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UrbanGeologyinLondonNo.36
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Afire-spittingvolcanoinDeptford?UrbanGeologyinSoutheastLondon
RuthSiddall
No,therearenovolcanoesinDeptford,andtherehaveprobablyneverbeenanythroughoutatleastthelast1000millionyears.ThetitleofthisurbangeologicalwalkcomesfromanobservationofanastonishedandbewilderedresidentoftheGleichburginGermanywhomay(ormaynot)havewitnessedavolcaniceruptionthereinthe18thCentury(seeGrattanetal.,2000).InFebruary2017,SmashFestUKcelebratedvolcanoesandallthingsvolcanicintheircommunitysciencefestivalbasedinDeptford,southeastLondon.Partofthiseventincludedageologicaltourofthearea’s(mainly)igneousrocks,usedaspaving,streetfurnitureandbuildingmaterials.Thisisawriteupofthattourwiththeadditionsofafewotherlocalbuildingsworthyofgeologicalinterest.ThewalkstartsattheAlbanyTheatreonDouglasWay,SE84AG.FromthemainentranceofTheAlbany,turnleftandthenleftagaincrossingthemarketplaceintoDeptfordMarketYard.DeptfordMarketYardTheredevelopmentofDeptford’sMarketYardandtheimpressiveVictorianCarriageRampwasundertakenbyFarrerHuxleyAssociatesin2015.TheRampitselfwasdesignedandbuiltfrombrickbyColonelGeorgeThomasLandmann(1780-1854)oftheRoyalEngineersin1835.TheLondon&GreenwichRailwaywasLondon’sfirstrailwayline,openingin1836andpassengerswerecarriedonanelevatedline,hencetherequirementforanaccessramp.ThelineranfromGreenwichtoLondonBridge,andDeptfordwasthefirststop.The2015redevelopmenthasplacedshopsandcafésintheRamp’sarchesandhaspavedtheYardtomakeaverypleasantplaceforsocialisingonthewaytoandfromthestation.TheMarketYardhasbeenpavedwitharangeofChinesegranitesandrelatedrockswhichareverypopularforcitypavingatpresent;mainlybecausetheyareavailableinlargequantitiesandarerelativelycheap,whilstbeinghard-wearingandattractive.Granitesareigneousrocks;thosethathavecrystallisedfromthesolidificationofameltand
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canformcanforminmanyenvironmentswithintheEarth’scrust.Theyare‘Plutonic’rocksratherthan‘Volcanic’.NamedaftertheGreekgodoftheunderworld,Pluto,granitescrystallisefroma‘magma’underground,usuallyatdepthsof5ormorekilometres.Somegranitescanoccuratmuchshallowerdepthsandthesecanbethemagmachambersthatfeedvolcanoesandarethesourceof‘lava’whichisliquidontheEarth’ssurfacebeforeitfreezes.Asarocktype,a‘granite’isdescribedasbeingaplutonicigneousrockcomposedofthemineralsquartz,micaandfeldspar.Allgranitesbydefinitionhavethisbasicrecipe,butlikeice-creams,theycancomeinallkindsofdifferentflavours.Tracemineralsandelementscanalterthecolourofthemajormineralsandgrainsizeandshapecanvary.AlthoughastonemasonwouldcallallthestonesusedhereinDeptfordMarketYard‘granites’,geologicallywehaveherethreegranitesandarockcalledadiorite.Luckilytheyarealleasytodistinguishtoo,beingdifferentcolours.
LuoyuanGranite(topleft)haslargepinkandwhitefeldsparcrystalsaswellasquartzandablackvarietyofmica(biotite).ItisfromFujianProvinceinSEChina.Ithasanoverallpinkappearanceandisaverystrikingstone.ShandongRustGraniteisayellow-browngranitewhichgetsitsnamefromrustyspots,stripesandpatchesthroughoutthisrockswhichhavegivenanotherwisewhitegraniteayellowtorusty-browncolour.Therustisduetoironwhichhaspercolatedthroughthegraniteasithasbecomeweathered.LaizhouGranite(belowleft)isaratherunusuallookinggranite,withamedium-grained,greygroundmassmadeupofthethreemaingraniteminerals,quartz,micaandfeldspar.Howeveritisscatteredwithlargercrystals,2-3cmlong,ofwhiteandpink,well-shaped,feldsparcrystals.Someofthepinkcrystalshavewhiterims.Thecolourchangesrepresentsubtlechangesinchemistryasthemeltwascrystallising.Itiseasytomistaketheselargercrystalsforchewinggumonthepavement,butthenamefortheselargecrystalsinafinegrainedgroundmassisphenocrysts.ZhangpuGreenGraniteistheoddoneouthere,itisadiorite,anigneousrockcomposedoffeldspar,whichisusuallywhiteorgreyandadarkgreenmineralcalledhornblende,andthisiswhythisstoneasagrey-greencolour.Ithascrystallisedfromameltofadifferentchemistryfromthatofgranites.However,tostonecontractors,prettymuchalligneousrocksare‘granites’.
