Geological notes and local detailsfor

Sheet NZ 27

Cramlington, and Wide Open

(SI3 Northunberland) NaturalEnvironment Research Council

BRITISH GEOLOGICAL SURVEY

Geological notes and local details for

Sheet NZ 27

Cramlington, Killingworth and Wide Open

(SE Northunberland)

Part of 1:50,000Sheets 14 (Plorpeth)and 15 (Tynenouth)

I. Jackson, D.J.D. Lawrenceand D.V. Frost

Bibliographicreference: JACKSON, I., UMRENCE, D.J.D. and FROST, D.V. 1985. Geologicalnotes and local details for Sheet NZ 27 (Cramlington,Killingworth and Wide Open) (Ne-Jcastle uponTyne: BritishGeological Survey)

Authors: I. Jackson, BSc, D.J.D. Lawrence, BSc, and D.V. Frost, BSc, PhD BritishGeological Survey, Windsor Court, Windsor Terrace, NE2 4HE

\ Productionof this report was supported by theDepartment of theEnvironment, butthe views expressed in it arenot necessarily those of the Departnent.

Crown copyright1985 BRITISH GEOLOGICALSURVEY, NEYCASTLE 1985 2

The geology, mineral resources and geotechnical problems of the Cramlington -

Killingworth - Wide Open area (SheetNZ 27) are described. Lower and Middle .. - .- . . .- - Heasures (Westphalian A, B and .C), -of 'fluvial and deltaicfacies, are

650m thick, with 14 workable . Devensian glacial sediments up to 5Om

thick conceal the Coal Measures which are well known through numerous shafts,

bores and mines. Coal has been mined extensively, but resources remain which

could be worked opencast. Geotechnical problems result from subsidenceover

shallow coal workings and shafts, many of which are inadequately documented.

Weak clays and silts in the glacialsequence may also cause foundation problems . 3

PREFACE

Thisaccount describes the geology of 1:25,000 sheet NZ 27 which lies within 1:50,000 geologicalsheets 14 (Xorpeth) and 15 (). The resurvey was commissioned by Department of theEnvironment.

The area was first surveyed at thesix-inch scale by H.H. Howelland W.

Topley,and published on Old MeridianCounty maps duringthe years 1867 to 1871. A re-survey by G.A. Burnettand V.A. Eylesin 1929-34 was publishedon the New Heridian.Revision of theeastern half of the area by

D.H. Land during 1960-3 was publishedon National Grid sheets NZ 27 NE and SE.

There is a nemoirfor the Tynemouth district (Land1974) but not for the

Xorpeth district.

The presentsurvey was made in 1983-4by I. Jackson (NZ 27 NW and SW),

D.V. Frostproject leader (27 SE), and D.J.D. Lawrence(27 NE), with D.H. Land as programmemanager.

G.N. arown

Director,British Geological Survey

Xarch 1985 . 4

CONTENTS

pa JC : SU?IMARY 2

PREFACE 3

LIST OF FIGURES 5

INTRODUCTION 6

GEOLOGICAL HISTORY 8

COAL IYEASURES GEOLOGY 8

Sedimentology 11

Structure 12

Stratigraphy 15

Lower Coal Xeasures 15

Middle Coal Measures 16

IGNEOUS DYKES 21

QUATERNARY 22

Rock-head 22

Quaternary deposits 26

XINEEIAL RESOURCES 28

GEOLOGICAL IMPLICATIONS FOR LAW USE PLANNING 30

Coal ?lining 30

GeotechnicalProperties 32

Made ground 35

CONCLUSIONS 38

SELECTED BIBLIOGRlLZIY 39 5

LIST OF HAPS and FIGURES

MAPS at 1:10,000 scale For each of four themes there are four maps,for NZ

27 NW, NZ 27 X, NZ 27 SW and NZ 27 SE respectively. The geological maps are overprinted on Ordnance Survey top.ographic.bases.

Geology

Rockhead elevation

Drift thickness

Borehole and shaft sites

M. APS at 1:25000 scale

Structure contours

Shallow coal workings

FIGURES in the text

1. Location map p.7

2. Generalized vertical section 9

3. Sinplified geological map 10

4. Horizontalsections 13

5. Quaternarydeposits 23

60 Kockheadelevation 24

7. Drift thickness contours 25

8. Made ground 36

NOTE: It is emphasized that the maps in this report shouldnot be used as a substitute for normal site investigation beforeany development. 6

INTRODUCTION

The area describedin this report lies northof Newcastle uponTyne and withinthe administrative counties of Tyne & Wear andXorthumberland. It extendsfrom Stannington and New Delavalin the north to Dinnington and

Killingworthin the south (Fig. 1). The RiverBlyth flows eastwards across thenorthern margin of the area in a deeplyincised valley; elsewhere relief is gentlyundulating from 30 to 78m above sea-level.

Inthe past, urban development was nomore than a scatter of small villagesusually sited on higher ground and built of locally quarried Coal

Measuressandstone. Coal mining, first recorded in the 13th century, slowly changedthe landscape. At first workings were only small scale near-cropbell pits and drifts.Production greatly increased after 1550 withan influx of capitaland improved technology which included railways and borehole drilling.

Before1699 a railwayran from near Plessey Checks through New Delavalto the coast at Blythm Theoldest borehole record is of onenear Killingworth Church drilledin 1694 to a depthof 65mm Inthe 19th century deep mines working large areas were developed,with a consequentialexpansion of settlements and population.

After1960, whenmost ofthe mines became exhaustedand the workforce moved, many of the rowsof terracedminers' houses became derelict.In the

1970'san attempt was made to arrest thedecline of the region with resettlement of peoplefrom central Newcastle andother urban areas to

Killingworth andCramlington new towns. New roads were made, oldcoal tips landscaped,opencast sites restored and builtover, and new factoryand trading estates developed.The remaining large areas ofopen covntryside in d thenorth and west includelarge country estates such as Blagdonand Seaton

Delaval .

Note:the word 'area',unqualified, in this account means thewhole ground covered by sheet NZ 27. 20

80 I I I

, . __ ..

BRENKLEY c==, -.- *\*

I-

DINNINGTON

N EWCASTLE AIRPORT Q:

F Q: GOSFC TH PARK /’ I NORTH

70 ?O

Major roads 0 1- 2 3 4 km

-.-.-.- County boundary

J Fig. 1. Location map. 8

GEOLOGICAL HISTORY

Carboniferousrocks underlie the area and were deposited some 300 million

yearsago in the Northumberland Trough which was a regionof relative

subsidencewith thick, rapid sedimentation between the Southern Uplands to the

northand the Alston Block to the South, Pre-Carboniferous rocks are

consideredto be strongly folded Lower Palaeozoic strata althoughno borehole

haspenetrated the 500Om thickCarboniferous.

