Bergvesenet Postboks 3021, 7002 Trondheim Rapportarkivet Bergvesenetrapport nr InternJournalnr Interntarklvnr Rapportlokalisering Gradering BV307 141/59 VB Trondheim Kommerfra..arkiv Eksternrapponnr Oversendtfra Fortroligpga Fortroligfra dato: østlandske Tittel Aeromagnetiskemålinger i Arendalsfeltet Interpretationreport Forfatter Dato Bedrift des 1958 Hunting GeophysicsLTD Kommune Fylke BergdistrIkt 1: 50 000 kartblad 1: 250 000 kartblad Aust- Agder Østlandske Fagområde Dokumenttype Forekomster Geofysikk Råstofftype Emneord Malm/metall Sammendrag
AN AEROMAGNETIC SURVEY IN THE ARENDAL REGION NORWAY FOR DET KONGELIGE DEPARTEMENT FOR INDUSTRI OG HANDVERK INTERPRETATION REPORT OCTOBER 1958 HUNTING GEOPHYSICSLTD. WIDER(SE FLYVESELSKAPAn 4. ALWIARLE STREET AUGUSTAGT 19 LONDON W.1. OSLO.
AN AEROMAGNETIC SURVEY IN THE ARENDAL REGION NORWAY FOR DET KONGELIGE DEPARTEMENT FOR INDUSTRI OG HANDVERK INTERPRETATION REPORT 4 OCTOBER 1958 HUNTINGGEOPHYS1CS LTD. WIDERØEFLYVESELSKAP A/t 4. AUSEMARLESTREET AUGUSTAGT19 LONDONW.I.
arkla31100 o /9111 son otea NO/MOWDEUZI *I mans surro asiorrama SaCIMIZENT QM7 SIGItnt *II PaXadsansvoxv oc Ataans eq; jo osodzna *g ummuojui Twasmoo -c u0t;tucutwo (A;) PJOOGE (!;/) Z V T wauina:;etri (TT) Potnatt (T) ista?guro;auktayt euaoqat7 oqy mit3 (TT) C Z 4newnflan Tinv pow}ow (T) imemo RaTuoT4Teoclmm5 &T Tn otnr og 4.1my 2uTpveR (q) qmoy ter/ (18) sq.90/ (A) SMOIST~ 241.17i *Ii/ :4402 [T4Ty ottara *z eqsloy (TTT) 4-39~ IT If uagflva Ix11311 *9 suratclakt reuonnpwx (rn) 4r aegivoit (TT) eouvuelaripm pre A.TITqweoTAaGg utuarp7 (T) 'tt poseinnoom sumosa TeuoT;w8Txex pinv ScrTtra 4 01414-031leu 0T;v9TA 341 sotinom owqa pue JOA00 OTirtex204,0q1 etideg e setøg
Page No wiarriam~ao. nigin IJX at.:ing anddireotion 4 PlyingHeight 4 Reflying 4 Supplementary Plying 4 7. AirbornoProote 4 WarmingUp of Instruments 4 Annotrtion ofrrerda 5 (511)DailyFlightReporta 5 IV. MAGNETICCONZRULERWEDURES 5 Control ofcloservptions 5 InstrumentSt 5 External Oheokon Magnetio Disturbanoss 5 V. PINZJA2MMOTIONOFDZO. 6 Flottingof PlightPath 6 TransferofPlotted PlightPath 6 3. RelatingProfilesto theflottedplightppth 6 Datum Lining anl Interoepting 6 Coptouring 6 Work Sheets 6 VI. COMPD.:21ONOP MLFS 6 1. Base Mekpa 6 2. Preaentation 7 VEc.En.LABEDIE 7 2. IdaisonsithClientduringSurvey 7 2. Matertal Suppliedto Client 11.4233 IndemtoLineenovni 7 Looation Siap (shawingflightlineandahoetle,yout) 7 SpeoimenGulfMKIIIMagnetameter Reoord 4. SpeoimenS.P.N.1 RadioAltimeterRooard
5. Identifloation of PlightPats.2 6, EggipmentFhotographs A. Looldieed 12 Airoraft 3. GulfMKIIIMagnetomater DateotorBead 0. GulfBKI/IMagnstomet..er Oonsole LeedsNorthropRecorder forthegulfmagnetometer The4.P.L1RadioAliUmetershowingtraneuitterfreeeiver vnitpantennaendidlotindioator P. TheVinten35mmoemer andintersralomøter