ZhangpuGreencomesfromFujianProvinceonthecoastofsouthernChina.Luoyuan,LaizhouandShandongGranitescomefromShandongProvinceonthecoastofsoutheastChina.AllwereintrudedduringtheMesozoicera,partofthegeologicaltimescalethatcomprisestheTriassic,JurassicandCretaceousPeriods,thetimeofthedinosaurs!ThiswasthetimethatthelandmassthatisnowsouthandeastChinawasbeingformedbyplatetectonicprocesses.TheSouthChinaSeawasbeingforcedundertheAsiancontinentalcrustbuildingmountainsalongthenewcoastlines.DuringtheMesozoic,thispartofSEAsiawouldhavebeenliketheAndeanMountainsofSouthAmericatoday–highmountainsandlotsofvolcanoes.Thegranitesanddioriteswehaveseenherewouldhavebeentheplumbing,feedingmagmatothevolcanoeswhereitcouldbeeruptedaslavasandvolcanicash.
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OnleavingDeptfordMarketYard,turnleftalongDeptfordHighStreet.AsmallpieceofevidenceofEnglishmagmatismcanbefoundonthecanbespottedonthekerb.FfinchStreetAVictoriankerbstonemadeofCornishGranitesurvivesamongsttheconcreteonthecornerofFfinchStreetandDeptfordHighStreet(below).TheCornishgranitesdidnotfeedvolcanoes,buttheydidproducespectacularrockswhichwerewidelyusedasbuildingstonesthroughoutthe19thCentury.
Thewhite,brick-shapedcrystalsarethemineralfeldspar,oneoftheessentialcomponentsofthegraniterecipe.Thecrystalshereshowsomealignment.Peopleoncebelievedthatthisalignmentwasduetothesolidcrystalsflowinginaliquidmelt.Howevermoltengraniteisextremelyviscous,somuchsothatwewouldnotthinkofitasaliquid.Ithasaconsistencymorelikepeanutbutter.Wenowbelievethatthesephenocrystsformedlaterinthecrystallisationhistoryofthegraniteandanyalignmentthatweseeisprobablymorelikelytoberelatedtodeformationoftherockratherthanflow.Ifyouwanttoseesomefossils,thentakeashortdiversiondowntoStPaul’sChurch.StPaul’sChurchStPaul’sisafineBaroquechurch,designedbyarchitectThomasArcherandcompletedin1730(seeCherry&Pevsner,2002).Ithasasemi-circularportico,supportedbycolumnsatthefrontentranceandporchesaccessedbystaircasesonthenorthandsouthsides.Geologicallywemustnowtakeadetourawayfromourigneousrocksandtheirassociationswithvolcanoes,forthechurchisbuiltfromLondon’smostfamousbuildingstone,PortlandStone.The17thcenturyarchitectInigoJoneswasinfluentialinbringingPortlandStonetoLondon.HeusedittobuildtheRoyalBanquetingHouseontheMallin1620.AftertheGreatFireofLondonin1666,useofPortlandStonetookoffanditwasusedbyChristopherWrentorebuildStPaul’sCathedral.FromthenonitbecameLondon’smainbuildingstoneanditwasoftenusedforcivicbuildingsandchurches.PortlandStoneisapale-greylimestoneoflatestJurassicage,deposited145millionyearsagoinwarm,shallow,tropicalseas,fulloflife.Evidenceofthiscanbeseeninthefossilshellsthatareeasilyspottedinthisstone.Giventhisbuildingisnearly300yearsold,thePortlandStonehasweathered,andtheharder
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fossilsnowstandproudofthesurface.Theseareoystershellsandthelaminatedstructureoftheirshellshasbeenwellpreserved.ThepresenceofthesefossilstellsusthatthisisthevarietyofPortlandStoneknownasWhitbed.
