No. 18 - January 2011

Sediment-hosted copper in Greenland

With the growing world populationand with the technological advances,copper will continue to be a veryimportant commodity. The mineralpotential of Greenland is underex-plored. However, this magazine illus-trates that Greenland could hold agood potential for undiscovered Cudeposits. Especially the large sedimen-tary successions in Greenland arefavourable for sediment-hosted cop-per occurrences. Occurrences relatedto the Reduced-facies (Kupferschiefer)Cu, Redbed Cu, Revett Cu and VolcanicRedbed Cu types have all been discov-ered in Greenland. However, in mostcases the known occurrences haveonly seen very limited investigation asonly few exploration campaigns havebeen focused on copper.

Introduction

Sedimentary basin environments youngerthan 1600 million years (Ma) constitute c.40% of Greenland’s 410 000 km2 ice-freeland. Of this, the Phanerozoic basins (<400Ma) accounts for c. 20% (31 570 km2), theLower Palaeozoic and the Neoproterozoicbasins for c. 50% (85 280 km2) and theMesoproterozoic basins for c. 30% (47 970km2). These basins are well-known for sev-eral mineralisation types of which sediment-hosted copper, in the form of especiallyReduced-facies and Redbed copper types,are some of the more encountered types.However, only limited exploration has beencarried out on copper deposits hosted inthe sedimentary successions.A ‘Workshop on the Potential for Undis -

covered Sedimentary Hosted Copper De -posits in Greenland’ was held in 2009. Thepurpose of the workshop was to assist themineral sector in their planning of new ex -ploration targets and provide the sectorwith the scientific background and neces-sary data to make qualified decisions. Theworkshop was arranged by the GeologicalSurvey of Denmark and Greenland (GEUS)and the Bureau of Minerals and Petroleum(BMP). The workshop was also part of thecooperative international effort ‘Global

Mineral Resource Assessment Project’(GMRAP) led by the U.S. GeologicalSurvey. This magazine highlights some of

the results from this workshop, includingcharacteristics of the main sedimentaryprovinces in Greenland, their known Cudeposits and the resulting potential forundiscovered Cu deposits within theseprovinces.

How to evaluate undiscov-ered Cu deposits?

During the workshop, an eval-uation of the potential forundiscovered sedimentaryhosted Cu deposits inGreenland was carried outaccording to the standard-ised process utilised in theGMRAP. In this process, anassessment panel of experts dis-cusses all available knowledge and dataaccording to the mineralisation type about aspecific area (tract) and assesses the possi-bility of finding deposits within this tract.The expert panel consists of geologists, geo-physicists, ore geologists, etc. with specialistknowledge about the geology, mineralisa-tion or mineral deposit model considered;both from academia and industry. Eachtract is defined down to 1 km depth belowsurface. The members of the assessmentteam make their individual, anonymous esti-mates (bids) of the number of deposits of aspecific size and grade they believe can befound and mined in a specific tract, underthe best of circumstances. This is done ondifferent confidence levels. A panel discus-sion of the bids leads to a consensus bid,which is used as input to a statistical simula-tion. The result is an estimate (prediction) ofthe size of un discovered tonnage of ore andnumber of tonnes of the commodity inquestion the tract contains. The statisticalsimulation includes global inventories/curvesof tonnage and grades about knowndeposits/ mines of the mineral depositmodel in question. The deposit size andgrades that the members of the assessment

panel give their bids on are defined by themedian of the grade-tonnage curves.

Copper deposit types covered

Sediment-hosted Cu deposits account for c.23% of the world’s Cu production andknown reserves. They are also importantsources of Ag and Co, and some depositsalso produce other metals such as Pb, Zn,U, Au and PGE.

Sediment-hosted copper deposits are strata-bound epigenetic and diagentic depositsformed independently through igneousprocesses. They occur most commonly insedimentary basins that contain marine orlarge-scale, lacustrine rocks with evaporitesthat immediately overlie continental redbedsand in isolate nonred units within the red -bed successions themselves. In general, theyare formed within 30° of the palaeo equatorin arid environments and in sedimentarysuccessions associated with intra cratonic,long-lived rift or passive margin settings.Genetically, they form as a result of fluidmixing in permeable sedimentary and (morerarely) volcanic rocks. Two fluids are

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1 Sediment-hosted copper in Greenland - Assessment of potential and undiscovered Cu deposits

Distribution of tracts with sedimentary successions that areregarded as having potential for sediment-hosted copperdeposits in Greenland.

Mesoproterozoic Independence Fjord Basin Independence Fjord Group

Neoproterozoic Eleonore Bay BasinEleonore Bay Supergroup

Neoproterozoic Hekla Sund Basin Hagen Fjord Group

Phanerozoic Jameson Land BasinPermian and Triassic Formations

Proterozoic Thule Basin Thule Supergroup

0 200

Km

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Mineral deposit subtype

Reduced-facies Cu

Redbed Cu

Revett Cu

Volcanic Redbed Cu

Synonyms

Copper-shale,stratiform copper hosted by low-energy sediments, marine paralic,Kupferschiefertype, CentralArfrican type

Redbed-hostedCu, sandstone-hosted Cu, conti-nental redbed

None

Basaltic Cu,Andean mantoCu.

