Stonehenge on Ice
STONEHENGE
Displayedwithpermission?The American Surveyor?July?Copyright2008ChevesMedia?
ON ICE THE STORY OF MAKING A FROZEN REPLICA
he idea to build a full scale replica of Stonehengeinice cameattheconvergenceoftwoevents in the middle of the hottest mid-summer July day in Fairbanks, Alaska. I was the chairman ofthe41stannualAlaskaSurveying andMappingConference(ASMC). Previouslytheconferencehadtaken placealmostexclusivelyinAlaska's largestcity,Anchorage,sinceits inauguralmeetingbackin1966.Only one other time had it been hosted at anotherAlaskacity,thelastonebeing inFairbanksin1987.Asincoming President of the Alaska Society of ProfessionalLandSurveyors(ASPLS) it was my responsibility to also chair theannualconferencein2007. Whatdobigcityfolksthinkof whenFairbankscomestomind?Cold andice:rivers,lakesandpondsofit. CleariceharvestedfromFairbanksareagravelpitsisconsideredsome oftheworld'sbestwhenitcomesto carving.Eachyearcarversfromthe worldover(mainlyfromsimilarly situatedcoldregionslikeRussia, Mongolia,Sweden,Norway,Poland, Germany, as well as less polar latitudes)convergeinFairbanksto carvelargeblocksoficeweighing severaltonsintoclearsculpturesin theWorldIceArtChampionship.
TheeventissponsoredbyIce Alaskaasoneofthefirstsignsof springtimeinAlaska'scentralinterior region.IceAlaska'sfrozenFairbanks festivaltakesplaceinMarch,the sametimeasoursurveyingand mappingconference.Wecontacted IceAlaska'sdirector,DickBrickley, onthehottestJulydayin2006to seeiftherewasinterestinmakinga replicaofStonehengeiniceasadraw forvisitors.Hewasexcitedtohaveus commissionalargecarvingofsucha scale that had not been done by them before.Soitwasdecidedovercool raspberry slushies on that hot summer daythatareproductionofStonehenge in ice would be built.
Wehadtofigureoutjustwhatit takes to layout and build a full scale mockupofamegalithicstructure. Stonehengebeganaround4,500 yearsago,constructedfromwooden posts,thenwasupgraded,modified andrevisedduringitslong13-centurydevelopment.Whatremains on the Salisbury plains of southern Englandtodayislessthanhalfof whatwasoncealargecomplexof stones, ditches, earthen mounds and causewayslinkedtoacivilization that had no metal tools to work with. Themajorityoftheconstructionwas accomplished by wooden hafted stone andboneimplementslaidoutusing knotted leather cords without the
>> By Martin Gutoski, LS
Displayedwithpermission?The American Surveyor?July?Copyright2008ChevesMedia?
A forklift places one of hundreds of ice blocks harvested in January from the gravel pit pond at Ice Alaska.
A handler maneuvers ice blocks into position for the forklift.
benefitofmuchelsebutlevers,pulleys andlogstoexcavate,shapeanderect morethan100monolithicpillarsupto 30feettallweighingnearly60tons.
The builders left behind no plans, somostoftheexplanationshavecome fromarchaeologicalstudiestoinferthe scenarios for possible methods used to build such an ancient complex. A recent concretereplicaofStonehengewas erectedatMaryhill,Washingtonafter WorldWarI,neartheOregonborder, buttheplanshadgonemissingsince thecountytookovertheoperationasa memorial to war dead.
TheInternetprovedtobeequallyuselesswhenitcomestoanythingasurveyor can use for layout, but a few hours at two of our local libraries netted some ancient tomeswithdescriptionsofStonehenge measurementsthatprovedhelpful.
Inigo Jones, Druids & Astronomers
The first measurements were made in 1615byInigoJones,Englisharchitect andSurveyorofWorkstoKingCharlesI. Hisfindings,however,werenotpublished until1655,whenInigo'sson-in-law
compiled the manuscripts to publish them posthumously in Latin, complete withfairlyprecisedimensionaloblique andplanviewrenderingsofwhatJones believedwasthemostlikelylayoutof Stonehengeinitsoriginalcondition. JonesattributedStonehengeconstructiontotheearlyRomanperiodof England'soccupation,somefifteen hundred years earlier.
