CompiledbyIainStobbs,JamesDaveyandCharlieOldman

SEG STUDENT CHAPTER TRIP REPORT: NORTHERN IRELAND

ThisreportdetailstheSEGstudentchaptertriptoNorthernIrelandfrom3rd–7thApril2017.

TABLE OF CONTENTS

Contents

Introduction ______________________________________________________________________________________________1

Background_______________________________________________________________________________________________2

Itinerary___________________________________________________________________________________________________3

Attendees _________________________________________________________________________________________________7

Acknowledgements ______________________________________________________________________________________8

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Introduction

InApril2017theUniversityofSouthamptonSEGStudentChapterorganizeda5‐dayfieldtriptoNorthern Ireland for 10 student participants. The trip was led by Dr Steve Hollis (UniversityCollegeDublin/iCRAG)andProfessorMarkCooper (Geological SurveyofNorthern Ireland) andfocused on the evolution of the Tyrone Igneous Complex during the Grampian orogeny,with aparticularfocusontheexistingmineralizationandfuturepotentialforexploration.

Theaimofthiscoursewastonotonlyfocuson‘deposit’scale,buttoalsoputthemineralizationinto a regional context. The trip was also designed to provide an opportunity for theundergraduate students todevelop fieldwork skills inanareaof activemineral explorationandexploitation.

Figure 1:A)MapshowingthelocationofNorthernIrelandwithintheislandofIreland.B)MapofNorthernIrelandhighlightingthestudyarea(redrectangle).

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BACKGROUND

TheTyroneIgneousComplexextendsoverapproximately350km2acrossthecountiesofTyroneand Londonderry, Northern Ireland. It consists of two main lithological Groups: The TyronePlutonicGroup(predominantlytectonizedandmetamorphosedlayered,isotropicandpegmatiticgabbros)andtheTyroneVolcanicGroup(comprisedofpillowlavas,volcaniclastictuffs,rhyolites,bandedcherts, silica ironexhalitesandargillaceoussediments). It iscloselyassociatedwith theTyroneCentralInlier(apsammiticandsemipeliticparagneiss).

TheTyroneIgneousComplexandTyroneCentralInlierformpartofthebasementoftheMidlandValleyTerraneofScotlandandIreland,whichbroadlycorrelateswiththeNotreDameSubzoneoftheDunnageZoneoftheAppalachiansinNewfoundland.ThiscorrelationlinkstoazoneofprolificVMSprospectivitywhichstretchesacrossCanada,toGreenlandandacrosspartsoftheRepublicofIreland and Northern Ireland, giving rise to increased interest in the mineral potential of theislandofIreland.

Figure 2:GeologicalbackgroundmapfromCooperandHollisunpublishedfieldguide.SummarisestheregionalsettingoftheTyroneIgneousComplexinrelationtootherrelevantgeologyacrossNorthernIreland,IrelandandScotland.

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Itinerary

Day 1 (3rd April)

The Chapter flew into Belfast airport at around midday and proceeded to meet Dr Hollis andProfessorCooperinthefieldintheafternoonatMountfieldQuarry,wherewesawbasalticTyroneArc volcanics, exposed immediately south of the Omagh Thrust, that had undergone extensiveepidotizationwithminorpyritemineralization.

Attheendoftheday’sfieldworktheChapterwasabletojoinundergraduatesfromtheUniversityofLeeds fora talkabout thehistoryof ‘IrishGold’and theCurraghinaltGoldMine,byDrGarthEarls. Dr Earls is a former Director of the Geological Survey of Northern Ireland and formerManagingDirectorofDalradianGoldLtd,theownersofCurraghinaltGoldMine.DrEarls’talkleadontothetourofDalradianGold’scorefacilityplannedforthefollowingday.

Day 2 (4th April)

In the morning the Chapter travelled to Dalradian Gold’s Curraghinalt gold mine core storagefacilityinOmagh,CountyTyronewherewemetProfessorCooper.Wewereabletoattendatourofthe core storage facilities, a presentation on the history of themine and also view show core.Examplesofseveraldifferentmineralizedveintypeswerestudied,withcorrespondingassaydataforkey intercepts alsoon show.Themorningafforded the students a first opportunity to see arangeofveincharacteristics,texturesandhostrocksfromthelargestknowngoldbearingsysteminNorthernIreland.

Figure3:A)StudentsreceivinganintroductorytalkfromDrSteveHollisuponarrivalinNorthernIreland.B)DrGarthEarlsprovidedaninsightfuleveninglectureaddressingthe‘historyofgoldinIreland’andthestorybehindthediscoveryoftheCurraghinaltgolddeposit.