General description

Stratabound,disseminatedcopper sulphidedeposits inreduced-faciessedimentaryrocks overlying or interbeddedwith redbedsequences orsubaerial basaltflows.

Stratabound, disseminated copper and copper sulphidesoccurring inreduced zones of redbedsequences.

Stratabound, dis-seminated copperand lead-zinc sul-phides occurringin broad redoxboundaries.

Disseminated,native copper and copper sul-fide veins andinfilling amyg-dules, fracturesand flowtop brec-cias in the upperparts of thicksequences of subaerial basalt,and copper sul-fides in overlyingsedimentary beds.

Minerali sation

Copper mobilisedby oxidisedbrines; the re - ducing suphide-bearing fluids are derived fromreduction of sulphate in marine or lacus-trine, organic-rich, fine-grained sediments. Sabk-has, eva -porates, or other sources of brines areimportant.

Copper mobi lisedby oxidisedbrines; the reduc-ers are formed bythe presence ofplant debris. Insome cases localevaporate bedsare present.

Copper mobi lisedby oxidisedbrines; the reducer is abroadly distrib-uted and diffusefluid, typically ahydrocarbon liquid or gas, or sulphide-richsour gas.

Copper mobi lisedfrom volcanicrocks during diagenesis orearly-stage metamorphism;precipitation inpermeable loca-tions underfavourable chemical, pressure, andtemperature conditions.

Depositionalenvironment

Formed in conti-nental clastic sedimentarybasins succeededby epicontinentalshallowmarine or lacus-trine basin.Within 30° of thepalaeoequator.

Found within host rocksdeposited by alluvial systemsentering closed-basin playas orcoast-al enviro-ments, shallowseas and evapo-rate basins.Within 30° of the palaeo -equator.

Deposited as fan deltas enter-ing closed-basinplayas or coastalenviroments, shallow seas andevaporate basins.Within 30° of the palaeoequa-tor.

Copper-rich continental toshallow marinebasalt interlayeredwith redbeds inarid to semi-aridenvironmentsformed nearpalaeoequator.

Ore control

Pyritic shales,algal mats or reef colonies areimportant asreducing environ-ments. Late oro-genic develop-ment of fracture-permeability andhydrologic settingto drive theprocess of fluidmixing is impor-tant.

Permeable sandstone bedsare a controllingfactor. Pyrite canbe a significantlocal reducer ifpresent. Redoxfronts (roll fronts)in ore-formingfluids and disequi-librium conditionsare importantchemical controls.

Permeable bedsare important.Redox front (rollfront) controlscopper deposi-tion. Nearbymarine basinswith deposits ofhy-drocarbon aresources for theformation ofreducing fluids.

Flow-top breccias,amygdules, frac-tures in basalt; or-ganic shale, lime-stone in overlyingse-quence. Asso-ciated reduced,carbonaceoussedimentary rocksmay play a role.Synsedimentaryfaulting may beimportant.

Host rock types

Shale, siltstone,mudstone, clay(reduced faciesmarine or lacus-trine rocks).Organic carbonand disseminatedpyrite commonconstitu ents.

Redbed se quencecontaining white-or grey-bleachedzones in sand-stone and/orblack, grey orgreen, reducedbeds of shale andsiltstone.

Sandstone,quartzite, arkoseand conglomer-ate.

Shallow marinebasalt flows, brec-cias and tuffs,redbed sand-stone,tuffaceous sand-stone, conglomerate.

Ore tonnageand grade

Median ore ton-nage of 33 Mtand a mediancopper grade of 2.3 %.

Median ore ton-nage of 2 Mt anda median coppergrade of 1.6 %.

Median ore ton-nage of 14 Mtand a mediancopper grade of 0.8 %.

Not applicable.(USGS grade- ton-nage curves havenot been estab-lished).Kirkham(1996):28 deposits withan ore tonnagefrom 0.85 Mt to220 Mt and acopper gradefrom 0.8% to 12.8% Cu.

Global examples

Kupfershiefer(Poland),Zambia deposits(AfricanCopperbelt,Zambia).

Corocoro (Bolivia),Nacimiento andStauber (NewMexico, US).

Spar Lake andMontanore-RockCreek (Montana,US),Cashin Mine(Colorado, US),Dzhekazgan(Kazakhstan)

Keweenaw andCalumet(Michigan, US),Kennicott andDenali (Alaska,US),Boleo (Mexico),Buena Esperanza(Chile),Redstone andSustut (Canada).

