areas and are consequently important marker horizons that allow sequences of similar age to be defined and correlated.

Seatearth is the name given to fossil soil profiles (palaeosols) that commonly underlie coal seams. Seatearths may be useful for correlation, particularly where the associated marine band is absent, as they indicate periods of relative emergence. They can be developed in various lithologies, and are recognised as pedogenic features by the presence of fossil rootlets; in general, however, the soil-forming processes have destroyed primary sedimentary structures. Where developed on the tops of sandstone beds, seatearths include compact quartzites, termed 'ganister'; ganister was previously extracted from Parsonage Farm [SK 287 967], probably used as a component of refractory bricks.

Coal seams (Figure 5) are numerous, and many can be traced over much of the eastern part of the Pennine Basin. Lateral variations in seam thickness and composition are chiefly controlled by the number of 'dirt' partings present within the seam horizon. Where these partings are particularly prominent, the separate coals, known as leaves, may be individually named. Seam splits are also common, and individual leaves or entire seams may die out laterally. Differential compaction of strata within palaeovalleys, or across topographic 'highs' is at least in part responsible for local complexities that have resulted in different coals within narrow stratigraphic intervals splitting in opposing directions. A tonstein horizon, comprising a dense, kaolinitic mudstone layer that is about 25 mm thick and pinkish brown in colour, is present around the level of the Sharlston Low Coal (Pennine Middle Coal Measures Formation). This important stratigraphical marker bed was interpreted by Spears and Kanaris-Sotiriou (1979) to have formed from ash fall-out from an acidic volcanic source.

Key localities

• Wharncliffe Rock. Wharncliffe Crags [SK 297 975] (Front cover)
• Greenmoor Rock. Plank Gate rail cutting [SK 297 988]
• Grenoside Sandstone. Finkle Street road cutting [SK 299 989]
• Silkstone Rock. Barnsley Road (A628) cutting [SE 291 056]
• Woolley Edge Rock. Burton Bank Quarries [SE 354 078] (Plate 1)
• Glass Houghton Rock. Cudworth Quarry [SE 382 087] (Plate 2)
• Mexborough Rock. Hemp Dike rail cutting [SE 394 115]
• Ackworth and Brierley members. Frickley Bridge rail cutting [SE 400 117] to [SE 410 119] (Plate 4)

Permian and Triassic

These strata are present in the eastern part of the district, where they 'young' progressively eastwards in response to the prevailing dip. The stratigraphically youngest part of the preserved succession is largely concealed by Quaternary deposits. Smith (1995) describes some of the better exposures of Permian strata in the Barnsley district.

Except for scattered plant debris, the only macrofossils of Permo-Triassic age in the district are the generally sparse Upper Permian marine faunas of the Cadeby and Brotherton formations. This assemblage includes palynomorphs that indicate a late Permian (Kazanian/Tatarian) age (Smith et al., 1974).

In this district, the denuded and weathered top of the Carboniferous sequence is only locally covered unconformably by a friable or weakly cemented sandstone, the Yellow Sands Formation (YwS) (Plate 5) that is up to 5 m thick. This unit, formerly termed the 'Basal Permian Sands', is poorly cemented, pale grey to dark blue-grey, fine- to medium-grained, and contains wind-rounded sand grains, which indicate an aeolian origin, although local pebbles perhaps suggest some fluvial input. Regionally, it passes laterally eastwards into a well-cemented sandy dolostone.

In this district, aeolian sands were probably extensively reworked during the initial transgression of the late Permian shallow epeiric Zechstein Sea, marking the beginning of a series of major and minor cycles of transgression and regression. The Cadeby Formation (CdF), formerly termed the 'Lower Magnesian Limestone', comprises up to 53 m of mainly buff or grey dolostone and dolomitic limestones. It gives rise to a pronounced escarpment along its westernmost outcrop and generally has a sharp base that overlaps the Yellow Sands Formation (Plate 5). A mudstone unit is locally present at the base of the formation; this unit has been proved at depth near Cadeby, to the east of Braithwell, and probably near Bullcroft Colliery, and at the surface in a brickpit [SK 515 981] at Conisbrough, where it is 5 m thick.

Mitchell et al. (1947) made a broad two-fold division of the Cadeby Formation, corresponding approximately with the Wetherby and Sprotbrough members of Smith et al. (1986). However, in the absence of persistent markers and feature-forming beds, the Cadeby Formation is shown as undivided on the map. The lower Wetherby Member comprises well-bedded, granular and ooidal dolostones, together with bioclastic units. A limited molluscan fauna is present, typically in the basal beds of the member, dominated by the bivalve Bakevellia binneyi. Scattered to abundant bryozoan-algal patch reefs occur, particularly near the base. The reefs may be composite in nature and, within the enclosing dominantly ooidal sediments, comprise variously: pale, pillow-shaped masses of unzoned bryozoan dolostone and domed algal stromatolites (Smith, 1981). The former have a brecciated appearance and early authors referred to them as 'breccia' or 'reef-breccia'.

The overlying Sprotbrough Member consists mainly of white or buff, large-scale cross-bedded and parallel-bedded, granular and finely cellular, dolostones which were originally ooidal grainstones. The base of the member is taken at a discontinuity within or below the 'Hampole Beds', originally described by Smith (1968). At the type locality at Hampole [SE 515 097], these beds comprise three clay beds separating dolostones. The lower dolostone is distinctively highly porous, with hollow-cored ooids. Regionally, the base of the Sprotbrough Member is taken at the top of the lower dolostone of the 'Hampole Beds'. Where this is absent, it is taken at the Hampole Discontinuity, at the base of the 'Hampole Beds', which is a locally transgressive, but generally concordant surface.