I. INIRODUCZION 1. Generalinformation (i) Theaerouagnetio surveydesoriluwibelowwws oarriedout in thearendalareaofnorwayonbehålfofdetkongel1ge Departement forindustriio Og Handverk.Itwasoarr.lni outjointlyby WideroeFlyveselskap A/SandBUntingGeophyalos (ii) Thesurveyoperational tlmeextendedbetweenthe 28thSeptember, 1958,andthe9thOotober,1938. Theexpedition personnelconsintedofs- ti se of thes. 2 Ellots(WAdercePlyveselskap A/S) 2 Navigators (Wideroe114veselskap A/S andbuntinggeophysios Ltd..) 1 LioensedAiroraftEtgineer(Wideroe Flyveselskap A/S) 1 Eleotronio Itgineer(Runtitg Geophysios Itd.) (1) To oomparethemagnotiopatternobtainedoverthearea withthekaowngeology. (1i) To examinemagnetioanomaliecin relationto theknuwn måneraldeposits. To deriveadditional infornation aboutgeologioal trends andto investigate theprobabllity of existenceof unknownmineral deposits. 3. AreaSuoveved (1) Theareawaaoentredaçroxixntte1.y on thetosnof Årendal, latitude380271t1longitude8 4,51%beingreotangular in ahapeanl havingapproximete dimensions 30 kmex 16 kma. (ii) Theaotualoontraotlinemdles/kmeflownwore698and1,123 respective1y. 3N/R018ANDDemmies zmazzedon TBESTIMEY A. TheAirhorne tometer Method In theaeromagnetio methodemployedon thissavey,variations in thetotalmagnetiofieldeeremeasured.as theinstrument does notmeasuretheabsolutevalueof thefield,theobservations are relatedto an arbitrary daturn, Instrument(Elates 6B,60,6D) Theinstallatjon consiatedofgulfresearohanddevelopment Companynagnetcaeter MKIII. Thedeteoting pavtof theinstrument wesinstalledin thebirdwhiohwastowedbehinatheairetatt. /Thieinetrument
/Theoamera -2- Thisinstrumert was.of-flumeate type. Themeasuring flumgate wasmaintained thedireotionof thetotalmagnetiofieldthrough theactionof theservomotorsoperatedhy twoorienting fluxgates. Theeffeotof theambientmagnetiefieldon themeasuring flaxgateiscempensated andthevnitageohangesaorosethe recorulnz potentiometer dueto theohangingconpenaating ourrents arerenordedoontinuously termaof magnetiounitaon the recorderohartof & LeedsandNorthrupMeoarder. (iii)recorå(flate3) Thmspeedof therecordwas6" perwinuteandthefullsoale deflection wassettobe 1,200gamoss. Thevalumof thestep ohas:ge (anautomatio resetprocedureoperating whenthemagnetio fieldvariations axoeedtherangeof thefullscale)was1,0 gemmas. (1v) Calibration Theinstrument waaealibrated by GulfResearohandDevelopment Corperation usinga ReltholtzColl. (v) Taste Lan Test /mg (ordelayof theresponseoonsidered in relationto the grotlyositionof theairoraft)is dueto thedelayin theeleotronic oirouitryof theequipmentandthedifferenoe in thepositionofthe 35mmpositioning eamer andthedeteotorheed. A teetwasflownandthelagwasfoundto be 0,75memondm whichis equivalent to 0.075inoheson therecordi at a speedof 6 inoheayerminute. Theoffeetof therecordingyenfromtheoamerafiduoial penrangedfrom0.225to 0.25inehesandwasaddedto.khe eforementioned lag. ReadinnTest Theeffeotof theairoraft'a magnetiofieldon thetwoorded variations ef thmwagneticfield,dependson theheadingof the airoraft.compensation canbe madefora partof thiseffeot. Aheadingtestis carriedout in orderto oheoktheoompensation of theaircraftandto aseesstheunocapensatedresidual effeot. Theresultsof theheadingtestflownonthissurvey, at en altitudeof 500feetåbevegroundlevel,showsthe maiimumohangepeakto peaktobe 2 ganmme. B. AncillaryBquiPment 1, ar!inaitio Camara (i) pethodanlinstsmeent (Plate67) A.Vintenpositioning oamerawasmountedintim airoratt withitsopticalaxisvertioalforlevelflightof theairoraft. Exposurest re mde automatioally at1 seoondinterva1, Thespeedof theahutterwas1/250of a seoond,andthe ayerturewasveriedmarmarly acoording to thelightittensity.