Fact Box General characteristics of sediment-hosted copper deposits

Characteristics of the three first subtypes of sediment-hosted copper deposits are extracted from Cox et al. 2007. The cited medians of the ore tonnage and the coppergrade are extracted from the established grade-tonnage curves. The characteristics of the genetically related Volcanic Redbed Cu deposit type are mainly extracted from Cox1984 and Kirkham 1996.

involved, an oxidizing brine that carry cop-per and a reduced fluid, commonly formedin the presence of anaerobic, sulphate-reducing bacteria. Mineralisation in the sedi-mentary Cu systems occurs from early dige-nesis to basin inversion and metamorphism.Overall, to form a sediment-hosted copperdeposit four conditions are required:

1. An oxidizing source rock that is hematite-stable and must contain ferromagnesianmineral or mafic rock fragments, fromwhich the copper can be leached.

2. A source of a basinalbrine that mobilisesthe copper.

3. A source of reduced fluid to precipitatethe copper and (in many cases) a supplyof sulphur.

4. A structural and stratigraphic settingfavourable for fluid mixing between theCu-bearing brine and the reducing fluidand subsequent sulphide deposition.

According to Cox et al. (2007) sediment-hosted copper can be divided into threedescriptive mineral deposit models: Reduced-facies Cu, Redbed Cu and Revett Cu. Thethree types differ in the strength and effi-ciency of the reducer at the site of deposi-tion. Furthermore, the genetically relatedfourth type, Volcanic Redbed Cu, is includedin the assessment.Occurrences of sediment-hosted Cu are

relatively frequent within sedimentary suc-

cessions regarded as fertile for this type ofmineralisation. However, the vast majorityof sediment-hosted Cu mineralising systemsproduces small, mostly subeconomic occur-rences. Nevertheless, large deposits arefound within all of the above Cu mineraldeposit types. Especially the Reduced-faciesCu type can form very large mineralising

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Spectacular outcrops of the Neoproterozoic Eleonore Bay Supergroup which hosts several known Cu occurrences of the Reduced Facies Cu type alongthe coastal cliffs (height up to 1000 m) of Geologfjord, North-East Greenland. Photo: Martin Sønderholm.

S E D I M E N T - H O S T E D C O P P E R I N G R E E N L A N D

Malachite-stained outcrop of quartzitic sand-stone from the Brogetdal copper occurrence inthe uppermost Lyell Land Group of theNeoproterozoic Eleonore Bay Supergroup inStrindberg Land, North-East Greenland. Photo:Henrik Stendal.

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50 km

Level 3 - Cu in quartzite, 0.5-2 m thick, average <0.1% Cu

Level 5 - Cu in quartzite, 0.2-1 m thick, average <0.1% Cu

Level 0 - Cu in quartzite, 0.2-1.5 m thick,average <0.1% Cu

Level 6 - Cu in quartzite, 0.2-1 m thick, Cu grade is low

Level 7 - Cu in red calcareous and dolomitic shale, 1-2 m thick, average 200-1000 ppm, local areas with average of 0.1-0.5% Cu.Selected samples with up to 6% Cu.Most widespread and persistentmineralisation.

Level 8 - Cu in dolomite or shale, Cu grade is low

Upper Eleonore Bay Supergroup

Lower Eleonore Bay Supergroup

Cu mineralised localities withinEleonore Bay Supergroup:

CanningLand

LyellLand

SuessLand

Ymer Ø

AndréeLand

StrindbergLand

26º

26º

72º72º

73º

N

Distribution of known Cu mineralisation within theEleonore Bay Supergroup, central East Green land.The different symbols refer to different mineralisedlevels in the Ymer Ø, Lyell Land and Nathorst LandGroups. Mineralised level number 7 is regarded asbeing the most widespread and persistent minerali-sation. Modified after Harpøth et al. 1986.

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Type of Cu

mineralisa-

tion

Reduced-facies Cu

Redbed Cu

Revett Cu

Volcanic Redbed Cu

Location

Central East

Greenland,

Jameson Land

Basin

North-East

Greenland,

Eleonore Bay

Supergroup

Central East

Greenland,

Jameson Land

Basin

North-West

Greenland,

Thule Basin

Central East

Greenland,

Jameson Land

Basin

North-East

Greenland,

Hekla Sund

Basin

Host rock

Black shales of the

Upper Permian

Ravnefjeld Formation

Silty mudstone of the

Upper Triassic Pingel Dal

Beds of the

Edderfugledal Member,

Fleming Fjord Forma tion

Calcareous and dolo -

mitic shales of the

uppermost part of the

Neoproterozoic Ymer Ø

Group

Grey and red interca -

lated mudstones of

playa flat origin of the

Upper Triassic Fleming

Fjord Formation

Pale sandstones of the

Meso- to Neoprotero -

zoic Qaanaaq Forma-

tion of the Baffin Bay

Group

Braided alluvial plain

conglomerate consisting

of well-rounded quartz -

ite, carbonate, granite

pebbles/cobbles in sand

and carbonate matrixes

of Upper Per mian

Huledal Forma tion

Shallow shelf sediments

of the Jyske Ås Forma -

tion of the Neopro tero -

zoic Hagen Fjord Group

Name of depo-

sit/occurrence

Vimmelskaftet

Devondal

Pingel Dal Beds

Ymer Ø Group

Nordenskiøld

Fleming Fjord

Formation

Olrik Fjord

‘Red Cliffs’

Rubjerg Knude

Ladderbjerg

Jyske Ås

Formation

Grades and size

Cu mineralisations are widespread in this area. Chip samples (n=39) over

20 m contains 200–850 ppm Cu, 1300–7000 ppm Pb and 350–1260 ppm Zn.