Near the top of the Sprotbrough Member, interbedded evaporites, anhydrite and gypsum, and mudstones are locally present in borehole sequences; poikilitic gypsum is present throughout the formation. The member contains a sparse fauna of bryozoans, brachiopods and bivalves, although these are not biostratigraphically distinct from that of the Wetherby Member.

The Edlington Formation (EdF) (formerly termed the 'Middle Permian Marl') generally consists of 15 to 45 m of red-brown mudstone ('marl') with sporadic beds of siltstone. Processes of leaching and reduction produce layers and patches that are pale green and grey in colour; in particular the top and bottom beds of the formation are generally leached. Gypsum occurs throughout as beds, layers, nodules, veins and disseminated crystals. Anhydrite occurs at depth, but is hydrated to gypsum near the surface. The extent of dissolution of the evaporites near the outcrop of the Edlington Formation is uncertain, but is probably significant and may account for some component of the observed thickness variations. The formation typically has a sharp lower boundary that is conformable on the underlying Cadeby Formation. The top of the formation is taken below the lowest dolomitic limestone of the Brotherton Formation; it may be gradational locally, with passage beds consisting of alternating mudstone and dolostone.

The Brotherton Formation (Bth) (formerly termed the 'Upper Magnesian Limestone') typically comprises 15 to 18 m of pale grey and cream, thinly bedded, fine-grained dolostones and dolomitic limestones. In the thinly bedded lithologies, contacts between beds are gently undulating, perhaps in response to wave action; grey mudstone partings are locally present. These beds show lamination, with shallow cross-bedding and rippled sets locally developed. This formation is locally subject to intense dissolution effects. It is also much affected by collapse caused by the dissolution of evaporites within the Edlington Formation: the resultant sagging and doming mimics tectonic folding. Fossils are uncommon and restricted to particular beds. They typically include the alga Calcinema permiana and the bivalves Liebea squamosa and Schizodus obscurus.

Formerly termed the 'Upper Permian Marl', the Roxby Formation (RoF) is poorly exposed; it consists of 15 to 20 m of red-brown, gypsum-bearing mudstone that weathers to a heavy red-brown clay. Anhydrite occurs at depth and shows progressive hydration to gypsum, which is abundant in bedded and vein form. The precise position of the boundary between the Permian and Triassic is uncertain, but in eastern England it possibly lies within the highest part of the Roxby Formation (Warrington et al., 1980); the boundary with the overlying Sherwood Sandstone Group is transitional.

The Sherwood Sandstone Group (SSG) has a very restricted crop. Formerly named the 'Bunter Sandstone', it is a brick-red to orange-brown, weakly cemented sandstone, typically of fine- to medium-grain size. Up to 30 m of the group are preserved in fault-bounded grabens on the eastern margin of the district.

Key localities

• Yellow Sands Formation. Watchley Crag, Bilham [SE 475 067] (Plate 5)
• Cadeby Formation. Cadeby Quarry [SE 521 002]; Warmsworth Quarry [SE 537 005]; Glen Quarry [SK 545 947]
• Brotherton Formation. Brodsworth Quarry [SE 526 068]

Superficial (Quaternary) Deposits

During the Quaternary Period, the district was affected by at least two glaciations which produced suites of sediments probably dating from the Anglian and Devensian stages (previously termed the 'Older and Newer Drift'). The deposits of the earlier and more extensive glaciation, which may be of Anglian age, include till and sandy gravel. They are patchily preserved, typically on the higher ground at up to 100 m above OD. In the Dearne Valley near Barnsley and in the easternmost part of the district, however, they occur at lower elevations.

Till, of Anglian age comprises a stiff, brown, sandy clay with varying proportions of pebbles, cobbles and boulders that are mainly of Carboniferous sandstone, but include dolomitic limestones near to or on the Permian crop. Minor amounts of far-travelled 'exotic' clasts also occur, including examples from the Lake District (Mitchell et al., 1947). Where Permian mudstones have contributed to the clay matrix of the deposit, the colour is red-brown. Most occurrences of till are probably thin and degraded but an example, 9 m thick and including laminated clay, was described by Green et al. (1878), near Staincross [SE 346 114]. The feather edges of some of the till deposits are characterised by abundant 'dreikanter' fragments composed of wind-polished siliceous sandstone.

Glaciofluvial Deposits consist of thinly developed sandy gravels with a variable content of silt and clay that are locally associated with till and which are thought to represent contemporary Anglian glacial outwash material. Some of the lower lying isolated outcrops may relate to the later (Devensian) glaciation, but this remains to be confirmed. The clast content is generally dominated by Carboniferous sandstones, but on the Permian crop, dolomitic limestone is abundant.

The genesis and age of some gravelly material and exotic blocks formerly seen near the Hampole Dike [SE 525 102] is uncertain. The relatively low elevations of these deposits may indicate a younger age, but they could be related to a continuation of the Anglian subglacial Arksey Channel of the Doncaster district to the east (Gaunt, 1994). This channel, which contains laminated clays, is concealed beneath the Vale of York Formation, and reaches a depth of 36 m below OD.