FossilsinthestonesofStPaul’sChurch.Topleftandright,PortlandWhitbedwithfossiloystershellfragmentsweatheringproudofthesurface.Bottomleftandright,varietiesofPurbeckStonewithvariousfossilisedfreshwatershellsandalgae.PurbeckStoneisEngland’s‘marble’.Itisnotatruemarbleinthegeologicalsensebutitisanarchitecturalmarbleinthesensethatitisalimestonethattakesagoodpolish.Itwasverypopularinecclesiasticaldecorations.IntheexteriorofStPauls,weseeitaspavingonthenorthandsouthsideporches,whichareaccessedbysymmetricalstaircases.Theseareasarepavedwithared,sandylimestonecalledMansfieldRed,fromNottinghamshire,PortlandStoneandthevarietiesofPurbeckstonewhichareillustratedabove.GeologicallythePurbeckBedsoverlythePortlandStone,markingnotonlyamajorchangefrommarinetofreshwaterenvironments,butalsothechangefromtheJurassictotheCretaceousera.Thefossilsindicatethischangeinenvironmentwithfreshwatersnailsandmusselstakingtheplaceoftheseashellfossilsfound
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inthePortlandStone.PurbeckStonehasalsorevealedrarefossilsofreptileboneandinsectsaswellasoccasionaldinosaurfootprints.PurbeckhasbeenquarriedsincetheRomanperiodfromquarriesaroundthevillageofLangtonMatraversontheIsleofPurbeckinDorset.Thebedsarethinandthereisalotofvariabilityintheappearanceofthevariousstonesand‘marbles’extractedfromthesestrata.LeavethechurchyardandturnleftbackontoDeptfordHighStreet.RetraceyoustepsbacktothestationandTomi’sKitchenoppositethestationendofDeptfordMarketYard.Tomi’sKitchenTomi’sKitchenRestaurantat126,DeptfordHighStreetusedtobeapub,TheMechanicsArms1,andithasverytypicalstoneworkforaLondonPub(seeSiddall,2014).Pubswereintendedtolooksmartandclassy,butnottooclassy!NofancymarblesinLondon’spubs.ThestoneofchoicewasacolourfulgraniteusuallyfromScotlandorScandinavia.HereatTomi’sKitchenwehavered,ScandinaviangranitesandinfactbothhereareoriginallyfromtheeastcoastofSweden.LiketheoneswehaveseenaboveintheMarketYard,theyhavethestandardquartz+feldspar+micarecipe.ThetwovarietiesareSwedishBalmoralGranite(belowleft)andGraversforsGranite(belowright).
Bothgranitescontainbrick-redfeldsparsandtheblackmica,biotite.ThewhitemineralinSwedishBalmoralGraniteisquartz,andthisgivesthegraniteared-and-whiteappearancethatcanbeseeninthephotographabove.GraversforsGraniteontherightismoreofapurplecolouroverall,andthisisdowntothequartzbeingalmostvioletincolour,partlyduetothefactithasbeencrushedandalsobecausethereisalotofironoxide(themineralhematite)inthistoo.Theseareextremelyancientrocks,almosttwobillionyearsold(1800millionyearsold).ThesearecertainlytheoldestthingsonDeptfordHighStreet!ContinuedowntheHighStreettoGiffinStreet.GiffinStreetHereintheplazaonGiffinStreet,wegettoseesolidifiedlavaflowsinDeptford.Thisstoneisusedforthecubeseatingblocksintheplaza.ThisisanotherChinesestonecalledBlackPearlBasalt.Abasaltisavolcanicigneousrock.Basaltsarecomposedofthedarkcolouredmineralsolivine,pyroxeneandavarietyoffeldsparandareconsequentlyblackincolour.Thesebasaltswereeruptedasenormouslavaflows,fiftymetresthick,duringtheCretaceous,around140millionyearsago.Theseeruptionswouldhavebeen
1 TheLostPubsProject:http://www.closedpubs.co.uk/london/se8_deptford_mechanicsarms.html
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unimaginablyhuge,nothinglikethemhasbeenseeninhumanhistory.ThegraniteswehaveseeninDeptfordMarketYardandtheirrelatives,wouldhavebeenthemagmasfeedingtheseenormousvolcanoeswhicharetruesupervolcanoes.Therecraterswouldhavebeen50milesacrossandmostoftheeruptiveproductswouldhavebeenvolcanicashandpyroclasticflows.Basaltswereonlyasmallproportionmaterialerupted.Howeverthesolidifiedflowsarestillenormous,formingcolumns(whicharetypicalofthickbasaltflows)whichcanbeseeninthequarriesinBailininFujianProvince.Thesecolumnsformasthelavacoolsandsolidifies,andareupto2-3metresdiameter(seebelow,right).Asaresult,largeblockswithnocrackswithinthemcanbeproduced.