The oameraexposures-ierelatedso the magnetiereoordby a systemof fiducialmarke. The eiposu.:e colnterwas also photographedandthe photographnumberappearsin the oornerof eaohphoto-frams. Pilm (Flate5) Too fibmusedwas KedakPlus X. It was prooessedbythe SurveyTeamandby GeorgeHumphriesandGompapyof Londmm. Tests The funotioningof the camfl wat testedbytakimg& series of exposuresin flightand developingthe filmpriorto the ocemenoementof the survey. S5ad1ar testswere alsocarried out duringthe survey. 2. RedioAltimeter(PlatesL1and 6E) Apartfromthe berometriéaltbreterwhichis a standard inetrumentoarriedin the al=aft, a radioalilmsterof the typewas alsooarriedm ThefUllscalerangewas 0-e00feetand the speedo: thereoord,on whichvarlationsof altitudmof the eiroraftabovethe groundwererecorded continuously, was 6 inchesper mdfinte. III.FLTIM GPERATIONS Airoraft The alroraftwas a Lockheed12,registration lettersln-bps, belopgingto WiderceFlyveselskap., r. The afrowaftims equimed withnormalradioequipment. The aircreftwas basedpt NjevikAdirpcm.t, Kriatiansand. The airfleldwas 60 mdlometresfromthe surveyaream' The orowwereaccommodatedat the AstoriaHotel,Kristiansand, whioh is approximately 14 kdlometresfromkjerlicidrimwt. Ma Ph ' 1)cverendPhot6Mosatog 3/50,000scalemapswereusedfor navigation andf11ghtplanning. A 100,000soalemap was alaousedfor flight planning. Thismap was enlargedto 1/25,000but thisenlargement was notusedoperationally. (11) PhotographioGover (a) Yhotographicprintswere suppliedbywideroe Plyveselakapat the ocamencementcf the survey. Theseprints wereat threedifferentscalesrangiwgfrom1/15,000to 3/20,000 andonbypartialiycoveredthe area. StickCownwoosicswere compiled,but werenot usedoperationally. Ab)
/(u) (t) Aritltionarphotographio oover:wastoundiatbe aurveyirooeededandthe000pletesetot oentaatprintswere usedsa thefinalreduotion. (iii)photomosaics Semloontrolled mosaioat a aoaleof 1/25.000(approx.) wereoonatruotod andmcuntedoncpagraforfinalpresentation Sevioational Method Thenavigation of theaurveyareawasp000mpliabedby mapreadingusingthe170,000mapsmeutionedabove. 5, andnavlationalproblems tered (1) AiroraftServioeabiliaad tenance SO delayswereexperienoed dueto unservicmabittkr of tha airoratt. (ii) 1148.12.5E Sevendaye.were låstbeoauseof inolesent weatheroaused by low stratus. (111)N ationalprobleme Owing'tomapswhiohwerea littieinaoouratetemakingwees foundtobe affloultin oertainareaswheredetallwaasparae. 6. t Pattern(Elates1 and2) t Line8 ao aml ThePlannedflightlineepaoingwasi'briandthetrue direotion510 430.. Thepatternmibievedis as ahownon thetinalamp. njugal Theganned nominalflyingheightwaa150metres(500femit) abovegroundlevel. (111)liaTa (seeplate1) A.eertainamountof ref1yingwaaoarriedoutdusto navigational erroreandinatrurent defeots. (iv) a Theflightlineswereectended.from thema$ ooastlina to amallerislandsin areasof interest. 7. rnaprooedure (1) of Instrurents.411instnmentswereswitohedon andkoskrur~ tor at 1eastbalfaa hourbeforereoording beganto ensuretheir proper.and ateady-funotioning.