1-3 cm thick mineralised beds are known from several localities and contain

10% combined Zn and Pb.

Cu mineralisations are widespread in this area. A chip sample over 2.5 m

averages 200 ppm Cu, 200 ppm Pb and <500 ppm Zn.

A widespread and lateral persistent Cu mineralisation is known over an area

of 1000 km2. Thickness of mineralised horizons is between 0.2–2 m. Chip

samples (n=29) yield averages of 2000 ppm Cu over 1.1 m with a range of

200–5000 ppm Cu over 0.3–1.9 m.

A widespread and persistent Cu mineralisation extends for more than 275 km

from north to south. Thickness of mineralised horizons is from a few cm to a

few m. Average Cu content ranges from 2500 ppm to 15000 ppm with an

average content of 7000 ppm. Selected samples yield up to 6% Cu. The aver-

age Ag content is low with a Cu/Ag ratio of 1000–1500.

Cu mineralisations have been recorded continuously in 0.1–1 m thick sand-

stone beds over an area of 1000 km2. Chip samples from 21 sections (650 m

laterally) show an average content of 500 ppm Cu (from 27 to 3500 ppm)

and 1.3 ppm Ag (from 0.8 to 4.8 ppm) over a thickness of 0.38 m (from 0.25

to 0.6 m). Maximum values stem from a selected grab sample with 27.5%

Cu, 787 ppm Ag.

The Cu mineralisation is restricted to a 100 m2 area. A composite grab sample

shows 4000 ppm Cu.

Isolated outcrops of copper mineralised sandstone. Grab samples yields up to

1.5% Cu.

In some areas the Cu mineralisation extends over 20 m in thickness but in

average the thickness is between 5 m and 10 m. For an area of 1.3×2.5 km a

resource of 5 Mt with 3000 ppm Cu can be estimated (based on 13 chip sam-

ples).

Thickness of the Cu mineralisation is 10 m. A resource of 2.5 Mt with an esti-

mated grade of 1500 ppm Cu has been estimated for an area of 1×4 km. An

associated Pb mineralisation with an average thickness of 8 m is estimated to

contain 1.5 Mt with an estimated grade of 1% Pb (based on eight chip sam-

ples from the area).

Composite grab samples from the Jyske Ås Formation contain up to 3% Cu

and 100 ppm Ag.

Most important known sediment-hosted copper occurrences in Greenland

systems as illustrated by the Kupferschiefer-related Cu deposits in the Permian Zech -stein basin of Europe and the AfricanCopper Belt deposits in the NeoproterozoicKatangan basin. Also the Volcanic RedbedCu type can produce large deposits.

Sedimentary environments inGreenland

During the Proterozoic and throughout thePhanerozoic, major intercontinental-rift-related sedimentary basins formed in Northand North-East Greenland with sedimentarysuccessions reaching up to 18 km in thick-ness. Within Meso- to Neoproterozoic basins,

the most important sedimentary successionsfor copper deposits are the sediment-vol-canic succession of the Thule Supergroup ofthe Thule Basin in North-West Greenlandand the allochtonous, siliciclastic shelf andcarbonate platform successions of theEleonore Bay Supergroup in North-EastGreenland.The Thule Supergroup reaches a total

thickness of at least 6 km, possibly 8 kmand was deposited in an intracratonic frac-ture basin with block faulting and basinsagging formed in a divergent plate region.

The base of the basin is defined by anunconformity with underlying peneplainedbasement rocks. The sediments consist ofmulticoloured, mainly shallow-water, silici-clastic sediments with one interval of vol-canic rocks with basic sills at several levels.The depositional environment is continental(intertidal to subtidal) to lacustrine and shal-low marine with cratonic basaltic magma-tism.