At theend of Carboniferous times foldingand faulting were followedby

deposition of younger strata, since removedby erosion,and apart from

intrusionof Tertiary dykes together with further earth movements, the'solid'

geologicalhistory of the area was complete(Fig, 3).

However thelandscape continued to be modified, particularly by the

QuaternaryDevensian glaciation which ended about 12,000 yearsago. Most of

the area is coveredby glacial deposits or 'drift' (Fig. 5). Where these are

thin or absent,resistant Coal Heasures sandstonesform topographic highs.

The thickestdrift, perhaps in excess of 5h, infillspre-glacial or glacial

channelswhich cut into solid rock and descend eastwards to below sea level

(Fig. 6 and 7).

Small streams, such as Seatonand Korton burns, meander eastwards in

shallowvalleys with thin alluvial deposits. Only the River Blyth and its

tributariescut down throughthe drift to expose rock.

COAL MEASURES GEOLOGY

Withinthe area there are about 650m of Lowerand Xiddle Coal Xeasures

(Fig. 2), restingconformably on older Namurian and Dinantian strata. X11 but

thelowest 5hof the Coal Xeasures crop Out. The Lower CoalXeasyres are of

Westphalian X age;the Hiddle Coal Yeasures are Westphalian B (upto the

Ryhope XarineRand) and Westphalian Cm Mu-- Inferred position of Down Hill Marine Band

CLOUSDEN HILL

KILLINGWORTH

WEST MOOR metres FELL

USWORTH

Ryhope Marine Bznd

BURRADON Hylton Marine Band

BRUNTON QUARRY

Kirkby's Marine Band

RYHOPE FIVE-QUARTER RYHOPELITTLE y. -..... MOORLAND m]Sandstone -Coal .----M- High hlain Marine Bsnd ...... MarineBand b HIGH MAIN --- .. + Strata below this METAL level do not crop FIVE-QUARTER out on NZ 27 BENTINCK YARD

BENSHAM

DURHAM LOW MAIN

NORTHUMBERLAND LOW MAIN

TOP PLESSEY PLESSEY { BOTTOM PLESSEY

Harvey MarineBand

BEAUMONS HODGE TI LLEY TOP BUSTY ...... BOiTOM BUSTY 9.e. . *. * THREE-QUARTER

BROCKWELL

VICTORIA

Stobswood Marine Band MARSHALL GREEN :-(< GANISTER CLAY +k -...... :. ::;:.:.:.. .. 7.::::,:.:..- ?SALTWICK ...... Inferred position of Quarterburn Marine Band

Fig. 2 Generalized vertical section to

20

0

K KILLINGWORTH NLM NORTHUMBERLAND LOW MAIN RMB RYHOPE MARINEBAND HaMB HARVEYMARINE BAND - - - - Coal seam RFQ RYHOPE F IVE-QUARTER B BEAUMONT -L - Fault HM HIGHMAIN D DOLERITE YD YARDYD --- h’arine Band 7 d SCALE Dyke 0 1 2 3 4 krn - 1 I 1 I I

Fig. 3 Simplifiedgeological map 11

Sedimentology

The Coal Measures rocks consist chiefly of mudstones with subordinate siltstones, sandstones, seatearthsand coals in repetitive sequencesor cycles, with the lithologies commonly in that upwardorder. Each cycle is generally between 10 and 30m thick, and the thicker ones usually contain thick sandstones. The depositional environment was fluvial flood-plain to upper deltaic with occasional marineincursions.

Coals About 3% of the measures are coal,which in this area isof bituminous rank. Of the 30 named seams, some 12 are thick enough to be mined.

Lithologically, coals canbe divided into bright (softs), dull (hards), banded

(soft and hards), cannel, or dirty dependent upon their conditionsof deposition and type of original flora. The seams are consideredto have formed from vegetation whichgrew in situ, in swamps which were sufficiently de-oxygenated for the partial preservation of vegetable matter. Some seams are split by interdigitation of sediment, which may be on a regional scale or on a local scale, dueto local subsidence and sedimentation. All seams vary in thickness and some thin out altogether,although their position may be indicated by the seatearth persisting. Nany seams have 2 or 3 cm of cannel coal in their immediate roof.

Seatearths underlie all coal seams and grade from sandstone (ganister)to mudstone (fireclay). They are distinguished by the absence of bedding and the presence of rootlets. Once thought to be the soils in which coal forming forestJgrew, they ar2 now believed to represent a sub-aqueoussoil accumulation on which vegetation flourished without being preserved ascoal.

There is therefore no correlation between the thicknessor character of the seatearth and that of the overlying coal. Fireclays and ganisters may or may not be usable as refractories. 12

Mudstones form over 50% of theCoal Measures sequence. Colloquial terms are shale,bind, metal andplate. Mudstones immediately above a coal seam, grey topale grey in colour, generally contain fossil bivalves in 'mussel bands',

At fivehorizons, mudstones with marine fossils occur (marine bands), with foraminifera,fish scales, marinebivalves, Lingula sp. and in the Ryhope

Harine Band, goniatites.Faunas were notstudied in the present research.

By anincrease in silt contentmudstones grade into siltstones or pass by intercalation andinterlamination of sandybeds (striped beds) into sandstone

('post'or 'hazel').

Sandstones and siltstones compriseup to 45% of thetotal sequence. They are in the form ofthin (about 5m) butlaterally widespread sheets (sheet sandstones)or thicker channel sandstones with a gentlycurving form inplan.

Channelsandstones have erosive bases ('washouts') which cut down into underlying strata and may remove partof a coal seam. Practically all sandstones are cross-beddedon various scales and some show ripple marksand bioturbation.

Ironstones are most common in mudstones as nodules, lensesand 'bands', generallyconcentrated just above or below coals. Some nodules are septarian; thosein seatearths may occupycavities left by roots.

Structure

The Carboniferousrocks of thearea were faulted and gentlyfolded in the late-CarboniferousXercynian movenents, and later were gentlytilted eastT,.-ard withfurther smaller scale faultingin Tertiary tines (Fig. 4). The larger faults may bereactivated earlier deep-seatedfractures.

Foldingand faulting is shownon the 1:25000 scale structurecontours map whichshows contours at 3Om intervalson the widely workedYard and Bottom NZ27 NW Arcot Hdl NW (200 800) Shotton Stimrllnyton Rwer Blyth Mutres

2000 0 1000 I 1 METRES HORIZONTAL SCALE I

VERTICAL SCALE 2 x Horizontal

NZ 27 SE SE (300 700)

NW (IId 7b0) Burredon Dudley Merres

conunued from above Fig.4. Horizontal section 14

Busty coals. The general structural pattern is of gently tilted strata intersected by a conjugate series of faults trending NE and MJ. Dips average

3 to 4O4j k&S and SE. This overall pattern isinterrupted by a shallow syncline near and a corresponding anticline near Seghill. Some correlation is suggested between lateral movement along the NinetyFathom

Fault and small folds to the north of the fault both here andother in areas.