The district is thought to lie beyond the limit of the Devensian glaciation, and consequently it does not contain Devensian glacial deposits. During the Devensian, however, ice occupying the present-day Humber-Lincolnshire coastal zone blocked the eastward-draining valleys, including the Humber gap between Brough [SE 940 270] and Winterton [SE 920 180], and thus impounded 'Lake Humber' in the southern part of the Vale of York. The main deposits of this proglacial lake (the Vale of York Formation, formerly termed '25 Foot Drift') are preserved in the north-eastern part of the Barnsley district, forming undulating low ground at about 8 m above OD. Spreads of older sand and gravel thought to be of Ipswichian age flank these sediments at heights of up to 12 m above OD, and are preserved at Skellow [SE 540 102]. To the west of the lake, in the major river valleys, contemporaneous with, and subsequent to this Devensian glacial maximum, glaciofluvial and terrace gravels were deposited which were subject to resorting and are presently patchily preserved.

In this district, gravels that occupy the fluvial channels, but are overlain by Holocene alluvium, are almost certainly composite in origin. It is thought that the earliest preserved deposits relate mainly to the Devensian late glacial maximum and comprise glaciofluvial pebbly sands, interbedded with laminated glaciolacustrine clays, consequent on the impounding downstream of 'Lake Humber'. These early sedimentary infills were subject to later incision and recycling during the formation of the Holocene River Terrace Deposits, and bedrock profiles indicate that the terrace deposits locally overlie distinct benches.

Various occurrences of Lacustrine Shoreface and Beach Deposits flanking the Vale of York and lying at about 30 m above OD were first recognised by Edwards (1937) as strand-line deposits. They are considered to be the remnants of a beach or shoreline marking the limit of glacial 'Lake Humber' during an early high-level phase. These sediments include coarse-grained gravels and cross-bedded sands and silts of local derivation. Ventifacts occur at the base of the deposit and on the surface of the gravels.

The Vale of York Formation comprises Glaciolacustrine Deposits, sand and silt and clay that were deposited in the period before 11 100 ± 200 years BP (Gaunt, et al., 1971). In the central part of the basin to the east and north, the formation is in excess of 20 m thick. In general, clay and silt-rich glaciolacustrine beds are grey-brown or red-brown and are typically parallel-laminated, with thin, fine-grained sand layers that are locally cross-laminated. Glaciolacustrine sand is buff to pale orange and pale grey when fresh; it varies from fine to coarse in grain size, and is in part clayey or silty.

The climatic oscillations during the Quaternary caused significant changes in sea level and consequently, successive phases of fluvial incision and aggradation.

A period of rapid incision in late Devensian times was followed by a rise of sea level in the Holocene, when thick sequences of alluvial deposits were laid down in the previously incised channels. These later deposits include the Alluvium of the Dearne, Dove, Don and other rivers.

The few outcrops of River Terrace Deposits , typically comprising sand and gravel in the district are largely restricted to the Don valley and possibly relate to a single aggradation at a time when base levels were maintained about 5 m above that of the present-day alluvial flats.

The lower flanks of the main valleys, the floors of some tributary valleys and some of the isolated cols are mantled by spreads of soliflucted material and hillwash — Head . However, these are generally difficult to delineate in any consistent fashion, and are thus largely unmapped. Comparable deposits occur at the foot of the Permian escarpment and in dry valleys on the Permian formations. Typically, the composition of these deposits reflects that of the parent materials upslope and commonly is of angular sandstone or dolomitic limestone fragments in a matrix of sandy clay or clayey silt. A thickness of 2 to 4 m is thought to be fairly typical for the major developments of Head. Such deposits are commonly thicker on north- and east-facing slopes. Alluvial Fan Deposits have been mapped at one location [SE 511 121] near Skelbrooke, where they represent the accumulations of a minor tributary valley.

The floodplains of the major rivers and their tributaries are underlain by Alluvium that can exceed 10 m in thickness in the major valleys. Typically, an upper unit, up to 5 m in thickness, consists of soft to firm, brown and grey mottled, silty clay. Locally, organic peat-rich horizons may be present and commonly there is a sand or gravel component which increases downwards. The lower unit, about 3.5 m thick, comprises fine- to coarse-grained sands and angular to rounded gravel in varying proportions; a variable clay content is also present. At many urban locations, the silty or clayey upper unit of the alluvium has been removed prior to the construction of foundations and commonly replaced by fill material.

A limited extent of Peat is developed on high ground in the south-west of the district, at Edge Mount [SK 275 937].

Superficial structures

The bedrock strata are thought to be affected locally by the associated processes of cambering and valley bulging, though not on any great scale. Cambering may occur where sandstone or limestone overlies mudstone and caps the higher ground. Valleyward movement of the upper unit is caused by mass-wasting of the underlying mudrocks. It results in a draping effect, with consequent fracturing to form dip-and-fault structures. Fissures ('gulls') between the individual blocks may be filled with drift, or remain as open voids. Cambering is particularly common along the crest line of the Cadeby Formation escarpment. Along the valley floors, lateral pressures exerted on mudrocks may result in the formation of locally faulted anticlinal structures or valley bulges which, in poorly exposed stream beds, are characterised by aberrant steep dips. Such features are probably more common in the more deeply incised tributary valleys. Valley bulging at the Round Green opencast coal site [SE 333 038] was described by Shotton and Wilcockson (1949) in one of the early papers on this topic.