The Eleonore Bay Supergroup comprisesa more than 14 km thick succession of shal-low-water sedimentary rocks, which accu-mulated in a major sedimentary basin thatevolved through a rapidly subsiding, silici-clastic shelf, a stable, siliciclastic shelf, car-bonate platform development and glaci -genic deposition. The basin is exposednorth-south for c. 450 km and east-west for c. 200 km. The early part of the succes-sion probably started out at palaolatitude c. 30°, whereas the late part of the succes-sion ended at c. 40°.The post-rift, thermal subsidence, sedi-

mentary successions of the Neoproterozoicfluvial to shallow marine sag deposits of theHagen Fjord Group of the Hekla Sund Basinin North-East Greenland may also have cop-per potential. This succession overlies the upto 1350 m thick well-preserved Mesopro -terozoic flood basalts of the Zig-Zag DalFormation. Late Palaeozoic and Mesozoic sedimen-

tary basins related to continental break-upwith formation of rift basins developedalong the continent-ocean margin in North,East and West Greenland. Most interestingfor sediment-hosted copper deposits are thePer mian and Triassic successions of theJameson Land Basin in East Greenland. TheUpper Permian rocks of the Jameson LandBasin consist of an up to 180 m thick suc-cession of non-marine conglomerate,

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The carbonate buildups of the Wegner Halvø Formation and the overlying black shales of theRavnefjeld Formation, central East Greenland. Photo towards north-west, with Fleming Fjord in thebackground and the western part of the peninsula Wegner Halvø in the foreground. The cliff face isc. 400 m high. Photo: Mikael Pedersen.

View of the Ladderbjerg Cu deposit within the Huledal Formation, central East Greenland. Photo: Bjørn Thomassen.

Ravnefjeld Formation

Schuchert Dal Formation

Wegner Halvø Formation

Huledal Formation

Fleming Fjord Formation

Fleming Fjord

Carbonate buildups

marine sandstone and shale and carbonateplatform sediments including evaporites andalgal-laminated gypsum. The shales haveattracted considerable attention due to theirhigh potential as hydrocarbon source rock.The Triassic succession consists of a c. 1700m thick sequence of shallow marine to con-tinental and lacustrine clastics with interca-lations of evaporites and thin carbonates.

Known sedimentary hosted cop-per occurrences

Very limited exploration for sediment-hostedcopper mineralisation has been carried outin Greenland. Only a few occurrences havebeen investigated in detail to a level whichallows for qualified estimates of overall ton-nage and grade.

Reduced-Facies Cu occurrencesIn central East Greenland, within the Jame -son Land Basin, Reduced-facies Cu depositsare known from both Upper Permian andUpper Triassic strata. The copper mineralisa-tion within the black shales of the Ravne -fjeld Formation is widespread and has beencompared with the European Kupferschiefertype. Copper mineralisation within theTriassic strata of the Jameson Land Basin isknown from several levels. The most pro-nounced and promising deposit is theReduced-facies Cu-type mineralisationfound within cyclically bedded sandstone,siltstone and mudstone of the Upper TriassicPingel Dal Formation of the EdderfugledalMember, Fleming Fjord Formation. In North-East Greenland, within the Neo -

proterozoic Eleonore Bay Supergroup (EBS)eight levels of stratiform and strataboundCu mineralisation have been observed. Thisobservation has been made within a 3 kmthick stratigraphical pile of the uppermostthree stratigraphical groups of the fourgroups that make up the EBS. The mostwidespread and persistent level of minerali-sation occurs within the lowermost part ofthe Ymer Ø Group. Genetically, the mineral-isation is interpreted to be syn-sedimenen-tary to early diagenetic in origin and proba-bly best represents a Reduced-facies Cu-type mineralisation. Algal mounds andpseudomorphed evaporites adjacent to the

mineralised Cu level within the lowermostYmer Ø Group may have played an impor-tant role in the formation of reducer brines.Also, the lowermost part of this Group wasinduced by a major transgressive event, pos-sibly accompanied by a shift to more aridclimate. Most Reduced-facies Cu depositsare formed during such trangressions ofreduced marine sediments over redbeddeposits. The mineralisation shows similari-ties with part of the Zambian copper belt

and the Precambrian Belt Supergroup inIdaho and Montana. The mineralisation alsodisplays similarities with Cu deposits in theNeoproterozoic Adelaidean Sequence of theStuart Shelf, South Australia.

Redbed Cu occurrencesCopper mineralisations are found through-out the Triassic stratum in the Jameson LandBasin, central East Greenland. Redbed Cu-type mineralisations occur within the Ørsted

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Geologist inspecting the mineralised conglomerate of the Ladderbjerg Cu deposit in the HuledalFormation, central East Greenland. A resource of 2.5 Mt with a grade of 1500 ppm Cu has beenestimated for an area of 1×4 km (based on eight chip-sampled sections of the 8–10 m thick con-glomerate). Photo: Bjørn Thomassen.

Dal and Malmros Klint members of theUpper Triassic Fleming Fjord Formation. Thecopper occurrences are hosted in two ormore 0.1 to 1 m thick, grey, pale-yellowishweathering beds intercalated with red mud-stones. Thin intraformational breccias, sep-tarian nodules and plant fragments up to30 cm long occur locally.The entire stratigraphical succession of

the Meso- to Neoproterozoic ThuleSupergroup hosts redbed units in abun-dance. It is estimated, that redbed succes-sions form 20 to 55% of the total strati-graphical thickness in four out of the fiveformations that constitute the Thule Super -group. This means that redbed successions,depending on their position in the basin,

make up from 0.5 to 1.9 km of the totalsedimentary package of the basin. There isgood evidence for long, extensive fluid/brine activity within the basin; and blockfaulting associated with half-graben struc-tures may have provided the important frac-ture-permeability and hydrologic setting todrive the process of fluid mixing needed toform the Redbed Cu-type mineralisation.This is also reflected by the distribution ofknown Redbed Cu occurrences within theThule Supergroup, which all are adjacent tothe major faults.