The Hazbrigg-West Cramlington Fault,striking NE and bisecting the area, is one of the longest and most important dislocations. It is intersected at its SW end by the Havannah-Weetslade Fault and terminatedNE to by the Hartley

Station Fault. These faults, together with the Crimea, West MoorSouth, West

Moor North and Burradon faults allhave throws of the order of3Om. The majority of the faults are smaller. Some die out gradually as their throws reduce, while othersare terminated abruptly by cross-faults. Host die out by splitting up into several fractures often with opposing throws, for example the Burradon Fault witha plexus of dislocations near Dudley.Faults with a throw of less than 3m are not shown on the structure contour mapbut are quite common, particularly in the area of very gentle dipping strata near Seghill.

All faults hadeup to 300.

One of the largest and structurally significant faultsof the

Northunberland Coalfield is the Ninety-Fathom Faultor 'Dyke', which crosses the SE corner of the area. It has a vertical displacement downnorth of some

170m near Killingworth Hoor and a hade of 45O. Most low-angle faults of this type show evidence of transcurrent novement. ?fining information proves that the dip of the strata as they approachthe downthrow side of the fault

/ increases to 450 so that they meet the fault plane at right angles.On the upthrowstratatheside are littledisturbed. -7 Renewed earth novementsin Tertiary tines reactivated many faults, and intrusion of dykes occurred at this tine. Sone of these occupy fault planes whilst others are displaced by them. 15

Stratigraphy

Lower Coal Measures

Stratabelow the Marshall Green Coal are only poorly known from a small number ofboreholes. The inferred position of the Quarterburn brine band, marking the base ofthe Coal Measures, is 75m belowthe Narshall Green Coal.

Intervening strata are largelysandstone with three thin coals tentatively correlatedwith the BottomSaltwick, the Saltwick and the Ganister Clay coals.

The Marshall Green Coal is thelowest known tocrop out in the area, and is 48 to 79cm thick. Strata abovethe Marshall Green are exposed in Catraw

Burn west ofStannington. They are predominantlysandstones, coarse in places, andinclude a 2.5 m mudstonebed overlying the thin Stobswood coal; themudstone contains fish debris indicative of the Stobswood Marine Band [207

7951. .

The Victoria Coal lies about 10m abovethe Stobswood seam. Near

Stannington it forms anoutlier which has been worked over a small areafrom drifts in Catraw Burnand from Church Pit, where the section shows 1.82m of coalincluding a parting.Elsewhere the seam is generally less than50ca thick.Sandstone again dominates the measures, soae 2Om thick, between the

Victoriaand the Brockwell but two thininpersistent coals occur. In theroof of thelower one is a mussel band characterised by largeCarbonicola pseudorobustaTrueman.

The Brockwell Coalcomonly contains dirt partings which in the north and west splitthe Sean intoseveral leaves. It hasbeen worked between Seghill andBackworth and SW of Dinnington.The naximw thickneses is 1.2m (inclusive of dirt bands),In places, for example near RurraZon, it is washed out. From theBrockwell to the Three-Quarter, strata between 15 and 24m thickcontain two thininpersistent coals and variablesandstones.

The Three-Quarter Coal hasbeen worked near Sackworth and south of the 16

NinetyFathom Fault where it reaches 77cm inthickness, but elsewhere it is generallythinner and in places represented by cannel.There are 13 to 20m of strata upto the BottomBusty. In the east, these are largelycoarse sandstone.

The Bottom Busty Coal,average thickness 80cm, attains a zlaximum thickness of 1.14m in the west, hasbeen opencasted south-west of Blagdon Hall and is currentlybeing mined from Colliery (the only working pit in thedistrict). Strata betweenthe Topand Bottom Busty, around 10m thick, include a thincoal and much sandstone.

TheTop Busty Coal,also currently workedfrom Brenkley Pit, hasbeen worked inthe past between Seghill and . Its averagethickness in theseareas is 80 and60cm respectively. It is subjectto washouts. The overlying 10 to 20m of stratainclude some sandstone.

The Tilley Coal is bandednearly everywhere. Several thin seams may be present;in the west two leaves(with individual thicknesses of less than 74cm havebeen proved and the seam hasbeen mined south of Seghill where it comprises 1.37m of alternatingcoal and dirt. In theinterval of between 8 and 20m betweenthe Tilley and the Beaumont seams are two thinimpersistent coals,one of which is more persistentin the west and is correlatedwith the

Hodge Coal.

The Beaumont Coal,which has an average thickness of about lm, hasbeen mined extensively and alsoopencasted in the north-west of the area. The 18m

(average) of strata betweenthe Beaumontand theHarvey Xarine Band are mostly mudstonebut with thick washout sandstones in places, which arz exposed in the mainroad cutting at Shotton [221 7741. Imediatelyoverlying the Beaumont is a thinfragmental clay rock followed by a musselband with many ostracods at its base.

Middle Coal Measures

The Harvey Harine Band, whichmarks the base of the Xiddle Coal Xeasures, consists of 30 to 90 cm of verydark grey to blackshale containing Lingula mytilloides J, Sowerby, fish scales andforaminifera, Overlying the marine band are mudstoneswith a musselband at thebase, TAocally the bands are washed-out, In West Hoor Borehole 27 SE/62 anintraformational conglomerate at thebase of a thicksandstone rests directly on themarine shales.

Sandstones up to 30m thickoccupy most of theinterval betweenthe Harvey

Xarine Band andthe overlying Plessey Coal,

The Plessey Coal takes its name fromthe eponymous locality [240 7901 where it was first minednear crop and where it is over lm thick.South-east of a linethrough Dinnington and Cradington it is in two thinleaves and it is commonly washed-out. It is beingopencasted W of Brenkleywhere it is 1.5n thickin two leaves,Pleasures between the Plessey and the Northumberland Low

Xain, some 20m inthickness, are variable in lithologybut sporadically contain a thincoal or seatearth tentatively correlated with the Hutton Coal,

Above thePlessey, though not in its immediateroof, is a prominentaussel band.The Plessey is notthick enough to be workablesouth of Cranlington, andthe Hutton is similarlytoo thin north of theRiver Tyne;moreover in this interveningregion of thin seams there are extensivesandstone washouts.

Correlation is thereforenot certain. Land (1974) thoughtthat the two coals were at differenthorizons, but the Coal Board correlate them,and call the

thinCheeveley coal (which underlies the Plessey) the 'Plessey'.