The topography of the district is generally subdued, and localised natural landslides are largely restricted to the steeper slopes of Namurian strata in the south-west. It is possible that, beneath the steeper slopes which have been subject to camber movements on the Permian escapement, the mudstones may contain bedding-plane shears which could be reactivated by excavation work.

Artificially Modified Ground

Artificial Deposits have been delineated during field survey, and by examination of archival topographic maps, aerial photographs and site investigation data. Only the more obvious areas of modified ground can be mapped by these methods, and the boundaries shown may be imprecise; further generalization of the boundaries of these deposits has taken place during compilation of the 1:50 000 map.

Infilled Ground is mapped where the ground surface has been excavated and partly or wholly backfilled. Mineral excavations, notably opencast mining operations and quarries, have commonly been filled with spoil or imported waste. Where such excavations have been restored there may be no surface indication of the extent of the backfilled void. Made Ground includes artificially raised ground, including landfill sites and embankments. Large areas of colliery spoil (Plate 6) are present in the Don and Dearne valleys e.g.[SE 450 015] and between South Kirkby and Hemsworth [SE 450 120]. Construction of urban areas commonly takes place on compacted rubble and fill. Spoil heaps associated with workings in the Tankersley Ironstone have been locally adapted for recreational purposes, including a golf course (Plate 7a) and (Plate 7b).

In the district, areas of Worked Ground represent voids from which natural material has been removed, for example, areas associated with mineral extraction at quarries (Plate 8), and road and rail cuttings.

A further two categories of artificially modified ground have been mapped at 1:10 000 scale but are not shown on the 1:50 000 map for reasons of clarity. These include Disturbed Ground (which includes areas of bell-pitting for coal and ironstone) and Landscaped Ground, which includes areas of shallow cut-and-fill, for example, in industrial estates or sports grounds.

Structure

The main structures referred to in this section are shown on (Figure 1); further detail concerning the regional structure can be found in Kirby et al. (2000). The district lies to the south of the Morley–Campsall (–Askern–Spital) fault zone, which in the Wakefield district to the north forms one of the main structural elements that influenced sedimentation and subsequent structural development in this part of the Pennine Basin (Lake, 1999). The strata in the Barnsley district dip gently north-eastwards for the most part, although the Don Monocline, with south-easterly dipping strata, is of considerable influence in the south-east. Minor north-south-trending folds in the north-eastern part of the district were formed in the zone of convergence of the Askern–Spital and Don structures.

Along the central northern margin of the district, the structure is dominated by the south-west-trending Badsworth Trough. The trough is bounded by the Moor Top Fault (and its splay) and the Mutton Flatt Fault. The components of the Moor Top Fault have a total throw to the south-east approaching 200 m, whereas the Mutton Flatt Fault has a throw of 110 m to the north-west. The nearby Shafton Fault has a downthrow to the south-east of over 120 m locally.

Throughout much of the Coal Measures outcrop to the south, the structure is dominated by at least three east-south-east-trending faults; for example those of Wortley Hall, Silkstone and Mapplewell together with their continuations. The last two named show a tendency to produce numerous splays eastwards. Subordinate, largely impersistent, north-east-trending faults also occur. The fault throws are generally smaller hereabouts, typically less than 30 m. Exceptional larger faults include Champany Hill (throw up to 120 m), Dearne Valley, and Thorpe Hesley.

Curiously, few of the faults link south-eastwards into the North Don fault zone, which forms the northern bounding structure to the Don Monocline. This monocline increases in prominence south-westwards and is bounded to the south-east by the South Don Fault Zone, which is possibly more intimately associated with the Don Monocline.

To the south-east of the South Don fault zone, the strata lie at the western end of the Finningley Syncline, which eastwards in the Doncaster district complements the anticlinal Askern–Spital structure to the north (Gaunt, 1994).

The Permian and Triassic rocks have a simple structure, consisting of a regional dip of less than 3° towards the north-east. Folds are very localised; they are possibly controlled by the same faults that cut the Coal Measures and reactivated during the development of the Cenozoic Alpine Orogeny. The rejuvenated fault throws are generally small, commonly less than 20 m, and some faults developed splay components as they were transmitted upwards through the younger strata.

Chapter 3 Applied geology

The legacy of mining and quarrying associated with the development of heavy industry in the district is large and has left areas of derelict and despoiled land. By considering the nature of earth science issues at an early stage in the planning process, however, appropriate decisions may be taken concerning opportunities for, and the nature of, site development.

Mineral resources

The economics of underground mining are currently unfavourable and consequently mineral resources are those that can be worked close to surface. The main factors hindering opencast extraction are significant thicknesses of overburden, sterilisation of resources by urban development and possible detrimental effects on the landscape and environment.

Quarries that have not been backfilled represent an important resource because they may provide a suitable void for waste disposal, may be reopened as a source of minerals or may be developed as sites of educational, recreational and wildlife value.

