7 -- .I Natural Environment Research Council r- Institute of Geological Sciences ! - Mineral Reconnaissance Programme Report i A report prepared for the Department of hdustry It This report rdates to work carried out by the+Institute of Geobgical Sci8IIC8S On behalf of the Department of ~nduStQ’. The infOrm8tiOn contained herein must not b8 published without ref8renc8 to the I Director. Institute of Gedogical Sciences 0. 0St18 Programm8 Manager I Institute of G8ological Sciences _- 154 ClWk8nHlell Road .a_ London EClR 5DU -I a a No. 18 . A mineral reconnaissance t survey of the Doon-Glenkens 0 t area, south-west Scotland. P I 1.s L I I R a I I I ti INSTITUTE OF GEOLOGICAL SCIENCES Natural Environment Research Council Mineral Reconnaissance Programme Report No. 18 . A minera-l-rec~ e_s-urliWy of I the Doon-Glenkens area, south- west Scotland South Lowlands Unit J. Dawson, BSc J. D. Floyd, BSc P. R. Philip, BSc. Applied Geophysics Unit A. J. Burley, BSc, PhD Mrs J. M. Allsop, BSc J. R. P. Bennett, BSc G. R. Marsden, BSc Radioactive and Metalliferous Minerals Unit R. C. Leake, BSc, PhD M. J. Brown, BSc - -_ ._ C Crown copyright 1977 Edinburgh 1977 A report prepared for the Department of Industry c __ P--- Mineral Reconnaissance Programme Reports The Institute of Geotogical Sciences was formed by the incorporation of the Geological Survey of Great Britain and the Geological Museum with Overseas Geological Surveys 1 The concealed granite roof in south-west Cornwall arid is a constituent body of the Natural Environment 2 Geochemical and geophysical investigations around Research Council Garras Mine, near Truro, Cornwall . 3 Molybdenite mineralisation in Precambrian rocks near Lairg, Scotland 4 Investigation of copper mineralisation at Vidlin, Shetland 5 Preliminary mineral reconnaissance of Central Wales 6 Report on geophysical surveys at Struy, Inverness- shire 7 Investigation of tungsten andottrer mineralisation associated with the Skiddaw Granite near Carrock Mine, Cumbria 8 Investigation of stratiform sulphide mineralisation in parts of central Perthshire 9 Investigation of disseminated copper mineralisation near Kimelford, Argyllshire, Scotland 10 Geophysical surveys around Talnotry mine, Kirkcudbrightshire, Scotland 11 A study of the space form of the Cornubian granite batholith and its application to detailed gravity surveys in Cornwall 12 Mineral investigations in the Teign Valley, Devon. Part 1-Barytes 13 Investigation ofstratiform sulphide mineralisation at McPhun’ s Cairn, Argyllshire 14 Mineral investigations at Woodhall and Longlands in north Cumbria 15 Investigation of stratiform sulphide mineralisation at Meall Mor, South Knapdale, Argyllshire 16 Report on geophysical and geological surveys at Blackmount, Argyllshire 17 Lead, zinc and copper mineralisation in basal Carboniferous rocks at Westwater, south Scotland 18 A mineral reconnaissancesurvey of the Doon- -43enkwB area, swttwuest-So&and : Bibliographical reference DAWSON, J. and others. 1977. A mineral reconnaissance survey of the Doon-Glenkens area, south- west Scotiand. Mineral Reconnaissance Programme Rep. Inst. Geol. SC;. , No.1 8 Photocopied in England for the tnstitute of Geotogical Sciences by Museum Print and Design CONTENTS sunrmary 1. INTRCDUCTIOX 1.1 Aims and Objectives 1.2 Choice of ProjectArea 1.3 PhysicalDescription of ProjectArea 1.4 GeologicalDescription of the Area 2. GEXXEYSIC~lLSURVEYS 2.1 Introduction 2.2 GravitySurvey 2.3 AirborneSurveys 2,4 GroundFollow-up of AirborneSurveys 2.5 Conclusioos 3* FIELD SURVEXS 3J Introduction 3.2 Field Investigations 4. GEOCHEMICALSURVEYS 4J Introduction 4.2 Methods of SampleCollection and Analysis 4.3 Methods of Data Interpretation 5. RESULTSOF INTEGRATm SURVEYS 6. DISTRIBUTIONOF ECONOMICEUZ'ENTS 6.7 Introduction- 6.2 Distributionof Elements 7. CCNCLUSIONSAND REXOMMEHDATIONS ACKNOWLEDGE3ENTS BIBLIOGRAPHY APPE3DIXI Mineralisationin Pan Concentrate6 ILLUSTRATIOES Fig. 1.1 Outlinegeology of S W Scotland. Fig. 1.2 Projectarea and locationof formermines and trials. Fig. 1.3 Map of drainageand streamsampling points (backpocket). Fig. 1.4 Generalgeology of the area. Fig. 2.1 Aeromagneticmap (1972) of Doon - Fleet district. Fig. 2.2 CompleteBower Anomalymap of Doon - Fleet district. Fig. 2.3 Granite- sedimentmodel of Doon - Fleet district. Fig. 2.3a ResidualBouguer Anomaly map of the Carsphairnintrusion. Fig. 2,4 Model of Doon - Fleet district: Alternative1. Fig. 2.5 Model of Doon - Fleet district: Alternative2. Fig. 2.6 Sectionof model of the Doon - Fleet district. Fig. 2.7 Airborneelectro-magnetic map of areas flown 1973. Fig. 2.8 Aeromagneticmap of areas flown 1973. Fig. 3.1 Distributionmap of greywackeformations. Fig. 6.1 Distributionof copper. Fig. 6.2 Distributionof lead. Fig. 6.3 Distributionof