The Northumberland Low Main hasbeen worked over much of the area, some miningbeing prior to 1860. It approaches 2m inthickness, with only minor

v dirtbands, is of excellentquality with an ash contentbetween 4 and 10% and low sdphurbetween 0.8 and 2.5%. A band of thick coalreferred to as a

'swel&y'trends northwards from near Backworth (Hurst 1860, Land 1974). Wnile

theswelly is certainlycontemporaneous, because strata above and below are notaffected, its origin is uncertain.Overlying neasures up tothe Durham

Low ?fain coal are variablein both lithology and thickness, from 12 to 27m

thickwith sandstones prominent, and mussel bandsin the mudstones. The Durham Low Main Coalhas been worked opencast and in Seghill

Colliery,During the recent ainers' strike this coal was worked at crop SW of

HartfordBridge. A typicalsection of the seam is upperleaf of coal 53cm on dirt 28cm oncoal lOcm on dirt 20cm on basalcoal 25cm. Overlying strata, around 12m thick, are largelysandstone (the Table RocksSandstone or Low Main

Post), which was quarried at Brenkleyand Dinnington.

The Coalsuffers extensive east-west washoutsthrough

Shankhouse.North of these it is splitinto Top andBottom Benshan, about 6m apart andworked separately.South of the washouts it is worked as a single seam inthe SE part of the area, where a typicalsection near Killingworth is coal 68cm on dirt lOcm oncoal 50cm. Inthe west the seam containsseveral dirt bandsand is subject to washouts.Mudstone overlying the Bensham carries a musselband characterised by Anthraconaia pulchella Broadhurst. Yeasures betweenthe Bensham andYard coals average 20m inthickness, with the thick

SeatonSluice Sandstone in the northern part of thearea, A thincoal up to

45cm thickoccurs some 5m belowthe Yard Coal but has not been worked,

TheYard Coal is almostentirely workedout, It is remarkablyconsistent in its thickness,about lm,dbfexcellent quality. TheYard-Five Quarter interval is about 20m thickand includes the Bentinck Coal,which is usually thin and variablebut justified working in the recent miners strike at crop N of West Hartford. A musselband occurs in its roof. Below theBentinck, the strata are largelymudstone; above they are mostlysandstone.

The Five-Quarter Coalhas been worked extensively, It increasesin

thicknessfrom 70cm nearBackworth to over lm inthe Seghill area where it

closelyapproaches the overlying Metal Coal to form a seam up to 2.36m thick with a median dirt parting 50cx thick.The united seam is washed out over a widearea near Shankhouse and Sew Delaval. Strata betweenthe Five Quarter

and Xetal Coalsincrease in thickness from a mere parting in thenorth to

12m inthe south where they are largelysandstone,

The Metal Coal,about la thick,has been worked inthe north and east, 19

butin the south-west it is animpersistent seam up to 84cm thick. In the north it practicallyunites with theunderlying Five-Quarter and suffers washouts.The Metal to HighMain sequenceconsists mostly of sandstone, rangingin thickness from lorn south of Killingworthto over 45m at Acorn

Bank. Quarries at Cramlingtonold village are inthis sandstone.

The High Main Coal is thethickest seam worked in the area comprising some 2m of excellentquality coal which is now exhausted. It is poorly exposed inthe Blyth valley near East Hartfordwhere there are veryearly workings.South and east of Seghillpoor quality, thin coals named Crow Coal occurclose below the High Main proper. At WeetsladeColliery Lizzie Pit a bastardcoal nearly lm thick is present some 5m belowthe main seam. Around

East Cradingtonthe High Main thinsto about 0.5m. The intervalbetween the

'rIighMain Coal andthe High bin Xarine Rand variesfrom 18m of massive cross-beddedfine-grained sandstone (High Main Post)in the south and west near West Xoor [265 7051, to a metre of argillaceous strata at Burradonand farthernorth. A thincoal between 15 and 84cm thickunderlies the marine band.

The High Main Marine Band is represented by less than a metre of black

finelymicaceous shale with Lingula sp. Exceptin the extreme south-east, it

is eitherabsent or unrecognisedsouth of Shankhouse. Above themarine band

is a thick,prolific mussel band. Betweenthe marine band and the Xoorland

Coal,the strata are about 30m thick,and contain two thin impersistent coals.

Theupper part of thissequence is mostlysandstone, which is exposed inan

oldquarry [281 7411 atSeghill and underlies the village.

The Moorland Coal is over 60cm thickin the north, but is of poor

quality. It was recently worked opencast at Stickley Fam [281 7751. Strata

betweenthe Hoorland and the Ryhope Little coalsaverage 10m inthickness.

Fish scales havebeen recorded inthe roof of theXoorland. Sandstone is

exposed inan old quarry [279 7231 on thenorthern outskirts of Killingworth.

The Rphope Little Coalreaches a maximum thicknessof 84cm at Rackworth 20

Colliery, It was workedopencast in 1970 to depths of 20m at HavelockSite south of Seghill. A typicalcoal section showed a 25cnupper leaf separated by 18cm of shalefrom a 61cm lowerleaf. Locally the top leaf was washedout.

Detailedcorrelation of coalsabout this level in the north-east is uncertain,Measures between the Ryhope Little andRyhope Five-Quarter coals are some llm thickand in places include a cannel up to 33cm thick.

The Ryhope Piv-arter Coal is a complex seam withnumerous dirt partings,In the West Xoor Boreholethe total thickness is 1.5m. Individual leaves of coalreach a maximum thickness of half a metre. There is evidence of surfaceworkings on a small scale west of Backworth.Between the Ryhope

Five-QuarterCoal and Kirkby's Xarine Band there are some 12 to 20m of variableaudstones and sandstones with several thin unnamedunworked coals including a seam immediatelyunderlying the marine shales,

Kirkby's Marine Band is characterised by an alternation of marine and non-marinephases. In West Xoor Boreholethe band is 3.6m thickwith a non-marineparting of 0.36m. Stratabetween Kirkby's and Ryhope marine bands are some 60m thick,largely sandstone with the thin Brunton Quarry and

Burradoncoals and the Hylton Harine Band. The Brunton Quarry Coal, 18m above

Kirkby'sLXarine Band, is thinand locally washedout by theoverlying sandstone.The Hylton Marine Band is 30cm thick in West XoorBorehole and yieldedforaminifera and Lingula mytilloides, About 43 higher is the

Burradon Coalup to 2Scm thick. Its name derivesfrom the infilledquarry

[ 274373071 west of BurradonHouse where the coal and overlying sandstone were exposed.This medium tocoarse-grained sandstone, about 23m thickin its full development, is exposed in the main linerailway cutting [262 7271 S of

Dudley, was quarriedin Burradon Houseand East HouseFarm [289 71221 quarries andforms the ridge on whichKillingworth old village stands.