(ii) Annotation cf Records Duringthesurveytherecordewereannotatedforreduction andiecttingpurposes. Thefollowingannotations weremadesa Startawlendof linegivingnuffiber anddireotion b Stepnumbers Cantxafiduoialnumbers Iwyttement driftcorreotions/indioationt Nevigational fixes. Timecheoka Otherrelativeinformation (111)D t Re rts Thesereportagive a detailedesoription of taesortietrma an operational pointof vdewandshowthefollowinginformationva Timesof startandendof sortie b Instruments imedandrelevantdetails Onmvmembersandfunctions 55mmphotograph nunbers Timesof startandfindahof lines Direotionof linesflown / Changeaof magasdnea, charteretc. Weather?1 Navigatorla diagramshowingthescrtielsflying IV. MAGNEXICONTECLPROCEDURES 1. Controlof Observation Theoontrolof observations was achlevedbyterminating the endsof eachlineovercommontiepoints,oonneo:ling the tiepointsby an independent tielineand flyiraganother tielineaoroasthenorthernendsof thelines. Thissystemof controlmadeit possiblet- 2. Inatrument Drift To establisha c.ommon referencedatumfor thewholesurvey. To determineandadjustsmallerrorsoaused byinstrumentaldrift,diurnalmegnetie variations, ndrlorlooalmegnetiodisturbanoes. Instrument driftwascheckedat intervalsaf approximately every15 minutes. Standardisation adjustment wasoarried outwhennecessary. 3. ExternalCheokon neticdisturbanoes In orderto detectar4rmajormagnetiodisturbanoes which couldhaveoccurred,a verticalfornemagnetometer (Schmidt typeandasisinia manitacture) wes setup atkjevikairpert, Xvistiarsands.
-6- V. 1TNALREDIVTIONOF fltlfl tlott offl htfath (i).thiswas adhievedby identifying pointsfrmms4eotedfremase of 35mmfilmon photographe Thepoint seleotedforjaentifioation wereasongtheflightlines at an averagedistanoeof 750metres,thiadistanoebeinggreater in areaswheredetailwaasperse. TransferofPlottednightPath at scalesof 1/15,00etQ 1/20,000(approx.: Thepointsplottedweretransferred to astrafoil overlays to photomosaiosmountedon Pagraat a scaleof 1/25,000(approx.) Relati Profilesto theflottedfliahtpath Allplottedandest±mated pointeweremarkedon therecord, usingthephoto-frame numbersandthecorresponding fldmoial marks,afterallowance hadbeenmadeforlag. DatumL andinterce (1) Reoordedprofileswerereferredto a 00=11 datmt basedon tiepoints. (il) Intercepts werereadfromprofilesat minim andmasdam. Alsoat intorvalsof 20gabmasin areasof lowmagnetiogradiemt andat 100gammasin areasof highmagneticgradient. (1i1)Theinteroepts weretransferred to theoverleysmaking dueallowanoe forhorizontal scalebhanges. 5. Oontourina Intercepts transferred to theoverlayswereoontouredat intervalsof 20 gammesin areasof lowmagnetiogradie tandat 100gaMmasin areasof highmagnetiogradient. '6, WorkSheets Copiesof themagnetioontourworkeheetson Aocurens transparent Materialandworkingdepyphotomosaicamountedon linenweregivento theollenttsrepresentativee. VI, 00MpTh.ZION OF CONTOVRMAES 1. BaseMaps TheBeeeMapsare semicontrolled.photo mosalcsat a soale or1/25,000(approx.)mountedonpegra, NOTE: Tuplioation andomiesionof topographio detailexistson thephotomosaicmused as a bezieforthepresentation of the geophysical data. Theyhaveaffeoted theancmalypatternpresented. shouldbetakenintoaocountwhena detailedstudyof anamalypositionand ahape53made,
