New Understanding and mineral endowment of the Archaean, Palaeoproterozoic and Palaeogene of South-East Greenland

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Palaeogene of South-East Greenland Bo M.

1 Greenland Day Perth, Dec. 9 th, 2015 New Understanding and mineral endowment of the Archaean, Palaeoproterozoic and Palaeogene of South-East Greenland Bo M. Stensgaard & Jochen Kolb Department of Petrology and Economic Geology Geological Survey of Denmark and Greenland (GEUS) with acknowledgement and contributions from members of the SEGMENT project

2 Where are we? South-East Greenland; access point to East Greenland Situated close to Iceland - between North American and European markets Well-connected with Iceland Tasiilaq; fully serviced Atlantic harbor Daily (summer) flights to Iceland Northern area; many smaller settlements Southern area; remote Mountainous, long valleys, deep fjord systems no infrastructure Possibilities for hydropower solutions Large sources of fresh water No conservation areas, national parks or private land owners

3 3.400 million years of geology - what constitute South-East Greenland? Two Archaean cratons Multiple deformation and metamorphic orogenic events Large Archaean mafic to alkaline intrusive suite Palaeoproterozoic collisional orogen Large magmatic arc intrusives Belts of Palaeoproterozoic metasedimentary and metavolcanic rocks Large post-orogenic intrusive complexes Palaeogene break-up of the North Atlantic recent intrusions and volcanic rocks NAC RAE Craton

4 Cratons and orogens Central located in a collage of cratons and orogens North Atlantic Craton Nagssugtoqidian Orogen Ketilidian Orogen Global distributions of the cratons (crust >2.5 Ga old); modified after Bleeker (2003)

The basement the beating hearth of the Archaean

banded; basement fragments Age: > 2850 Ma 3450 Ma(?

belts of paragneiss and mafic--ultramafic rocks

5-9 kbar Mafic granulite: ~ 800 C; 5-8 kbar ±

granulite facies: HFSE depleted Infiltrated by

of the North Atlantic Craton to the Skjoldungen

5 The basement the beating hearth of the Archaean Thrym Complex: Dominated by poly-phase; migmatitic, banded; basement fragments Age: > 2850 Ma 3450 Ma(?) up to 1 km wide and several 10s of km extending belts of paragneiss and mafic--ultramafic rocks Paragneiss: C; < kbar Mafic granulite: ~ 800 C; 5-8 kbar ± peridotite/pyroxenite Partial melt at peak granulite facies: HFSE depleted Infiltrated by melts Model for the formation of the basement rocks of the North Atlantic Craton to the Skjoldungen Orogeny Bagas et al Mid- to deep Archaean crust Products of crustal melting and major thermal events

Mineral endowment: Lommen Jættefjord Ni Cu Orthomagmatic Ni Cu mineralisation in ultramafic rocks Mafic and ultramafic layers locally contains pods and layers of Ni-

Up to 0.5% Ni, 0.25% Cu; Pt 24 ppb, Pd 162, Cr 0.5% Tonnage to small; discontinuous still potential Owen 2012, Rennich 2012, Kolb et al. 2012, Bagas et al.

6 Mineral endowment: Lommen Jættefjord Ni Cu Orthomagmatic Ni Cu mineralisation in ultramafic rocks Mafic and ultramafic layers locally contains pods and layers of Ni- Cu sulphide mineralisation Interstitial to net-textured sulphides Po, Ccp, Pn; up to 20%, or as disseminated sulphides 1-2 m thick layers, several km along strike. Up to 0.5% Ni, 0.25% Cu; Pt 24 ppb, Pd 162, Cr 0.5% Tonnage to small; discontinuous still potential Owen 2012, Rennich 2012, Kolb et al. 2012, Bagas et al. (submitted) Pyroxenite Peridotite Ni-Cu mineralised zones Owen 2012 Mafic-ultramafic Ni-Cu mineralised bands (ountlined in green) at Kangerdlikajik Fjord. Cliff-wall 600 m Rennich 2012

Deep-seated muscles of the Archean multiple deformation events 0

and metamorphism Regional transtension Singertat stage Exhumation until

Brittle deformation, mafic dykes Kolb et al.

7 Deep-seated muscles of the Archean multiple deformation events 0 Regional compression until 2.7 Ga Timmiarmiut Orogeny; 3.45 Ga grains Regional extension Ga Skjoldungen Orogeny; collision/subduction Penetrative foliation and metamorphism Regional transtension Singertat stage Exhumation until 2.7 Ga Ketilidian Orogen & Gardar rifting Opening of the North Atlantic Brittle deformation, mafic dykes Kolb et al Collisional orogen Images from The Essential Earth (Jordan & Grotzinger, 2008) erosion level Thrym Complex Archaean South-East Greenland

A rarity of the Archaean Skjoldungen alkaline-mafic province (SAP)

Outcrops along 80 x 30 km NW-SE trending belt Ultramafic mafic felsic

diorites, - Monzonites, syenites, granites - Late nephelinitic &

intrusions Subduction-modified primitive mantle source metasomatised

8 A rarity of the Archaean Skjoldungen alkaline-mafic province (SAP) Archaean ( Ma) alkaline-mafic province (rare worldwide) Outcrops along 80 x 30 km NW-SE trending belt Ultramafic mafic felsic intrusions - Pyroxenites, hornblendites, - Hbl norites, gabbronorites, diorites, - Monzonites, syenites, granites - Late nephelinitic & carbonatite rocks Geochemical subduction affinity Syn- to post-tectonic intrusions Subduction-modified primitive mantle source metasomatised mantle melting Derived magmas involving primitive mantle Kokfelt et al. (in press) Skjoldungen intrusives