Revett Cu occurrencesScattered, stratabound copper occurrencesare known from the Upper Permian sandy

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R E S O U R C E A S S E S S M E N T S

The black shale of the Upper Permian Ravne -fjeld Formation on Wegener Halvø is a knownhost of Reduced-facies Cu-type mineralisationin central East Greenland. Maximum valuesfrom grab samples show 11.5% Zn, 7.7% Pband 0.35% Cu. Photo: Bjørn Thomassen.

Thick, silty, multicoloured mudstones from theUpper Triassic Pingel Dal Beds of the Edder -fugledal Member, Fleming Fjord Formation ofthe Jameson Land Basin in central East Green -land. The cliff face is 50 m high. Widespreadand laterally persistent Reduced-facies Cu-typemineralisation occurs within the beds over atleast 1000 km2. Photo: Bjørn Thomassen.

conglomerates of the Huledal Formation ofthe Jameson Land Basin, central EastGreenland. Two of these occurrences arelarge enough to have been subjected toestimates of tonnage and grades. TheHuledal Formation belongs to the marineFoldvik Creek Group which was depositedunconformably mainly on extremely flatCarboniferous – Lower Permian peneplain.The formation is up to 120 m thick withgreat thickness variation. The formationconsists of poorly sorted, immature fluvialconglomerate beds, sandstone sheetdeposits and some mudstones. The con-glomerate constitutes a high pre-ore perme-able bed. Parts of the Upper Permian suc-cession are bituminous-bearing and areregarded as a good source rock for hydro-

9

Alluvial fans, braided rivers

Floodplains

Dunes

Shallow marine bay

Playa lake with gypsum

Playa lake with stromatolites

Playa mudflats

Shallow carbonate lakes

Cu, Pb, Zn mineralisation*

**

**

**

Ta

Se

GkKl

Pa

NW SE

10 km

Triassic Mineralisation, central East Greenland

The 700 m high cliff face at Buch Bjerg consistingof Upper Triassic sediments of the Fleming FjordFormation (red sediments near the top of the cliff),Gipsdalen Formation (the paler red to grey part)and the Pingo Dal Formation (the underlying pink-ish sediments) of the Jameson Land basin. TheTriassic succession hosts several several knownReduced-facies and Redbed Cu-type mineralisa-tions. Photo: Asger K. Pedersen.

Generalised facies pattern and mineralisation of the Upper Triassic Pingo Dal, Gipsdalen and FlemingFjord Formations. Kl = Klit Dal Member, Pa = Paradigmabjerg Member, Gk = Gråklint Beds, Se =Kap Seaforth Member, Ed = Edderfugledal Member (including Pingel Dal Beds), Ma = Malmros KlintMember, Ør = Ørsted Dal Member, Ta = Tait Bjerg Beds. After Harpøth et al. 1986.

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carbon potential. At central Trail Ø, theRubjerg Knude Cu deposit occurs withinconglomerates of the Huledal Formation,which is 30–60 m thick here. Central Trail Øis dominated by block faulting, which mayhave played an important role as the fluidpathway in the formation of the mineralisa-tion. Above the conglomerate unit occurs a50 m thick sandstone unit, which is overlainby a 10 m thick sabkha unit containing fine-grained gypsiferous sandstones and gypsumbeds. This unit is followed by a complexunit that represents the erosional plateauwith a variety of sandstones, siltstones,shales and various carbonate rocks. Themineralisation is associated with palaeo -channels within the conglomerate unit.

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The metabasalts of the Mesoproterozoic Zig-Zag Dal Formation (red brownish-blackish suc-cession) with the overlying sandstones of theNeoproterozoic Jyske Ås Formation (palebrownish succession) exposed on the west cliffface of Neergaard Dal, eastern I.C. ChristensenLand, North-East Greenland. The cliff face is400–500 m high and the valley is 4–5 kmwide. Photo: Bjørn Thomassen.

Malachite-stained, elongated zone within palesandstone surrounded by red sandstone of theJyske Ås Formation. The zone appears to bestructurally controlled. Photo: Bjørn Thomassen,Avannaa Resources Ltd.

Landsat TM colour composite draped on a digi-tal elevation model. Indications of known Cuoccurrences within the Neoproterozoic Jyske ÅsFormation along the N–S-oriented valleyNeergaard Dal on eastern I.C. ChristensenLand, North-East Greenland, can be seen onthe image. The image is seen from the north.No vertical exaggeration.