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In the afternoon, Dr Hollis and Professor Cooper led the chapter to several sites across aprospectiveVMSdepositassociatedwith theupperTyroneVolcanicGroup.TheCashelRockAuprospect is hosted in mid‐Ordovician silicified rhyolites of the upper Tyrone Volcanic Group.Historic drilling across theprospect returned intercepts including3.63mat 30.51 g/tAu,withgold being associated with silicification and hydrothermal brecciation, forming a stockworkstructure.TheexactnatureofmineralizationatCashelRockremainsunclear,andstudentswereable toengage indiscussionas to itsorigin,basedon theirobservationsofhost rocks, textures,mineralizationandalterationminerals.

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Day 3 (5th April)

The groupbegan the day by visiting a series of localities throughout theTyroneOphiolite. Thetransectbeganwiththeinspectionofmagnetite‐bearingsilicaironexhalites(jasper),interpretedtohaveprecipitatedontheseafloorfromhydrothermalventsassociatedwithriftingoftheTyroneArc. Students then had the opportunity to observe some pillow lavas at Mweela More, wherecharacteristicoblatespheroidpillowscanbeseenwithdevitrifiedglassymargins,relictvesiclesand contraction joints. Stratigraphically below the pillow lavas, pegmatitic hornblende gabbrosanddoleritedykeswere studied atBlackRock.Remelting texturesbetweenpegmatitic gabbrosand dolerite dykes were studied, allowing for student discussion regarding mid‐ocean ridgeprocessesandgeochemistry.

In the afternoonDrHollis andProfessorCooper led theChapter to the final localityof the trip,Corvanaghan quarry. This quarry is within the Tyrone Central Inlier and freshly exposes

Figure4:A)StudentsinspectingDalradianResourceInc.showcorefromtheCurraghinaltgolddeposit.B)StudentsassessingmineralizationprocesseswithintheTyroneVolcanics.

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paragneisses which have undergone polyphase deformation. An early, bedding‐parallel S1foliationisfoldedbyisoclinalF2folds,withanaxial‐planarS2foliationwelldevelopedintheF2fold hinges. The host rocks are cut by a series of minor felsic intrusions including quartz‐plagioclaseleucosomesandlatermuscoviteandtourmaline‐bearingpegmatites.Inadditiontotheexcellentexposure,thislocalityallowedthestudentstovisitanoperationalaggregatequarryandobservethecrushingprocess.

Day 4 (6th April)

ThefinaldayconsistedoftravelbacktoBelfastviatheGiant’sCausewayWorldHeritagesite.TheGiant’sCausewayisworldrenownedforanoutcropofinterlockingcolumnarbasaltsandthevisitallowedthestudentstothinkaboutthetectonicevolutionofNorthernIreland,whichwasheavilyinfluencedbytheopeningoftheNorthAtlanticOceanduringthePaleocene.ThegroupreturnedtoSouthamptononthe7thApril.

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Figure5:A)Prof.MarkCoopergaveanintroductiontotheeconomicgeologyoftheCorvanaghanQuarry.B)Studentsgaininga3DperspectiveofgeologicalstructuresinCorvanaghanQuarry.

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Figure6:GroupphotoofallUniversityofSouthamptonSEGChapterattendeesattheGiant’sCauseway

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Attendees

1. CharlieOldman–3rdyearundergraduateGeologystudent2. JamieKelly–3rdyearundergraduateGeologystudent3. LewisBanks–4thyearundergraduateGeologystudent4. JamesShaw–4thyearundergraduateGeologystudent5. AshleyTuton–3rdyearundergraduateGeologystudent6. WillYoung–3rdyearundergraduateGeologystudent7. AlexSmith–3rdyearundergraduateGeologystudent8. CharlieKing–4thyearundergraduateGeologystudent9. IainStobbs–2ndyearPhDstudent–EconomicGeology10. JamesDavey–2ndyearPhDstudent–EconomicGeology

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Acknowledgements

TheparticipantsonthefieldtripareextremelygratefulforthefinancialsupportprovidedbytheSocietyofEconomicGeologistsandfromouracademicadvisor,ProfessorSteveRoberts.

Wewouldalso like toplaceon recordaparticularnoteof thanks toDrSteveHollis (UniversityCollege Dublin/iCRAG) and ProfessorMark Cooper (Geological Survey of Northern Ireland) forsharing their expertise in the field. Additional thanks are due to Orla McKenna (DalradianResources Inc.) for a superb tour of the Curraghinalt core facility and to Dr Garth Earls for aninsightful presentation on the history of gold in Northern Ireland and of the discovery of theCurraghinaltdeposit.DrKoenTorremansandAlexRussellprovidedexcellentadditionalguidancewhilstinthefield.

Finally,adebtofgratitudeisowedtothosewhohelpedtoorganizethelogisticsforthetrip.TheseincludeAislingHubert,CharlieOldman,WillKnapp,JamieKellyandJakeLaunder.