Engineering ground conditions

The most important ground conditions relevant to construction and development are the suitability of the ground to support structural foundations, the ease of excavation and the use in engineered earthworks and fills. These issues are summarised for the main engineering geological units in the district in (Figure 6). Foundation conditions are not only affected by the engineering properties of the local geology, but also by factors such as the geological structure, slope stability, the presence of undermining and the depth and degree of weathering. Variable man-made ground conditions, notably from landfill sites and areas of colliery spoil, may be a potential problem with respect to severe differential settling. Colliery spoil may contain iron pyrites that is prone to oxidise and produce sulphate-rich acidic leachates, which may be harmful to concrete present in foundations or buried services, thus requiring the use of sulphate-resisting cement. This oxidation process may also result in expansion and differential heaving of foundations constructed on such deposits. Large volumes of quarry spoil are present in the district, and the areas affected may present poor foundation conditions if large cavities are present, or where the spoil was deposited on steep slopes.

Mining subsidence

Mining in the Barnsley district has a long history, and includes the extraction of coal, fireclay, ganister, ironstone, building stone, and sand. Of these, coal and fireclay have been of greatest importance, and their exploitation dates back to at least the 13th century. Subsidence due to mining represents a significant hazard in the area. This has largely developed due to the collapse of abandoned underground workings and their access routes such as shafts and adits. Coal mines tend to be shallower and older in the western part of the district, and these older mines, using partial extraction methods such as 'bell-pitting' or 'pillar and stall' working, produce more concentrated subsidence features than modern long-wall methods which tend to affect larger areas but less severely. As a result of these factors the subsidence hazard is likely to be more severe in the western part of the district. It is known that mining subsidence can be particularly severe in the vicinity of fault zones, and can give rise to significant linear subsidence features (Taylor, 1968: Young and Culshaw, 2001).

Care should be taken with mining records as they occasionally use the word 'quarry' for what was, in effect, a mine (Arup, 1990). Shafts represent a hazard, particularly where either incompletely or poorly backfilled. Similarly, adits may have been blocked without being backfilled. Mine collapse may be delayed for many years following abandonment, depending on the type and size of working and changes in the ground-water regime. Modern geophysical (McCann et al., 1987), thermal imaging, and other remote techniques may successfully detect old workings.

Fireclay mining has been widespread from the late 1800s, particularly in the western part of the district, from where currently about 10 percent of Britain's non-refractory (i.e. bricks, pipes and tiles) products are sourced. This is either in tandem with coal and ganister mining or as a separate venture. The fireclay-bearing strata are found towards the upper part of the Pennine Lower Coal Measures Formation and Pennine Middle Coal Measures Formation, and to a lesser extent within the Millstone Grit. Mining was historically carried out principally using 'pillar and stall' methods; clay is currently being extracted at Stairfoot [SE 380 050] and Grimethorpe [SE 412 081]. The Pot Clay (Millstone Grit) was mined in the 18th century for pottery and brick clay in the Swinton area [SK 450 990].

Sand and sandstone were mined in the 18th to mid 20th centuries, principally for the glass industry, from the Yellow Sands Formation, using 'pillar and stall' methods with access adits. Lead was mined in the south-west of the district, along Ewden Beck [SK 295 395]. These 17th century excavations resulted in characteristic lines of shafts and associated spoil mounds apparently following the veins of galena. Ironstone mining was begun by 12th century monks in the south of the area around Thorpe Common [SK 374 951], and near Barnsley at Stainborough [SE 302 023], probably using bell pits. The Mexborough Rock has been quarried for building stone. Limestone is currently extracted from quarries at Warmsworth [SE 537 005], Cadeby [SE 521 002], Glen [SK 545 947] and Hazel Lane [SE 500 109] (McEvoy et al., 2006).

Dissolution subsidence

Natural dissolution of carbonate rocks, and evaporites contained within non-carbonate rocks, represents a potential subsidence hazard. The large-scale subsidence due to the dissolution of gypsum within the Edlington and Roxby Formations experienced at Ripon, North Yorkshire (Cooper, 1998) is not matched in the Barnsley district, due in part to a southward reduction in gypsum content of these strata. However, the BGS gypsum subsidence hazard ratings for the Brotherton and Cadeby Formations in the district are 'low' and 'low' to 'moderate', respectively. Caves are found within the Cadeby Formation, typically sited close to river level, in the Conisbrough [SE 528 992], Hampole [SE 498 112] and South Elmsall [SE 483 116] areas (Gibson et al., 1976).

Slope stability

Within the BGS national landslide database there are 41 landslides recorded for the Barnsley district, of which 18 are derived from previously published BGS maps. A large proportion of the more extensive landslides are situated in the south-west of the area within the Millstone Grit outcrop, to the south of Stocksbridge. The largest of these is 'Canyards Hills', on the south flank of Broomhead Reservoir, to the south-west of Ewden Village [SK 260 955] (Bendelow, 1944; Cross, 1988). In this complex of deep-seated rotational landslides, there are fine examples of 'ridge-and-trough' features, as well as mudslides, and the area is listed as an English Nature conservation site (Jones and Lee, 1994).

The presence of a landslide indicates significant ground movement past or present (occasionally both), and hence represents a hazard. Landslides developing within man-made deposits (e.g. colliery waste) are also potentially hazardous, particularly where they become saturated and are situated above a long run-out path. Ancient landslides may be reactivated by earthmoving and other engineering operations, by natural erosion, and changes to the hydrogeological regime, including water leakage or drainage failure in the vicinity of the landslide. Where possible, any form of development on landslides should be avoided, and special precautions should be exercised when site investigations are carried out on or near landslides.