The Ryhope Xarine Band formthe base of Westphalian C strata. Its fauna includesforaminifera, Dunbarella sp., Posidonia sp., 'Anthracoceras'sp.

andLingula %, The marinemudstones also include a 13-em bedof ankerite 21

siltstone,or 'cank', Some17m of mudstonessucceed the Ryhope Xarine Band, and are overlain by the Usworth coal,which is 76cm thicknear Killingworth,

Overlyingstrata are mudstonesand thinsandstones with carbonaceous horizons, totalling 23m inthickness, and capped by the Hebburn Fell Coal which is in

twomain leaves, an upper some55cm thickseparated by 4m fromthe lower 75cm

thickleaf. Betweenthe Hebburn Fell Coal and the 40-cm KillingworthCoal 36m higher,there are fourcoals including the 70cm thick West Moor Coal.

Interveningstrata are mudstonesand sandstones. An estimated lob of strata succeedthe Killingworth Coal up to the inferred Down Hill Marine Band, which narksthe base of the UpperCoal Xeasures and comprises the highest stratum mapped inthe area, Nothing is known ofthese strata, exceptthat they

include a sandstone at least 10m thickwhich was formerlyquarried at Clousden

Hill [283 7021 andwhich overliesthe 50cm thick Clousden Bill Coal,

IGNEOUS DYReS

There ars two classes of intrusiveigneous dykes in Northumberland: a

suite of quartz-doleritesassociated with the Whin Sill andintruded some 295

millionyears ago in late Carboniferous times, and a suite of tholeiitic

doleritedykes of earlyTertiary age (about 60 millionyears) emanating from

theMull volcano of W Scotland,In coxposition both types are siailar but

show texturaldifferences in thin section,

Quartzdolerites A dyketrending just N of east is recordedon plans of the

High!lain Coal near High Fam [2857211 and is probably a quartzdolerite.

Tholeiiticdykes are narrow and occur in en echclon segmen.ts, discontinuous at

anyone level. The TynernouthDyke, about lm wide, is recordedover a length

of 650n in Beaumont workings at about -183m andagain at -12m inFive-Quarter

workingsbeneath Killingworth Hoor. A verynarrow segment of the Vhitley Wke

sone lOOm long was proved in Yard workings E295 7501 east ofSeghill and also 22

in Bensham workingsnearby. The Northand South Hartley dykes have been provedintermittently over an 8km length, at surfaceand in mining, running

WNW northof Cramlington. On thenorth bank of the River Blyth E223 7881 there is a smallold quarry in the dyke.

QUATERNARY

SuperficialQuaternary deposits include sediments of glacial origin presentover almost the entire district and post-glacial alluvium and peat which are restrictedto valleys and hollows (Fig 5).

Till (boulderclay) is thedominant glacial deposit; glacial sand and gravel is recordedin several boreholes and has been recognised at surfacein a fewscattered localities, whilst laminated silts andclays of glacial origin are presentbut have rarely been identified. The relationshipbetween these glacialdeposits is not known indetail. However, it is usuallyonly within theburied valleys that thick complexes of sand, silt andclay occur. Where thedrift is thin, till is generallythe only deposit.

Inthis area, as inother glaciated lowland regions, the rockhead or bedrocksurface has a morepronounced topography, or higherrelief index, than thepresent surface (Fig. 6). Pre-existingvalleys grade to below sea level andhave been infilled by glacial drift. Boreholes prove three major buried valleys, two of which inthe north decline N and E tolevels below OD. The northernflank of a thirdvalley,which lies beneaththe Ouse Burn, occurs on

thesouthern margin of the district.

Highestbedrock elevations, where the drift is also thin,usually

coincidewith the outcrops of more massive,relatively coarse-grained

sandstonesand generally form linear knolls (eg Brenkley, Killingworth and 23

\

/?

1 - 1 Alluvium ( includinglacustrine alluvium )

0 1 2 3 4 km I * 1 Glacial Sandand Grave! 1 I 1 t I I SCALE 1 0 1 Till, ( Boulder Clay) an.d Glacial Drift undifferentiated

Solid rock at surface

Fig. 5 Quaternary deposits 3 al

70

Contours indicate level in metres aboveO.D.; Solid rock at surface values on high side of line. The contours shown relateonly to natural 0 1 2 3 4 km rockhead surface and do not take into account 1 1 I I I opencast coal excavations. SCALE

Fig. 6 Rockhead elevation 25

0 8

70

lsopachytes at10 metre intervals; values on high Solid rock at surface kide of fine. The contours shown relate only to drift deposits and do not take into account opencast coal 0 1 2 3 4 km 1 I I I J excavations or made ground. SCALE

Fig. 7 Drift thickness contours 26

ShottonNorth Noor) rather than distinct ridges, Other than these, Coal

Xeasureslithology appears to have little influenceon rockhead relief,

The QOSt recentrockhead features are gorgescut since the last glaciation by theRiver Blyth and its tributaries Catraw Burnand Cascade

Dene.

Quaternary deposits

Till comprisesgrey-brown and grey, sandy, silty and pebbly clays

intercalatedwith thin lenses of sand, silt andgravel and overlain byabout

2m ofmottled orange, red-brown and pale grey silty, sandy clay with sporadic

small pebbles,These deposits mantle almost the whole district. The maximum

provedthickness of till is 46n butoutside the buried valleys thicknesses of

less than 10m are usual. Erratics are predominantly of Carboniferousrocks andinclude subrounded clasts of sandstone,siltstone, mudstone, ironstone,

limestone and coal, A fewfar-travelled fragments of igneous and metamorphic

rocksalso occur. The erratics rangein size fromsand toboulders, with the

latterincreasing in abundance towards rockhead,

The greyand grey-brown till is largely an over-consolidatedlodgement

till deposited by a singlephase of glaciation during the Devensian. The uppermostred-brown clays have been variously interpreted as upperlodgement

till, ablation or flow till, a product of gelifluction(i,e. periglacial

freeze/thawmudflow) or, more recently, as a post-glacialweathering profile.

It is likelythat morethan one process contributed,

Glacial Sand and Gravel withinthe glacial sequence is proved in aJnmber of

boreholes,but crops out over only about lkm2 inthe north-west at

Stannington, W ofBlagdon Hall and inthe north-east at East Hartford,There

are no workingor disused sand and gravel quarries nor any significant natural

exposures, thus thedetailed lateral and verticalrelationships are not 27

known. Boreholerecords indicate that sand and gravel is largelyconfined to theburied valleys, in generally thin and laterally impersistent lenses, and not in a singlecorrelatable unit.

Individualbeds range up to a maximum provedthickness of 10.36m in a boreholenear Horton Bridge [278 7921; butgenerally thicknesses do not exceed

3m. The depositsappear to bepredominantly of sand-grade although many boreholerecords are ofdubious quality.