Hagen Fjord

Independence Fjord

Cu occurence

Bitumen content between mineral grains isobserved. The mineralisation is believed tobe of the Revett Cu type. Still in the HuledalFormation, but farther north, scattered stra-tabound Cu occurrences are found, wherethe formation has an average thickness of10 m. The most significant of these beingthe Ladderbjerg Cu deposit, which is morethan 10 m thick in an area of 1×4 km.

Volcanic Redbed Cu occurrencesNo firmly established Volcanic Redbed Cuoccurrences are known from Greenland.However, Cu deposits have been found inNorth-East Greenland that may be candi-dates for this type of occurrence. Theseoccur within the Neoproterozoic, post-rift,thermal subsidence sediments of the lowerpart of Hagen Fjord Group of the HeklaSund Basin, which overlies the well-pre-served Mesoproterozoic flood basalts of theZig-Zag Dal Formation.The copper occurs both as native copper

and copper-sulphides. An elongated natureof the Cu occurrences suggests a relation-ship with graben faults and structureswhich may play an important role for thetransportation of the mineralising fluids.

Potential areas for undiscoveredcopper deposits

At the ‘Workshop on the Potential forUndiscovered Sedimentary Hosted CopperDeposits in Greenland’ the members of theassessment team gave their bids on differ-ent confidence levels on how many copperdeposits they thought could be discoveredunder the best circumstances. The distribu-tion of undiscovered copper deposits on thedifferent confidence levels as well as theincrease in numbers from one confidencelevel to another reflect the level of knowl-edge about the various areas and the over-all feeling about the potential within theareas. In general the assessment team agreed

that the biggest potential for large-grade-tonnage deposits of the Reduced-facies Cutype was within the Neoproterozoic Eleo -nore Bay Supergroup in North-East Green -land and the Upper Triassic Pingel Dal Bedsof the Fleming Fjord Formation in centralEast Greenland. Also the Hagen FjordGroup in North-East Greenland was regard-ed as having a large potential for depositsof the Volcanic Redbed Cu type.

Concluding remarks

Greenland represents a region for grass-rootexploration with great potential for sedi-ment-hosted copper mineralisations. Manysedimentary successions in Greenland areconsidered favourable and bear evidence ofthe mineralising processes needed to form acopper deposit. This is also reflected in themany known copper mineralisations discov-ered in all the sedimentary successions.However, in most cases only limited explo-ration campaigns have been carried out andonly a few occurrences have seen detailedinvestigations. Especially interesting are theunderexplored parts of the successions ofthe Eleonore Bay Supergroup in North-EastGreenland and the Upper Permian andTriassic sediments in central East Greenland.They host known as well as have furtherpotential for the important Reduced-faciesCu-type mineralisations in Greenland.

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1Type of Cu Region Area Tract name Areal extent Number of undiscovered Cu depositsmineralisation on di�erent con�dence levels N90 N50 N10 N05 N01

Permian Ravne�eld Formation CE-2, 4–15 2250 km2 0 0 0 0 2 Central East Greenland Triassic Pingel Dal Beds CE-1 A 2000 km2 0 0 0 2 4 Triassic Pingel Dal Beds CE-1 B 1000 km2 0 0 0 0 2Reduced-facies Cu Neoproterozoic Eleonore Bay Supergroup CE-1–6, CE-9–16 2111 km2 0 0 0 1 4

North-East Greenland Neoproterozoic

Eleonore Bay Supergroup CE-7–8 1000 km2 0 0 0 2 4 Permian Huledal Formation CE-2 436 km2 0 0 0 1 2 Permian Huledal Formation CE-4–7 882 km2 0 0 0 1 3Revett Cu Central East Greenland Permian Huledal Formation CE-8–12 449 km2 0 0 0 2 4 Permian Huledal Formation CE-13–14 361 km2 0 0 0 1 3 Permian Huledal Formation CE-15 165 km2 0 0 0 0 1 Triassic Fleming Fjord Form. CE-1 A 2310 km2 0 0 0 2 4 Central East Greenland Triassic Fleming Fjord Form. CE-1 B 1150 km2 0 0 0 0 2 Meso- to Neoproterozoic Redbed Cu Ba�n Bay Group NW-1–2, NW-5–10 5740 km2 0 0 0 2 5 Meso- to Neoproterozoic

North-West Greenland Narssârssuk Group NW-3–4 320 km2 0 0 0 0 2

Meso- to Neoproterozoic Smith Sound Group NW-11–13 1230 km2 0 0 0 2 4 Neoproterozoic Hagen Fjord Group NE-1–9 15,000 km2 0 0 2 3 6Volcanic Redbed Cu North-East Greenland

Neoproterozoic Hagen Fjord Group NE-10–11 5810 km2 0 0 0 1 3

N90–N01 = confidence level; a measure of how reliable a statistical result is, expressed as a percentage that indicates the probability of the result being correct. A confidence

level of 10% means that there is a probability of at least 10% that the result is reliable.