Aboveleft;theporphyrybasaltatGiffinStreet.Right;TheBlackPearlquarriesinFujianProvince,China(photofromStoneContacthttp://www.stonecontact.com/quarries-2209/china-black-basalt-quarry).Lookingcloselyatthepolishedsurfacesoftheblocksandyoucanseethattheycontainblackspots.Thesearephenocrystsofthemineralpyroxene.Ifyoucanseeanygreencrystals,thesearethemineralolivine,sonamedbecauseitisolivegreen.Youcanalsoseethatthegroundmassisveryfine-grained.Thisvarietyoftextureinrocksiscalleda‘porphyry’.ContinuesouthalongDeptfordHighStreet.DeptfordHighStreetThegreenpavingcobblesaroundthejunctionwithGiffinStreetandDouglasWayareZhangpuGreenGranite.ThepatternofdifferentcolouredgranitesseeninDeptfordMarketYardisonceagainusedontheHighStreet;pinkisLuoyuanGranite,greyisLaizhouGraniteandthebrownisShandongRustGranite.
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ThelaststoponDeptfordHighStreetonthecornerofNewCrossRoadistheBroadwayRestaurant,ariotofgranites.BroadwayRestaurantOnthecornerofDeptfordHighStreetandDeptfordBroadway,TheBroadwayRestaurantalsohadaformerlifeasapub,TheCenturion2.Itisalsocladinavarietyofgranites,threeScottishandoneFinnish.PeterheadGraniteisthepalepinkgraniteusedformostofthesquaresectionpillarsbetweenthewindows.AsthenamesuggestitisfromPeterhead,afishingtownnorthofAberdeenontheeastcoastofScotland.IthassalmonpinkfeldsparsandsmokygreyquartzandlooksabitlikecoarseArdennespaté.Althoughnolongerquarriedtoday,thisstonewasverymuchinfashionduringtheVictorianandEdwardianperiodsandisusedtocladagreatmanypubsandusedasplinthsforstatuesetc.Itwasintrudedjustover400millionyearsagoduringtheformationofScotland’smountains.ThegreygranitepanelsbetweenthewindowsareCairngallGranitewhichalsocomesfromPeterhead,andthiswasquarriedclosetothepinkgranitequarriesatFlushing.Thequarriesarelongsinceclosedandarenowariflerange.CairngallGraniteismucholderthanPeterhead,at475millionyears.Justnextdoortothemainrestaurantat14,DeptfordHighStreetthebuildingschemecontinues.Atsometimeintherecenthistoryofthebuilding,therehasbeenneedtoreplacesomeofthePeterheadGranite,presumablybecauseitwasdamaged.Asitisnolongerworked,ithasbeenreplacedusingBalmoralGranitefromFinland.Thisgranitehascrystalsformingamosaicofbrick-redfeldsparsanddark-grey,almostblack,quartzisone-and-a-halfbillionyearsold.Itcomesfromthesouth-westcoastofFinland.
ThesmallpillarsoneachsideofthedooraremadefromDalbeattieGranitefromsouth-westScotlandalsoaround400millionyearsold.Thishaswhiteapalepinkfeldspars,blackbiotitemicaandgreyquartz.Thepillarnthelefthandsidehasadark-grey,raggedpatchinit.Thisisafeaturethatgeologistscalla‘xenolith’whichliterallymeansa‘strangerock’.Itisnotpartofthegranite,butpartofthepre-existingcountryrocksthatthemeltwasintrudedinto.Thereforeitisarockthatisolderthanthegranitethathasnotbeenincorporatedintoitandnotdissolvedintothegranitemagma(left).