Burnett 6 Eylesin the 1930's resurveyinterpreted the intraformational sandand gravel as the addle Sands of a tripartite UpperBoulder Clay-Middle

Sands-Lower 3oulderClay sequence, implying a re-advanceof the ice sheet followingdeposition of the sand and gravel. Later information from boreholes andopencast sites, and research into similar depositselsewhere, has shown thatthe drift sequence is morecomplex and thatauch of the sand and gravel may havebeen deposited sub-glacially.

Laminated silt and clay. Althoughnot recognised at outcrop,relatively stone-free,evenly bedded silts and clay are provedwithin the drift, particularlyin boreholes in the West Xoorand Dudley areas. The claysand silts occurwithin a complexof till, sandand gravel and attain a maximum provedthickness of 4.lm. Laminatedclays may be mre widespreadbut lack of detail in mostborehole records precludes detailed assessnent,

Alluvium. Thindeposits of clay, silt andfine sand fringe the rivers and streams andinfill hollows and depressions. On theeastern margin of

Prestwick Carr [203 7381 finealluvial peaty sands =lay havebeen redistributed

by wind, 27

Peat occurs at Trestwick Carr and locallywithin alluvium. 28

MINERAL RESOURCES

Coal, The onlycurrent mining is at Brenkleycolliery [222 7431, where the Topand Bottom Busty seams are worked.Large-scale aining ceased with the closure of a successionof collieries in the 1950's and 1960's.

Substantialquantities of coalremain, particularly in areas offormer pillarand stall working, in isolated patches cut off by faults or other geologicalstructures, in barriers between takes (colliery working areas) and inthinner seams at significantdepths beneath the surface. Rowever, with the exception of Brenkleycolliery, it is likelythat no furtherdeep mining will take place. Geologicalconditions and the extent of foner workings will favouropencast extraction of remainingresources.

Opencastcoal quarrying began in 1942, reaching a peakin the late

1940*s, andrestored opencast sites abound inthe north and west (Fig 8).

Xiththe exception of the Rensham all the named seams fros theBottom Busty to the Ryhope Little havebeen worked. Only Brenkley opencast site [206 7471 workingthe Plessey seam is currentlyactive, but a small licensed site at

Stickley Farm [ 281 7751 workingthe Xoorland and associated thin seam closed in 1984. Extensive areas havebeen prospected by the NCB OpencastExecutive, althoughseveral prospects have already been sterilized by industrial or domesticdevelopment. In the eastsrn part of the area thsre may bepotential foropencast working of small sites inthe higher seams, €or examplethe

Ryhope Little which was worked in 1970 at Havelock 1292 7391.

\ 2

Sandstone. Themore aassiveand relatively coarser-grained sandstones havebeen worked forbuilding stone from numerous small quarriesthroughout the area, butthese are all now closedand mosthave been reclaiaed or 29

partiallyinfilled. The qualityof the stone aay bejudged from local buildings.Resources are vast,but no stonein this area hasestablished a widereputation.

Shale and mudstone. Thickmudstone and siltstone above the Plessey Seam west ofBrenkley [204 7471 were recentlyworked for brick-making. Resources of mudstone are veryextensive, but there is noinformation on quality.

Metalliferous minerals. Veinswith pyrite, galena, sphalerite, calcite, ankeriteand baryte occur throughout the area butrarely exceed 2mm inwidth and so are ofno commercial interest.

Intrusive igneous rocks. Tholeiiticdolerite south-east of Stannington was quarried [ 2237881 on a mall scale in thepast, probably for road metal.

As thedyke is less than 2m wide, it is of no comercia1interest today.

Sandand gravel. There is nocommercial extraction of sandand gravel, though it was formerlydug on a small scale south of YiddleBrunton East Farm

[2287031. Significant thicknesses of sand and gravelbeneath relatively thin overburdenhave been proved in the Ouse Burn valley, near Horton Bridge and south-east of Stannington [2177871. At thelast-named locality the possibilityof opening a borrow pit forsand for use during road construction hasbeen investigated. Glacial sands and gravels show relativelyrapid lateraland vertical changes in grade, but in this areasand predominates, though it is usuallyfiae andwith clayey and pebbly layers.

\ d

Glacial clays (chieflytill) have been workd for brick making inthe pastfrom snall pits throughout the area. Recentlyclays have been workedon a larger scale at two sites, south-east of BurradonHouse [280 7271 and betweenSeghill and Backworth [ 293 7331. 30

Peat. There is norecord of peathaving been cut from that part of

Prestwick Carr within the area.

Groundwater is notabstracted for public supply or industrialpurposes,

apart from mine dewatering.Ubiquitous old workings and the disturbance to

thenatural regime they cause, local undesirably high concentrations of iron

andchlorides, the inperneable cover of boulder clay and the sealingeffect of

built-up areas all combine tonake appreciable quantities of potable

groundwaterunobtainable. Large areas ofbackfilled opencast sites

effectively seal offthe underlying outcrop from surfacerecharge. Thus

undergroundworkings become dry after the same seam up-dip has beenremoved

opencast .

Barium salts were formerlyextracted from groundwater at Backworth

Colliery, and relativelyhigh concentrations of calcium, bariumand chloride

are alsorecorded by Anderson (1945) ingroundwaters at othermines.

GEOLOGICAL IMPLICATIONS FOR LAND-USE PLANNING

Coal mining

East of theoutcrop of the Beaumontcoal (Fig. 3), practicallythe whole

area hasbeen underzined by workingsin one or more coal seam. Workings

within 30m of thesurface are shown inthe shallow coal workings map. There

are restricted areas ofwctrkings north-west of Brenkley i2 the Top andBottom

Bustyand at Stanningtonin the Victoria. All the named coal seams from the

High Nain toVictoria (Fig. 2) exceptthe Bentinck and Hodge havebeen

exploited somewhere withinthe area andseveral of the thick~rseams havebeen

workedout almost conpletely. Local workings are known in the Ryhope Five

Quarter west ofBackworth but in generalcoals above the Yigh Mainhave not 31

beenmined. Details of individual seams are givenin the stratigraphical section of thisreport.

The earliest workingsin the area forwhich plans are availabledate from about 1850 and were inthe Northumberland Low Main,Yard and High Xain seams.

However,mining of these and other seams nearoutcrop in areas of thin drift was active at least as early as themid-17th century, if not earlier. Early workings were by bell pits and pillarand stall workings;subsequently long-wallpanel working was introduced,giving a highlevel of extraction.

Themajor constraint of coal mining on planning and engineering arises from thepossibility ofsubsidence, either associated with new workings,or as the resultof collapse (or further collapse) of existingworkings.