Dissolution of limestones and evaporites

In Britain, sulphates occur naturally, mainly in the form of primary gypsum and anhydrite, but also in a secondary form derived from pyrite (iron sulphide), within several types and ages of rock. Gypsum is the more stable hydrated form of calcium sulphate under near-surface conditions and is found as beds, veins, and nodules. In the Barnsley district, the main sources of primary sulphate, in the form of gypsum, are the Edlington and Roxby formations. The adjacent dolostones and limestones of the Brotherton and Cadeby formations allow transport of sulphate-rich water. Secondary sulphate, derived from pyrite, is mainly found in the Coal Measures mudstones. High sulphate concentrations in groundwater have been found associated with colliery spoil tips (Meigh, 1968), and also in non-sulphate bearing strata due to sulphates being transported from the source rock through permeable material, such as alluvium (Forster et al., 1995).

Pollution potential

This is particularly applicable to artificial deposits (Made and Infilled Ground) that may contain toxic residues, either as a primary component or generated secondarily by chemical or biological reactions. Significant sites of potential pollution include areas of landfill and former gasworks, chemical works, textile mills, foundries, railway sidings and sewage works. Leachate migration may be a problem where groundwater percolates through waste and becomes enriched in potentially harmful soluble components. The problem may be enhanced in fractured bedrock because the discontinuities may provide pathways for leachate migration. Mine-drainage waters may present a problem near former mine workings because of their high pH, common elevated levels of manganese, aluminium and sulphates, and in addition, iron precipitation.

Gas emissions

Mine gas may be generated from both underground colliery workings and from colliery spoil at the surface, both prevalent within, and to some extent beyond, the Coal Measures outcrop. These gases include components of methane, carbon dioxide, and carbon monoxide. Gases, in particular methane, can also be generated from natural deposits such as carbonaceous mudstones. Such gases are able to travel significant distances from their source through fissures; either natural or related to mining subsidence. Where these gases are allowed to collect, fire or explosion may result.

Radon is a natural radioactive gas produced by the radioactive decay of radium and uranium. Radon is found in small quantities in all rocks and soils, although the amount varies from place to place. Geology is the most important factor controlling the source and distribution of radon (Appleton and Ball, 1995). 'Radon Affected Areas' have been declared by the Health Protection Agency (HPA, formerly NRPB) where it is estimated that the radon concentration exceeds the 'action level' of 200 Bq m⁻³ in 1% or more of homes (Green et al., 2002). Approximately half of the Barnsley district has been identified by the HPA as 'Radon Affected'. Dolomitic limestones of the Cadeby and Brotherton formations and sandstones of the Middle Coal Measures are identified as having the highest radon potential in the Barnsley district.

Radon that enters poorly ventilated enclosed spaces such as some basements, buildings, caves, mines, and tunnels may reach high concentrations. Inhalation of the radioactive decay products of radon gas increases the chance of developing lung cancer. Radon protective measures may need to be installed in new dwellings (and extensions to existing ones) in areas where it is estimated that the radon concentration exceeds the Action Level in 3% or more of homes (Building Research Establishment, 1999).

Water resources

Reservoirs provide an important source of water for domestic supplies. Groundwater also provides water supply and licensed water abstraction for industrial purposes. The Carboniferous sandstone units in the district are classified as minor aquifers, and the intervening mudstones are confining beds. The Millstone Grit sandstones are considered to provide higher quality groundwater supplies than Coal Measures sandstones, which tend to have high concentrations of sulphates, iron and trace metals. Faults may act as a conduit for groundwater flow, potentially increasing yields from boreholes, but faults with large displacements may reduce the interconnectivity of aquifer sandstones, thus limiting groundwater flow.

In the Permian sequence, the Edlington and Roxby formations are confining beds, greatly slowing water flow between the limestone aquifers of the Cadeby and Brotherton formations. Some hydraulic continuity between the limestone formations exists via fault and joint zones through the intervening strata. The evaporites in the confining beds may affect water quality within the adjacent aquifers, and the contained gypsum bands, particularly in the Roxby Formation, may contribute to the mineralisation of groundwater in the underlying aquifers. For example, in the Cadeby Formation, open solution joints are found locally at considerable depths, and similarly, the Brotherton Formation contains much open jointing due to dissolution collapse. The transmissivities of the dolomitic limestone aquifers are very variable and are mainly dependent upon faulting, jointing and karstic weathering, although some intergranular storage exists, especially within localised reefs (Aldrick, 1978). Groundwater quality within the limestone aquifers is naturally hard and deteriorates down-dip where the limestone is confined; the gypsum in the Roxby Formation increases the sulphate content.

Information sources

Enquiries concerning geological data for the district should be addressed to the Manager, National Geological Records Centre, BGS, Keyworth. For information on wells, springs and water borehole records contact: BGS Hydrogeological Enquiries, Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB Telephone 01491 838800 Fax 01491 692345.

Other geological information held by the British Geological Survey include borehole records, fossils, rock samples, thin sections and hydrogeological data. Searches of indexes to some of the collections can be made on the web site, which also gives access to the BGS Lexicon of named rock units and the photographic collection. BGS catalogue of maps and books is available on request (see back cover for addresses).