ThisistheendofthemaintouroftheurbangeologyoftheareaaroundDeptfordHighStreet.HoweverifyouareheadingtowardsNewCross,thereareafewbuildingsworthyofgeologicalnotealongNewCrossRoad.InLondon’ssuburbs,mostbuildingisinbrick,butpubsandcivicbuildingsaregoodplacestospotsomegeology.TheNewCrossInnandNewCrossHouseareoppositeeachother,atthejunctiononNewCrossRoadandLewishamWay.NewCrossInnAnotherearly20thCenturypub,theNewCrossInnhasitsgroundfloorcladwithaScandinavianigneousrock.ThistimeitisfromthetownofLarvikinsouthernNorwayanditisnamedlarvikite.Larvikiteisnotagranitebecauseitdoesnotcontainanyquartz.Itisavarietyofrockcalledamonzonite.ItwasintrudeintotheOsloriftvalley(nowtheOsloFjord)around290MaduringthePermian.Larvikitehasbeenquarriedinacommercialscalesincethe1880sandasbecomeverypopularworldwideasastrong,hard-wearingandveryattractivestone.Itisfamousforitsiridescentfeldsparswhichshimmerandchangecolourasyou 2TheLostPubsProject:http://www.closedpubs.co.uk/london/se8_deptford_centurion.html
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moveyourhead;sometimesappearinggreyandsometimeselectricblue.Anumberofvarietiesofthisstonerangingincolourfromalmostblack,throughbluetogreyarequarried.ThisisthegreyvarietywhichgoesbythenameMarinaPearlLarvikite.Theimagebelowshowsthegrey,iridescentfeldspars.Theblackmineralsarebiotitemica(whichwehaveseeninsomeofthegranites)andpyroxene(whichwesawinthebasaltinGiffinPlace).
LarvikiteontheNewCrossInn.
WeknowthatthelarvikitemagmaschambersoftheOsloriftweredefinitelyfeedingvolcanoes.Weseetheproductsofthesevolcanoeswhichstillsurviveassolidifiedlavaflows,withverydistinctivediamond-shapedorrhombicfeldspars.Theserocksareknownasthe‘rhombporphyries’andtheyareavarietyoflavaswhichgeologistscalllatites.TheyareuniquetothePermianmagmatismoftheOslorift.Duringtheiceages,thesevolcanicandplutonicrockswereheavilyeroded(andthisprocesshelpedtoexposethelarvikiteintrusions).Chunksofrhombporphyrywerecarriedsouthbyglaciersandicesheetsanddumpedinmorainesandglacialsedimentswhentheicesheetsmelted.TheycannowbeenfoundintheglacialgravelsofSEEngland,andbecauseoftheiruniqueness,weknowexactlywheretheycamefrom.Thishasgivenuslotsofinformationabouthowfar,howfastandinwhatdirectiontheicesheetsmoved.
ApolishedslabofrhombporphyryfrozenlavaintheNationalMuseumofScotland.Thelargestcrystalsare1cmlong.PhotobyRuthSiddall.
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TheNewCrossHouseAcrosstheroadfromtheNewCrossInnistheNewCrossHouse.ThisiscladinBritishgranites;MerrivaleGranitefromDartmoorandCairngallGranitefromPeterheadinAberdeenshire,Scotland.WehaveseenCairngallearlieronTheBroadwayRestaurant.MerrivalecomesfromtheotherendoftheBritishIslesandisoneofthesuiteofgranitesintrudedintoDevonandCornwallaround300millionyearsago.Ithaslargewhitefeldsparphenocrystsandslightlybrownishquartz.Cornishgranitestypicallyhavetwotypesofmica;theblackbiotiteandasilveryvarietycalledmuscovite.Thiscanbeseensparklingintherock,especiallyifthesunisshining.MerrivaleGranitewasquarriedbytheprisonersincarceratedinDartmoorPrison.
StonesontheNewCrossHouse.Left;CairngallGraniteandright;MerrivaleGranite.
DeptfordTownHallLikeStPaul’sChurch,theoldDeptfordTownHallbuildingisconstructedofPortlandStone.TheintricatecarvingabovethemaindoorisenabledbyPortland’spropertiesasafreestone,thatis,astonewhichhasnopreferredweaknessandthereforecanbecarvedinanydirection.Asaconsequence,elaborateandintricatecarvings,asobservedinthisfishycoatofarms,representingDeptford’smaritimeassociations(below).ThebuildingwasdesignedbyarchitecturefirmLanchesterStewartPickardsandbuiltin1905.