2. Preeentation Ihefinalmapsarepresentedon transparent astrafoil andoverlaythepegraphotomossios. Thetopographioal detailis takenfromthebasemepsand presented inblaok. Plightlinesareshowninblaok anftplotted.35eza pcdnta areshownst intervalslongthelines, (1v) ThemagnetioontoursareshOwnin red. MISCSMASS0U3 1. LiaisonwithClientd Stne, Messrs.Aalstad(Geophysioist) anddorgan(techrioian) weretheolient'srepresentativis ataristiansand anlhunting GeopLysios laboratories, London,mhils theflyinganddata reduotionwasin progress. Wite S to theclient Thefollowing maps,mosaos,reportsandreoordawars suppliedto theelient:- at. 000 (wpw«..).oneoopyof thefollowings- a3 KagnetioContourWorkSheetsonAciourene. {l b Pina MagnatioContourmegeontransperent astrafoil. (o) Interpretationmap, Mosaiosat "2 006(npprox.) Oneoopyof eeohof thefollowingt {a; b Worldngoopymountedonlinen PinalmossiomountedonPagra Renorts Twooopiesof theoperational Report Tw000piesof theintarpretationrepert Reoorde AirborneGeophysioal keoordsoonsisting of:- b RadioAltimeterReoord a 35unfile 1ia d DailyPlightReports AizborneNagnetaister Reoord'
INIZCTOLneaFLOWN ILATS1 Anauraeno SURVEC- ARSICAL'AIMA(scetta) E.G.L.SURVECN3sG170 No pf 'Flight Line -True' direetion Date Flant of Flight Linea(in degrees) Sortie Rol, (where amlicsable) Remarks 1290 4/10/58 1 RF 309 8/10/38 2 2 1290 4/14/59 3 129 4/10,59 4 1290 4/10/58 5 129 4/10/55 6 129 7/10/58 1 7 129 7/10/56 1 7 TOP 1290 8/10/58 2 8 1290 744/58 2. 9 129 744/58 1 10 129 740/58 1 11 129 744/58 1 12 123 140/50 1 13 129 1/10/58 1 14. 129 750/55 1 15 1290 7/14/58 1,6 309 444/58 17 309 4114/58 1e 3:9 4/10/59 19 309 440/59 20 3090 4/10/58 21 309 7/14/58 1 22\ 309 744/59 3. 23 3090 7/14/55 3. 23.BP 309 7/14/58 24. 309 740/59,es 309 7/14/58 1 2 RF 309 7/14/58 1 Jleflown dueto navigetsiona1error(partused itreduotion) neflowndueto navigationalerrzn.spert use& in reduot RedlxmndUeto nnvigationalerror(pertused. inreduotion) Reflowndueto inatrumen* error '
No af Tr.ue Date Sortie Plight direotion Plown No, Idne of Plight (where ' Lines (in applioable) degrees) 26 27 26 3090 3090 3090 7/10/58 7/10/58 7/10/58 1 i. 1 28 RP '309" 740/.59 i 29 3090 7/10/58 2 30 309 7/10/58 2 31 309 740/58 2 Reflown due to narigats. donvill=0.4part ueed in r 32 309 7/10758 2 Reflowndue to lonel error in reduotion) navigat- (pert una.32 EP 309.7/4/58 33 3090 7,414/58 2 34, 3090 744/58 2 Reflown due to naitgat-p ionel.erroy igert used in rednotionj 34.3P 309c, -740138 35 309 8/10/58 38 H 309 840/58 1 i 37 sor 8/10/93 1 38 3C9 8/14/58 1 39 3090 4/10/58 1 40 129 844/58 1.41 129 8/10/58 1 Reflown due to nerlipa.- ional error 41113 129 8/14/58 1 42 129 8/10/58 1 43 3090 8/1Q/58 2 44 129 4/10/58 2 45 129 740/58 2 48.129 7/10/58 2 47 129 744/58 2 48 129 740158 2 49. 129 7/10/58.2 30.,.., 1290 7/10/58 2 51 129 7/14/51 2 52 129 744/58. 2 /33 309 4,10/58 2 511. 309 4/34/59 2 55 309 4/10/58 2.56 309. 840/58 2
No.of Ilight Line True dirootion Dato Flown of Lines ln degrees) Sortie NO. (where applioable) nrks 57 309 W10/58 k_ n 58 129 4/1Q/58 2 59 1290 8/10,/ti9 2 60 129 8/1(1/58 2 61 129 8~58 2 62 129 4/1q/58 2 NU,of TieLine 3. 2200 8/1,0/98 2
LOCATIONMAP,SHOWINGFLIGHTLINESAND SHEET LAYOUT. no t ' 1 50' 1 4 01 ansna fl se6c, eoo' se 10' oe I. SHEET 2 ----= t1,40' 8. SHEET I le ead mo m. 11* th. 21114). VUIT 0. 0 Le weinnas n ut Il'a#1. Chumanu..
Plate no 3, SPECIMENGULFMKmMAGNETOMETER,RECORD 1 For text- of KIKKIONI a 07.1.):114 WIOIIIAJOD
SPECIMENAPNI Plate no 4. RADIO ALTIMETER RECORD
PLATE No. 5 IDENTIFICATION OF FLIGHT PATH 441 I 1; t' ' ' I. C't AERIAI I'I IOTOGRAPH I : 10.000 TOPOGRAPHICAI I : 25,000 MAI' 4 35 MM FILM
PLATE N 64 P tu rnå: Lockheed
Gulf PAkm mognstomster detictor Mod PLATEN 6B
PLATE N 6C 1111. t. Gulf fakz Megnefomate consolu
PLATE N 6D 00 200 X0 100 500 : Leeds Northrup reeorder for the Gulf mognetomefer
PLATE N 6 E The APN I. Radio Altimeter showing tronsmi Itsr/ receiver unit, ontemo ond pllots IndkOtor
PLATE N 6F I. ne vinten 35mm eamera ond intervolometer