Maps

• 1:50 000
• Sheet 87 Barnsley (Bedrock and Superficial) 2007
• 1:25 000
• Sheet SE30 Barnsley (Solid and Drift Geology) 1987
• 1:10 000
• The maps covering the 1:50 000 Series Sheet 87 Barnsley are not published, but are available for public reference in BGS libraries in Keyworth and Edinburgh and the London Information Office in the Natural History Museum, South Kensington, London. Full colour digital copies are available for purchase from BGS Sales Desk. Copies of the fair-drawn maps of the earlier surveys may be consulted at the BGS Library, Keyworth. Many BGS maps are available in digital form, which allows the geological information to be used in GIS applications. These data must be licensed for use. Details are available from the Intellectual Property Rights Manager at BGS Keyworth. The current availability can be checked on the BGS web site.
• Geophysical maps
• 1:1 500 000
• Colour shaded relief gravity anomaly map of Britain, Ireland and adjacent areas, 1997 Colour shaded relief magnetic anomaly map of Britain, Ireland and adjacent areas, 1998
• Geochemical atlas
• Regional geochemistry of Humber–Trent: stream water, stream sediment and soil. In press.
• Data from the Geochemical Baseline Survey of the Environment (G-BASE) are also available in other forms including hard copy and digital data.
• Hydrogeological maps
• 1:625 000
• Sheet 1 (England and Wales) 1977
• 1:100 000
• Southern Yorkshire and adjoining areas (Sheet 12), 1982
• Groundwater Vulnerability Map, South Pennines (Sheet 11); produced by the Environment Agency.

Books and reports

• British regional geology: the Pennines and adjacent areas. Fourth edition. 2002
• Barnsley, Sheet 87 England and Wales. Memoir of the Geological Survey, 1947, reprinted with minor amendments 1954.
• The Pennine Lower and Middle Coal Measures formations of the Barnsley district. British Geological Survey Internal Report, IR/06/135.

Documentary collections

Boreholes and shafts

Borehole and shaft data are catalogued in the BGS archives at Keyworth. For the Barnsley district, the collection consists of the sites and logs of about 7000 boreholes. For further information contact: The Manager, National Geosciences Records Centre, BGS, Keyworth.

Mine plans

BGS maintains a collection of plans of underground mines for minerals other than coal, mostly for sandstone and fireclay.

Geophysics

Gravity and aeromagnetic data are held digitally in the National Gravity Databank and the National Aeromagnetic Databank at BGS Keyworth. Seismic reflection data is available for parts of the district.

Material collections

Palaeontological collection

Macrofossils and micropalaeontological samples collected from the district are held at BGS Keyworth. Enquiries concerning the material should be directed to the Curator, Biostratigraphy Collections, BGS Keyworth.

Petrological collections

Hand specimens and thin sections are held in the England and Wales Sliced Rocks collection at BGS Keyworth. A collection database is maintained and charges and conditions of access to the collection are available on request from BGS Keyworth.

Borehole core collection

Samples and entire core from a small number of boreholes in the Barnsley district are held by the National Geosciences Records Centre, BGS, Keyworth

BGS (Geological Survey) photographs

Photographs used in this sheet explanation are held in the BGS library, Keyworth. Copies can be supplied at a fixed tariff.

Other relevant collections

Coal and ironstone abandonment plans

Copies of abandonment plans are held by the Mining Records Office, Coal Authority, 200 Lichfield Lane, Berry Hill, Mansfield, NG18 4RG, Telephone 01623 638233. These plans are held by the Coal Authority in the public domain, but are not available for reference at BGS.

Fireclay abandonment plans

Fireclay abandonment plans are held by the Health and Safety Executive, Rose Court, 2 Southwark Bridge, London, SE1 9HS.

Mining, general

Further information regarding mining in the Barnsley district is available from the South Yorkshire Mines Advisory Service (SYMAS), Barnsley MBC, Town Hall, Barnsley, South Yorkshire, S70 2TA.

Groundwater licensed abstractions, Catchment Management Plans and landfill sites Information on licensed water abstraction sites, for groundwater, springs and reservoirs, Catchment Management Plans with surface water quality maps, and extent of washlands and licensed landfill sites are held by the Environment Agency.

Earth science conservation sites

Information on Sites of Special Scientific Interest (SSSI) within the Barnsley district is held by English Nature, Northminster House, Peterborough, PE1 1UA.

Information on Regionally Important Geological and Geomorphological Sites (RIGS) is held by UKRIGS, National Stone Centre, Porter Lane, Middleton-by-Worksworth, Derbyshire DE4 4LS.

References

British Geological Survey holds most of the references listed below, and copies may be obtained via the library service subject to copyright legislation (contact libuser@bgs.ac.uk for details). The library catalogue is available at: http://geolib.bgs.ac.uk

Addison, R, Waters, C N, and Chisholm, J I. 2003. Geology of the Huddersfield district —a brief explanation of the geological map sheet 77 Huddersfield. Sheet Explanation of the British Geological Survey.

Aldrick, R J. 1978. The hydrogeology of the magnesian limestones between the River Wharfe and the River Aire. Quarterly Journal of Engineering Geology, Vol. 11, 193–201.

Appleton, J D, and Ball, T K. 1995. Radon and background radioactivity from natural sources: characteristics, extent and the relevance to planning and development in Great Britain. British Geological Survey Technical Report, WP/95/2.

Arup. 1990 Review of mining instability in Great Britain (DOE.) Vol. 1/viii.

Bedrock, M. 1984. Sedimentology of some Westphalian C sequences in the Yorkshire Coalfield. Unpublished PhD thesis, Royal School of Mines, University of London.