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References
Cherry,B.&Pevsner,N.,2002,TheBuildingsofEngland:LondonNo.2,South.,YaleUniversityPress,Newhaven&London.,808pp.
Grattan,J.P.,Gilbertson,D.D.&Dill,A.,2000,AfirespittingvolcanoinourdearGermany?DocumentaryevidenceforalowintensityvolcaniceruptionoftheGleichbergin1783,in:McGuireW.G.,Griffiths,D.R.,Hancock,P.L.&Stewart,I.S.(Eds.)TheArchaeologyofGeologicalCatastrophes,SpecialPublications,GeologicalSocietyofLondon,171,307-315.
Siddall,R,2014,London’spubgeology:aspotter’sguide.,UrbanGeologyinLondonNo.20,18pp.,http://www.ucl.ac.uk/~ucfbrxs/Homepage/walks/PubGeology.pdf
Glossary
Basalt–avolcanicrockcomposedofthemineralsfeldspar,pyroxeneandolivine.
Diorite–aplutonicigneousrockcomposedfromthemineralsfeldsparandhornblende.
Freestone–arockwithnoplanesofweakness,meaningitisverygoodforthree-dimensionalcarving.
Granite–aplutonicigneousrockthatiscomposedoftherockformingmineralsquartz,feldsparandmica.
Igneous–atypeofrockthathasformedbythecrystallisation(freezing)ofasilicatemelt.
Lava–asilicatemeltontheEarth’ssurface,eruptedfromavolcano.
Magma–asilicatemeltwithintheEarth.
Mineral–asolidmaterialwithadefinedchemicalformula.
Phenocryst–alargecrystalinafinergrainedgroundmassinanigneousrock.
Plutonic–referringtoanigneousrockwhichhasformedwithintheEarth’scrust.
Porphyry–anigneousrockwithphenocrysts,whichthereforehasaspeckledappearance.
Pyroclasticflow–atorrentofrockfragmentsandashproducedbyaveryexplosivevolcaniceruption.
Rock–asolidmaterialmadeupofminerals.
Stonecontractor–thebusinessthatliaiseswithaquarrytosupplystoneattherequestofarchitects.
Volcanic–referringtoanigneousrockwhichhasbeeneruptedontotheEarth’ssurface.
IndexofStones
BalmoralGranite–BroadwayRestaurant(right)
BlackPearlBasalt–Giffinstreetsquare
CairngallGranite–BroadwayRestaurant,TheNewCrossHouse
CornishGranite–FfinchStreet
DalbeattieGranite–BroadwayRestaurant
GraversforsGranite–Tomi’sKitchen
LaizhouGranite–DeptfordMarketYard,HighStreet.
LincolnshireLimestone–StPaul’sHouse
LuoyuanGranite–DeptfordMarketYard,HighStreet.
MansfieldRed–StPaul’sChurch
MarinaPearlLarvikite–NewCrossInn
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MerrivaleGranite–TheNewCrossHouse
PeterheadGranite–BroadwayRestaurant
PortlandStone–StPaul’sChurch,DeptfordTownHall
PurbeckStone–StPaul’sChurch
ShandongRustGranite–DeptfordMarketYard,HighStreet.
SwedishBalmoralGranite–Tomi’sKitchen
ZhangpuGreenGranite–DeptfordMarketYard,HighStreet.
DeptfordMarketYardandCarriageRamp.
Howtocitethisarticle:Siddall,R,2017,Afire-spittingvolcanoinDeptford?UrbanGeologyinSoutheastLondon.,UrbanGeologyinLondonNo.36,11pp.,http://www.ucl.ac.uk/~ucfbrxs/Homepage/walks/Deptford.pdf
LocationsofthebuildingsdescribedaboveandbriefdetailsofthestonesusedcanalsobefoundintheLondonPavementGeologywebsite:http://londonpavementgeology.co.uk©DrRuthSiddall,UniversityCollegeLondon,GowerStreet,LondonWC1E6BT,UK:[email protected]
Downloadsfromhttp://www.ucl.ac.uk/~ucfbrxs/Homepage/UrbanGeology.htm;Facebook|Cultural&UrbanGeology|Twitter:@R_Siddall|#UrbanGeology