Consensus bids on the number of undiscovered Cu deposits per area

12

Cox, D.P. 1986: Descriptive Model of Basaltic Cu.

In: Cox, D.P. & Singer, D.A.(eds): Mineral Deposit

Models, U.S. Geological Survey, Bulletin 1693, p.

130.

Cox, D.P., Lindsey, D.A., Singer, D.A. & Diggles

M.F. 2003: Sediment-Hosted Copper Deposits

of the World: Deposit Models and Database, U.S.

Geological Survey, USGS Open-File Report

2003–107, 41 pp.

Dawes, P.R. 2006: Explanatory notes to the

Geological map of Greenland, 1:500 000, Thule,

Sheet 5. Geological Survey of Denmark and

Greenland Map Series 2, 97 pp. + map.

Ghisler, M., 1994:Ore minerals in stream sediments

from North Greenland. Open File Series Grønlands

Geologiske Undersøgelse 94/17, 46 pp., one

1:500.000 geological map, 7 maps.

Harpøth, O., Pedersen, J. L., Schønwandt, H.

K. & Thomassen, B. 1986: The mineral

occurrences of central East Greenland. Meddelser

om Grønland Geoscience 17, 138 pp., 1 plate.

Kirkham, R.K. 1996: Volcanic redbed copper. In:

Eckstrand, O.R., Sinclair, W.D. & Thorpe, R.I. (eds):

Geology of Canadian Mineral Deposit Types,

Geological Survey of Canada, Geology of Canada

8, 241–252.

Moeri, E. 1975: 6/75. Preliminary report of 1975

activities. Stratabound copper indications in the

Precambrian Eleonore Bay group of central East

Greenland. Internal report, Nordisk Mineselskab

A/S, 41 pp. ( in archives of Geological Survey of

Denmark and Greenland, GEUS Report File

20775).

Smith, S. J. H. & Campbell, D. L. 1971: The

geology of Greenland north of latitude 74°30'N.

Report no. 2. Volume 2. Mineral prospects of

northern Greenland. Internal report, Ponderay

Polar A/S, 62 pp. (in archives of Geological Survey

of Denmark and Greenland, GEUS Report File

20811).

Stendal, H. & Ghisler, M. 1984: Strata-bound

copper sulfide and nonstrata-bound arsenopyrite

and base metal mineralization in the Caledonides

of East Greenland – a review. Economic Geology

79, 1574–1584.

Thomassen, B., Nyegaard, P., West, N. &

Fritzenwanker, J. 1975: 8-9/74. Prospecting

report 1974. Stratabound permo-triassic copper-

lead-zinc- mineralizations at the eastern border

of the Jameson Land Bassin. Internal report,

Nordisk Mineselskab A/S. Vol. 1, 98 pp., 21

photos. Vol. 2 (in archives of Geological Survey

of Denmark and Greenland, GEUS Report File

20658).

Thomassen, B. & Nilsson, B. 1982: 1/81.

Prospecting for Cu-Pb-Zn-Au-Ag in the Clavering

Ø, Giesecke Bjerge and Canning Land areas.

Internal report, Nordisk Mineselskab A/S, 59 pp.,

1 app., 8 plates, 17 photos. (in archives of

Geological Survey of Denmark and Greenland,

GEUS Report File 20703).

Thomassen, B., Clemmensen, L. B. & Schøn -

wandt, H. K. 1982: Stratabound copper-lead-

zinc mineralisation in the Permo-Triassic of central

East Greenland. Bulletin Grønlands Geologiske

Undersøgelse 143, 42 pp.

Front cover photographCu-mineralised conglomerate of the

Revett Cu type at the Ladderbjerg Cu

deposit in the Permian Huledal For -

mation, Jameson Land Basin, central East

Greenland. Photo: Bjørn Thomassen.

Bureau of Minerals and Petroleum(BMP)

Government of GreenlandP.O. Box 930DK-3900 NuukGreenland

Tel: (+299) 34 68 00Fax: (+299) 32 43 02E-mail: bmp@nanoq.glInternet: www.bmp.gl

Geological Survey of Denmark and Greenland (GEUS)Øster Voldgade 10

DK-1350 Copenhagen KDenmark

Tel: (+45) 38 14 20 00Fax: (+45) 38 14 20 50E-mail: geus@geus.dkInternet: www.geus.dk

AuthorBo Møller Stensgaard, GEUS

EditorsLars Lund Sørensen & Jane Holst,

GEUS

Graphic ProductionHenrik Klinge Pedersen, GEUS

PhotographsGEUS unless otherwise stated

PrintedJanuary 2011 © GEUS

PrintersRosendahl/Schultz Grafisk

ISSN1602-818x

Olrik Cu mineralisation within the Qaanaaq Formation in the Thule Basin, North-West Greenland (thegreen malachite-stained patch in the foreground of the hill). The mineralisation is adjacent to twomajor faults of the Olrik half-graben structure.The mineralisation covers an area of 100 m2 Photo: BjørnThomassen.

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