Bendelow, L. 1944. Remedial works in connection with the Waldershelf slip Broomhead Reservoir. Journal of the Institution of Civil Engineers, 95–105.

Besly, B M, and Fielding, C R. 1989. Palaeosols in Westphalian coal-bearing and red-bed sequences, central and northern England. Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 70, 303–330.

Brettle, M J. 2001. Sedimentology and high-resolution sequence stratigraphy of shallow water delta systems in the early Marsdenian (Namurian) Pennine basin, northern England. Unpublished PhD thesis, University of Liverpool.

Bristow, C S. 1988. Controls on sedimentation of the Rough Rock Group (Namurian) from the Pennine Basin of northern England. 114–131 in Sedimentation in a synorogenic basin complex:the Upper Carboniferous of north west Europe. Besley, B M, and Kelling, G (editors). (Glasgow and London: Blackie.)

Building Research Establishment. 1999. Radon: guidance on protective measures for new dwellings. Building Research Establishment, B R211.

Cochrane, S T. 1991. Aspects of the geology of the Barnsley Seam in the northern part of the Yorkshire Coalfield. Unpublished manuscript of a paper given at the Geological Society Coal Geology Group Meeting, Sheffield 1991.

Collinson, J D. 1988. Controls on Namurian sedimentation in the Central Province basins of northern England. 85–101 in Sedimentation in a synorogenic basin complex: the Upper Carboniferous of north west Europe. Besley, B M, and Kelling, G (editors). (Glasgow and London: Blackie.)

Cooper, A H. 1998. Subsidence hazards caused by dissolution of Permian gypsum in England: geology, investigation, and remediation. 265–275 in Geohazards in engineering geology. Maund J G, and Eddleston, M. (editors). Geological Society of London, Engineering Geology Special Publication, No. 15.

Cross, M. 1988. An engineering geo-morphological investigation of hillslope stability in the Peak District of Derbyshire. PhD thesis (unpublished). University of Nottingham.

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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 Earth Galleries, and from BGS-approved stockists and agents.

Figures and plates

Figures

(Figure 1) Summary of the geology and main structures of the district.

(Figure 2) Principal marine bands found in the district.

(Figure 3) Stratigraphy from Warmsworth Borehole geophysical log. Vertical scale is in metres below kelly bushing of borehole.

(Figure 4) Named Westphalian sandstones of the district.

(Figure 5) Named coal seams of the district.

(Figure 6) Engineering geological classification of major formations/deposits.

Plates

(Plate 1) Woolley Edge Rock, Burton Bank [SE 354 078], Barnsley. Up to 6.5 m cross-bedded fluvial sandstone showing overall upward-fining of grain size and reduction in bed thickness (photograph taken June 2006; P645704).

(Plate 2) Glass Houghton Rock, Cudworth [SE 382 087]. Abandoned quarry section (c. 10 m high) of cross-bedded sandstone, with palaeoflow directions towards the south-west, away from the main body of the sandstone (photograph taken June 2006; P645706).

(Plate 3) Silver Wood Sandstone Quarry, Ravenfield [SK 484 939]. The working face in the Ravenfield Rock can be seen to the left; to the right, finished curb and pulp stones are dressed and ready for export to the USA (photograph taken September 1936; P206903)

(Plate 4) Sandstone from the Brierley Member of the Pennine Upper Coal Measures, exposed in a disused railway cutting between Brierley and Hemsworth [SE 410 119] (photograph taken 1973; P223235).

(Plate 5) Watchley Crag, Bilham, near Hooton Pagnell [SE 475 067]. Lowest beds of the Cadeby Formation resting on the Yellow Sands Formation, the junction being just below the hammer (Photograph taken August 1930; P205103).

(Plate 6) Coal spoil tip reclamation, Grimethorpe [SE 412 078]. In a bid to improve the environment, many spoil tips have been redeveloped for a variety of uses, including industrial, public open space, woodland and agriculture. The spoil tip is approximately 30 m high (photograph taken June 2006; P645707).

(Plate 7a) Tankersley Park c.[SK 351 988]. Spoil from regularly spaced shafts on the dip-slope of the sandstone above the Tankersley Ironstone (photograph taken October 1936; P206885).

(Plate 7b) Tankersley Park c.[SK 351 988]. The spoil tips, landscaped and restored, are a feature of a golf course [SE 354 986]. (photograph taken June 2006; P645699).

(Plate 8) Hampole Lime Works [SE 516 097]. Workings in the upper part of the Cadeby Formation. The kilns are built into the rock face to retain heat and facilitate handling of the limestone (photograph taken August 1930; P205107).

(Front cover) Wharncliffe Crags [SK 297 975] (a Geological SSSI) are formed by two sandstone beds that together comprise the Wharncliffe Rock, from the Pennine Lower Coal Measures Formation. The sandstone beds preserve an excellent example of a fluvial meander belt, with cross-bedding indicating lateral accretion on a point-bar, and soft-sediment deformation structures. The coarse grain size of parts of the Wharncliffe Rock made it well-suited to the manufacture of querns, small stones used to grind cereals, which were made in this area during Iron Age to Roman times. (Photograph P Witney; P662704).

(Rear cover)

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

Figures

(Geological succession) Geological succession in the Barnsley district

(Figure 2) Principal marine bands found in the district.

(Figure 4) Named Westphalian sandstones of the district.

(Figure 5) Named coal seams of the district

(Figure 6) Engineering geological classification of major formations/deposits