Currentextraction andconsequent subsidence are takingplace only in the west inworkings from Brenkley colliery. Subsidence associated with modern miningmethods takes place contemporaneously with extraction of the coal, and althoughdramatic in the short tern cangenerally be considered to have ceased fen yearsafter working. The area of standing water eastof Arcot Hall [251

7531 and the markedNW-trending lineardepressions W of Hoys Wood [223 7561 NE of Brenkley are typical ofsubsidence features related to recent longwall miningin the Busty seams.

Delayedsubsidence takes place by the upward migration of voidsowing to collapse of pillars or of strata bridgesfollowing pillar and stall work, or less cornorsly by furtherconpaction of the collapsed workings which result fromlongwall working or total extraction. ?lost of the mining in the deeper seam inthe south and east of thedistrict, which has taken place since about

1940, was by neans of longwallworking and is notconsidered to pose a serious subsidenceproblem. Shallow workings less than 30m ar so belowsurface, particularly pillar and stall workings, are likely to causethe most damaging subsidenceand may belongest delayed. With the exception of the Brenkley colliery area, practically all occurrencesof pitfalls or other mining-related subsidencefeatures fall within this 3Om zone. Known orpossible shallow 32

workings are shown inthe shallow coal workings map. The areas delineated are generalizedand in considering particular sites it is usefulto consult originaldocuments. Workings known frommine plans can be anticipated and takeninto account when planning,but areas ofprobable or possibleworking are much less predictable.Evidence for shallow mining in areas notrecorded onplans is derivedfrom boreholes, features such as pitfalls and the discoveryof old workings in opencast or other excavations. 4ncient unrecordedworkings may occurin any areas wherecoal seams thickenough to be worked lie nearthe surface.

Areas of pitfalls,circular depressions commonly two tofour metres in diameterwhich often fom rectilinear patterns, resulting from the collapse of pillar and stall workings, were identifiedduring the survey near the outcrops ofthe Northumberland Low Main,Yard, Netal andFive quarter seams and are notedon the geological naps. Typical examples can be seen near East Hartford

[262 7901 and east ofBrenkley [229 7523. Some areas of pitfallshave been filledwith ash or colliery waste, forexample south-east of Dinnington E212

7311. Few definiteexamples of bellpits were observedbut wherever coal is exposedor under very thin drift it shouldbe assumed tohave 'Seenworked.

?lineshafts are presentthroughout the area and are particularly numerous betweenCramlington and the River i3lyth. The sites of all shafts and adits known tothe National Coal Board are shown on thegeological maps,but others my also exist. The positionsof many oldshafts are verypoorly documented and, as they were comonlyonly capped at surfacelevel and remain open below, still present a hazard. The conditionof shafts and adits needs investigation,in consultation with the NCB, before any developnenttakes

place. d\

Geotechnical properties

Areas inwhich the drift thickness is less than Sn, wherefoundations or

trenches for servicesnay encounter solid, are delineated on the 1:10 000 33

driftthickness overlays.

Mudstones and siltstones togethercomprise the bulk of the Coal Yeasures, but

they are generallycovered by thickdrift. Their clay minerals are stable,

butmudstones weather rapidly on exposure; even when covered by a substantial

thicknessof drift, the topnost 1 to 3 metres are generallyweathered.

Trenching is relativelyeasy but tunnelling at depths of 12m or less presents

substantialsupport problems. Explosives are notgenerally required in

surfaceexcavations.

Sandstones. Excavationand tunnelling in sandstones presents few support

problemsbut generally requires explosives for depths below 2 to 3n. Some of

thecoarser-grained sandstones are gritty andhighly abrasive and some

sandstones are quartz-cementedand extremely tough. Ganister, a varietyof

sandstoneseatearth found beneath some coals, is a particularlytough rock.

Jointblocks that have been weakenedby subsidenceover old coal workings nay

requiresupport in deep excavations and the presence of deep open joints may

necessitatespecial precautions.

Seatearths containreadily-weathered clay minerals which with the abundant

random internalpolished ('listric') surfaces make them unstableboth in excavationsand under load.

Till orboulder clay whichmantles much ofthe area is a toughover-

consolidatedlodgement till. Typicalundrained shear strengths are in the

range 103-350 kN/m2 and it is generallyregarded as a good foundationmaterial

whichpresents few problems in trenching, tunnelling and in excavations except

for its toughnessand the presence of bouldersand potentially waterbearing

sandand gravel bodies.

The reddish-brownand brown stonyclaysforming the uppermost 1 to 2m of 34

theglacial sequence however possess quite different geotechnical properties and are inherentlyweaker than the subjacent sediments, They are characterised by increasednatural moisture content, increased plasticity, increaseddrained brittleness and a reductionin undisturbed undrained shear strength.The last named is locallyincreased where the clays are dry or wheresecondary effects have led to unusual compaction, but lower parts of the deposits are commonly soft and plastic where incontact with underlying water-bearing strata. The reversedstrength gradient thus induced must be takenfully into account in foundation design, but is anespecial hazard in openexcavations which are reasonablystable where the clays are drybut dangerouslyunstable where lower parts ofthe profile are wet; the sub-verticaljoints are a majorsource of weakness insuch situations and also lead to instability onnatural slopes especially where superficial stony clay overliesplastic laminated clay,

Othertypes of till (flowand ablation) may bepresent but their distribution andgeotechnical properties are difficultto predict.

Laminated Silt and Clay, thoughsubordinate in aaount within the glacial sequence, are significantbecause of their engineering characteristics, Below the water tablethey are generally weak,with a shear strength commonly rangingfrom 25 to 70 k!V/rn2. Under verticalload the clays are prone to strongconpression and ductile flow, and foundations need to be specially designed: slab foundations or pilingto rock orinto strong till is generally necessaryfor heavy structures. Laminated clay and silt has a low safeangle ofrest and excavations need close support; tunnelling and shaft sinking are moderatelyhazardous wherp these deposits are drybut call forextreme care wherethey are water-bearingand therefore highly prone to fluidization and ductileflow. Digging main sewer trenchesin these deposits proved difficult in places. 35

Glacial Sandand Gravel. Water-bearingsands and gravels encountered within till sequences may be a problembut elsewhere sand and gravel, where dry or confined,can support considerable loads.

Alluvium,Lacustrine Alluvium and Peat. Alluvium is generallythin and where sandy will posefew civilengineering difficulties. However, silt, peatand organicclays, which are generallypresent, give rise tofoundation problems.

Landslips havebeen recorded where slopes have been oversteepened and undercut by theRiver Blyth, especially where thick drift deposits infill the buriedvalley south of Stannington.Slipping is a potentialhazard wherever slopescut into interbedded clays, silts andsands are oversteepenedeither artificiallyor naturally, Lubrication of potentialslip planes by groundwater will give rise togravitational and rotational slips.

Made ground and backfilledopencast coverabout 10% ofthe area (Fig 8).