zinc. Fig. 6.4 Distributionof molybdenum. Fig. 6.5 Distributionof iron'(as hematite). Fig. 6,6 Distributionof gold. An integratedreconnaissance survey was carriedout over 600 km* of Lower Palaeozoicsediments and Caledoniangranites in south-west Scotland. Airborneelectromagnetic (IPI), magnetic, and radiometricsurveys were made over three sectorsof the projectarea consideredon available geologicalevidence to offer environmentsfavourable to mineralisation. The B-4and magneticsurveys showed prominent amomalies associated with belts of black shalesand a numberof these are currentlyunder examination.No significantanomalies were indicatedby the radio- metric surveyand no importantradioactive mineralisation was found in groundsurvey follow-up. The gravitysurvey has improvedthe knowledge of the spatialrelationships of the major graniteplutons. Field and geochemicalsurveys led to the discoveryof many new mineralprospects. Gold, not previouslyreported in the projectarea, was shown by panningto have a wide distributionand severalinteresting copper,lead, zinc, molybdenumand tungstenoccurrences have been found. I 1 I 1.3 PhvsicalDescription of Projectllrea, 5e erea is coveredby one-inchto one-mileOrdnance Survey I Sheets 67 and 73 and one-inchto one-mileGeological Survey Sheets 4, I 8, 9, 14 and 15. 5e regionis dominatedby the ring of high ground formedby the I metamorphicaureole of the Loch Doon intrusion. 5e westernaureole includesthe Merrick (840 m), the highestpeak in the south of Scotland, t while the easternaureole forms the prominentridge of the Rhinns of I Kells. The Carsphairngranitic complex, in contrastwith the Loch Doon intrusion,rises above its aureoleto form the large roundedmassto the t north-eastof Carsphairnvillage. 5e main watercoursesof the area are the Doon, Cree, Ken and Dee; I the Doon flowingnorthward into the Firth of Clyde and the otherssouth to the Solway. The Doon end Dee drain the northernend southernhalves I respectivelyof the Loch Doon intrusion,while the Ken and Cree drain I most of the maminiq ground. 5e main watershedsand drainagepattern are showa in Fig. 1.3 (backpocket). I A large part of the area is coveredby young forest. 5i.s hindranceto free movementis more th,anoffset by the accessprovided t by the useful networkof new forestroads. I 1.4 GeologicalDescription of the Area The early conceptof the geologyof the SouthernUplands was of t a relativelythin, stronglyfolded sequenceof greywackes,siltstones and shaLesi A revivalof interestin the greywackesof this Lower I Palaeozoicsuccession, begun in the IPSO+, soon cast doubt on the earlierinterpretation. The modern view envisagesa thick succession, I dominatedby greywackes,laid&down rapidly in an Ordovician-Silurian I trenchenvironment. ,5is pile was subsequentlysubjected to strong t I NW-SE compressionalmovements which, eventually,produced fault-bounded blocks of nesr-verticslbeds. The stratigraphicalsequences within blocks csn be tracedfor considerabledistances along strike (NEXW) but s;redifficult to correlateacross strike (IrTw-SE). The culminationof the main period of erogenicmovement was aocompsniedin Lower Old Red Sandstonetimes by the emplacementof graniteplutons into the folded sedimentarypile. The principalintrusions of Loch Doon andCarsphairnare broadly similarin that they both have a centralacid phase encompassedby a varietyof more basic rocks which, in turn, sre in contactwith the countryrock. Geologicalopinion is dividedas to whether substantialportions of the basic faciesrocks have a magmaticorigin or sre derivedfrom the melting of sedimentary formations. !l?hegrsnitic intrusions were subsequentlyunroofed and now form importantphysicaL and geologicalfeatures of the Southern Uplands. The generalgeology of the area is shown in Fig. 1.4. !I!heSouthern Uplands have long been known to containboth noble- mets3 and base-metalmineralisation and in some areas intermittent . prospectingsnd mining has been csrriedon for centuries. Historibally the most productivedistrict was Leadhills- Wsnlockhead,which yielded lead-silverand zinc ores from near-verticalveins with WNW to NW and RNW to RYE trends. Significantamounts of base-metalores have been produced,mainly in the 19th century,from veins in the Newton Stewart districtand from Woodheadnesr Carsphairuvillage. I I T 2. GEOPHYSICALSUBWEXS t 2.1 Introduction I 2.1.1 Aims and Objectivesof Surveys 5e geophysicalreconnaissance methods used fall into three I categories: 1) 5e gravitysurvey t 2) 5e airbornesurveys, comprising electromagnetic (EN), magnetic 1 and radiometricmeasurements 3) Ground followup of snomaliesmeasured in airbornesurveys * 1 5e objectiveof the gravitysurvey was to definethe distribution of graniticrocks below the presenterosion surface. Significant t negativeresiduril Bouger