Othersfollowedinthefootsteps ofInigoJones.In1640JohnAubrey attributedStonehengeconstruction to the Druids and contributed the bestmeasureddrawingsofthesite. TheOrdnanceSurveyof1867was thefirsttousetechniquesbyRoyal ArmyEngineerstogenerateaccurate surveymapsofthemonuments. Refinedmeasurementsdidnotappear until1958whenretiredprofessorof engineeringAlexanderThomand20 yearslaterRichardAtkinsonin1978 used modern theodolites to further the precisionofthedimensions.Bothmen were prompted by the assertions of astronomersGeraldHawkinsandFred HoylethatStonehengewasacomplex solar and lunar calendar.
High Noon on the Vernal Equinox
So which way should an ice replica of Stonehengebeoriented?Theoriginal wassetforEngland'smid-latitudeof51 degreesnorthatanazimuthofabout 24degreestocatchthesummersolstice sunrise.Thedeclinationangleofany celestialobjectvariesasafunctionofthe cosineoftheazimuthtimesthecosineof thelatitude.Fairbanks,Alaskaisat65 degreesnorthlatitudeand148degrees westlongitude.Summersolsticesunrise happenshardlyatalljustbelowtheArctic Circlesuchthatthesunbarelyskids belowthehorizonbeforeitpopsup afewdegreesfromtruenortharound localmidnight.
OrientingamodelofStonehengehere wouldmeanspinningitaroundsuchthat italmostbecomesacompasspointing duenorth.Iceheredoesn'tsurvivemuch beyondApril,sobythetimeIcehenge could point to summer solstice sunrise it wouldbeashimmeringpuddleofwater reflectingthemidnightsun.Sincetheice festivalinFairbankswastooccurduring thespringequinox,itmademoresenseto haveIcehengepointtotheoneharbinger
Displayedwithpermission?The American Surveyor?July?Copyright2008ChevesMedia?
Top left Chinese carvers position the two-ton blocks of ice to assemble the columns.
Top right A boom crane lifts the capstones into place.
Modern tools like metal scaffolding and a long reach forklift sped up the construction process, resulting in a finished product in just 11 days.
totheendofwinterforAlaska:thehigh noonsunonthevernalequinox.
TimSprout(ASPLSPresident-Elect) andIworkedtoproduceaCADdrawing basedonthebestavailabledimensions, tolayouttheoutsideringof30blocks thatmakeuptheSarsenCircle,the60 smallerBluestonesinsidethatring,and theninelargeststonesthatformthefive
trilithons in a horseshoe for the inner arc. (Atrilithon? a Greek term that means "havingthreestones"?isastructurebuilt fromtwoverticalstonesthatsupporta horizontalorlintelstoneacrossthetop.)
Layout at 20 Below
TheIceAlaskateamgetstwoiceharvests fromthenearbygravelpitpondper
season.Thefirstharvestyields18-inch blocks that are sold to local businesses forcommercialcarvingsinJanuary.The secondharvestyields4x6x3-footblocks thatareusedforbigcarvingsbythe competitiveexhibitorsinmid-February.
Daylightlastslessthanthreehours a few weeks after winter solstice, and temperaturescandropto30belowzero whentwilightwanes.Webegantolay outnailsinaskatingpondonadark, 20-below"day"inJanuary.
ThedimensionsofStonehengeare reallyrathermodestbytoday'smegalithic standards. The outer stones of the Sarsen Circleplinthsarehardlymuchmore than a modern hundred-foot diameter cul-de-sac.Theconcentricinnerringsand horseshoe-shapedarrangementsoccupy aspreadof25feetbetweenthehighest Trilithons, and an arced open ellipse of 19gravestone-shapedtaperedslabsface outwardinanopeningabout20feetwide.
Displayedwithpermission?The American Surveyor?July?Copyright2008ChevesMedia?
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