Colliery spoil makesup most of the made ground and several old spoil heaps are still obviouslydistinct artificial mounds.However, duringreclamation the spoil is commonly redistributedover a wider area, dressedwith soil and plantedwith grass or trees, In suchlandscaped areas the extent and thicknessof made ground is difficultto fix precisely; for example landscaping of thespoil heap north of Seghill 289 752 , involvedremoving topsoilfrom approximately 0.5h ofthe neighbouring fields, spreading colliery waste andthen re-soiling -- inthe absence of otherinformation the new surface of thefields might be readily taken as thenatural one. The propoqtion of made groundcomposed of domestic or industrial refuse is snall. d

Xuchof theindustrial refuse comesfrom demolition of old buildings, and tips are usually less thanthree netres thick. Theonly extensive area of domestic waste is south-eastof Seghill 296 741 . It is importantto identify and nap made groundbecause of its differentfoundation properties, because of the 36

20 E A3*Q n Q

0 c Q

l4

I ...... __...... __.- : .% ...... _. .- ...... : ...... __-- ......

DV

7c

Worked out opencast coal seam area, Area of landscaping may extend beyond Other made ground (eg domestic or limits shown. - industrial waste, fill in old quarries)

Made ground associated with colliery workings (eg landscaped colliery spoil) Road or railway embankments are not shown. SCALE 0 1 2 3 4 km 1 I 1 I

Fig.8 Made ground 37

contrast in foundationconditions in passing from made tonatural ground, and because of theeffect on thedrainage of an area. Domesticrefuse, in particular, will containboth compressible and methane-generating components.

Inaddition to made groundspread on the surface, waste hasbeen tipped intoabandoned clay pits and sandstone quarries. Old clay pits occur throughoutthe area, andthough generally less than 10m indepth, can be quite extensive, as in the recently worked pitsouth-east of Burradon House [280

7271 , Sandstonequarries are generally small in area, butcan exceed 1Om in depth. The fill ofthese old excavations will behighly variable and may includedomestic waste; compactionof the fill leading to differential settlementof any structure built across the edges of theexcavations is a particularhazard. Known pits andquarries are shownon the geological maps, butthere may beothers, for example small sandstonequarries in areas where rock is exposedor has only very thin drift cover,

Backfilledopencast coal sites are extensiveand numerous in the western part of the area with a few sites inthe east; oneof the largest sites, Delhi

[2087601, workedseven seams overan area of 47 hectares to a maximum depth of 40m. Dates ofthe completion of coaling are given for each site on the geological maps.Opencast quarries are filledwith the overburden which was originallytaken from them, Although settlement and compaction of the fill mustbe expected in the years immediately following restoration,the position andformer depth of the excavations is well known andbecause of this they can betaken into account in planningand implementation of engineeringworks. In the east two sites, Shankhouse [2727741, andCramlington [249 7681 havebeen builtover with housing estates. 38

CONCLUSIONS

1. Extensivecoal mining places restraints on planning or development,

especially in areas where coal hasbeen mined at shallow depth.

Subsidenceassociated with the collapse of oldworkings is likely to be

greatestover areas ofancient pillar and stall workings, many ofwhich

are unrecorded.There are numerous shafts, many of which are poorly

docmented, Many shafts are notfilled and may bepoorly sealed.

2. Subsidencemust be anticipated above present and future workings from

Brenkleycolliery.

3. The till whichcovers much of the area generallyprovides good foundation

conditions,however the complex drift deposits of theburied valleys have

more variableand relatively weaker engineering properties. Steep slopes

in thicker and morecomplex drift will fail if overloaded or

over-steepened.

>ladeground, particularly that filling old quarries, poses problems of

unevensettlement, especially for structures across the margins.

Backfilledopencast coal sites are numerousbut their position and forner

depth is usually well documented.

5. The area containssubstantial resources of coal which could be extracted

by opencastmethods.

6. Resourcesof sand and gravel are restrictedto three localities: in the

OuseBurn valley,near Horton Bridge and south-east of Stannington. The

material is predominantly of finegrade. Its potentialfor use as fill

duringroad construction has beeninvestigated south-east of Stannington.

Sandstonehas been quarried locally for building stone, and there are

ampleresources.

Apartperhaps for areas ofnear-crop coal which might be exploited

opencast,there is no reasonto recommend anymeasures to prevent

sterilization of aineral resources. 39

SELECTED BIBLIOGRAPHP

ANDERSON, W. 1945. On thechloride waters of Great Britain. Geot.

Mag., Vol. 82, 267-73.

ANSON, W.W. and SHARP, J.I. 1960. Surfaceand rock-head relief features in

thenorthern part of theNorthumberland Coalfield. Urliversity of

Newcastle upon Tyne, Dept. of Geography,Reseurch Series No. 2.

BEAUMONT, P. 1968. A history of glacialresearch in northern from

1860 tothe present day. Uniu. Durham OCC. Papers, No. 9.

BORINGS AND SINKINGS. 1878-1910.Council of theNorth of England Institute

of Miningand Hechanical Engineers, An account of the strata of

Northumberland and Durham as proved by brings and sixkings. 7 vols in 4 books . Newcastleupon Tyne. EYELES, N. and SLADEN, J.A., 1981.Stratigraphy and geotechnical properties

of weatheredlodgement till in Northumberland,England. &.J.Eng.GeoZ.

Vole 14,129-141.

HURST, T.G. 1860. On some peculiaritiesof the Tyne Low %in Seam. Tra~s.N.

Engl. Inst. Min. Eng. Vol. 8, 23-31.

LAND, D.H. 1974.Geology of the Tynemouth District. Mem. CeoZ. Surv. G.B.,

Sheet15

ORCHARD, R.J. 1964. Partialextraction and subsidence. Trans. Inst. Mine

Eng., Vol. 123,417-427.

PIGGOTT, R.J. and EYNON, P. 1978.Ground movements arisingfrom the presence

of shallowabandoned mine workings. In GEDDES, J.D. Largeground

novementsand structures. Proceedings of theConference held at the

University of Wales Iristitute of Scier,ce and TechnoZogy, Cardiff1977.

Pentech Press London,749-783. \

TAYLOR, B.J., BURGESS, LC., LAND, D.H., MILLS, D.A.C., SXITH, D.B. and

WARREN, P.T. 1971.Northern England. Brit. Reg. CeoZ. (4thEdit) HXSO

forInst. Geol. Sci.

TAYLOR, R.K. 1967. Siteinvestigations in coalfields; the problem of shallow 40

nineworkings. Q.J.Eng.CeoZ., Vol. 1, 115-133.

WOOLACOTT, D. 1905. The superficialdeposits and pre-glacial valleys of the

Northumberlandand Durham Coalfield. &.JnZ.CeoZ.Soc.Lond., ~01,61,

64-96,

The memoirby Land (1974) shouldbe consulted for furtherreferences.