9 Skjoldungen alkaline-mafic province (SAP) Kokfelt et al. (in press), Næraa et al. (in preb.) Three magmatic pulses: Last 2631 Ma; pegmatites Young pulse; around 2695 Ma gabbro, gabbronorite, diorite, nephelinitic and carbonatite rocks Middle pulse; around 2713 Ma granite, diorite, syenite Old pulse; around 2744 Ma syenite, syenitic gneiss Carbonatiticnephelinitic sheet 2.6 Ga Singertât Complex Syenite with variably dissolved mafic xenoliths Layered gabbro complex Granite-asyenite Omat Vend Sfinksen

10 Mineral endowment: Vend Om Gabbro Concordant magnetite rich band in Layered Series Magnetite-rich band within the layered gabbro sequence: Up to 1.5m thick over ca 50 m lateral distance, thinning out Marupgaard 2015, Kolb et al. 2015, Kokfelt GEOLOGICAL et al. (in press) SURVEY OF DENMARK AND GREENLAND Magnetite-rich band, locally with sulphides

Mineral endowment: Rhythmical modal layering in Vend Om V Ti Fe potential in

magnetite-rich layers; massive to disseminated discovered in three layered

7 wt% V 2 O 5 However; Grades not high Small tonnage, tectonized No PGE, Au

Leuco-gabbro xenolith depressing layer in Vend Om Gabbro Vend Om Gabbro

11 Mineral endowment: Rhythmical modal layering in Vend Om V Ti Fe potential in layered intrusions Magnetite-rich bands in layered mafic Intrusions Several magnetite-rich layers; massive to disseminated discovered in three layered gabbroic and dioritic intrusions. V-Ti-Fe potential; up to 1.7 wt% V 2 O 5 However; Grades not high Small tonnage, tectonized No PGE, Au encountered still possibilities Hermods Vig Diorite Dropstone structure. Leuco-gabbro xenolith depressing layer in Vend Om Gabbro Vend Om Gabbro Layered Series bifurcating layer (similar to the famous Dwars River location, Bushveld) at Vend Om Iglermiut Gabbro

6% W; 263 ppm Mo Re-Os dating: 2749±11 Ma old SAP pulse; monzogranite and Skirner Bjerge

12 Mineral W Mo endowment: Quartz wolframite molybdenite vein & scheelite in amphibolite Quartz-wolframite-molybdenite vein C. 30 cm wide, subvertical hosted in mafic granulite 1.6% W; 263 ppm Mo Re-Os dating: 2749±11 Ma old SAP pulse; monzogranite and Skirner Bjerge Syenite Scheelite in amphibolite Up to 0.55% W Believed to be contemporaneous with the dated vein Rosa & Ulrich 2013

13 3.400 million years of geology - what constitute South-East Greenland? Two Archaean cratons Multiple deformation and metamorphic orogenic events Large Archaean mafic to alkaline intrusive suite Palaeoproterozoic collisional orogen Large magmatic arc intrusives Belts of Palaeoproterozoic metasedimentary and metavolcanic rocks Large post-orogenic intrusive complexes Palaeogene break-up of the North Atlantic recent intrusions and volcanic rocks NAC RAE Craton

Palaeogene Intrusive Suite Palaeoproterozoic collisional orogen between the Rae and the

RAE Craton Thrym Complex AIC Nagssugtoqidian Orogen South-East Greenland Archaean

to south into the: Schweizerland Terrane; thrusted on top of terrane to the south,

facies; 1820 Ma decompression to amphibolite facies; migmatitic orthogneiss (ages between)

quartzite and lesser amphibolites and ultramafic rocks.

amphibolites, ultramafic Archaean orthogneiss and 1937±7 Ma banded orthogneiss.

14 Palaeogene Intrusive Suite Palaeoproterozoic collisional orogen between the Rae and the North Atlantic craton Schweizerland Terrane Kuummiut Terrane Isortoq Terrane NAC Craton? RAE Craton Thrym Complex AIC Nagssugtoqidian Orogen South-East Greenland Archaean orthogneisses deformed during the collision; basement ~ Ma Subdivided from north to south into the: Schweizerland Terrane; thrusted on top of terrane to the south, granulite facies, mainly Ma orthogneiss Kuummiut Terrane; 1867±28 Ma eclogite facies; 1820 Ma decompression to amphibolite facies; migmatitic orthogneiss (ages between) Ma) with doubly folded supracrustal belts paragneiss, graphitic schist, marble, quartzite and lesser amphibolites and ultramafic rocks. Ammassalik Intrusive Complex (AIC); 1885 Ma, magmatic arc related complex Isortoq Terrane; amphibolites, ultramafic Archaean orthogneiss and 1937±7 Ma banded orthogneiss. Large post-tectonic intrusive complexes; ~ 1665 to 1525 Ma, diorite, granodiorite, gabbro, granite Palaeogene intrusive suite including volcanics and dolerite dyke

15 Niflheim thrust Supracrustal units of the Kuummuit Terrane

16 Niflheim Thrust; Archaean orthogneisses in amphibolite (footwall) and in granulite facies (hangingwall); 2733±5Ma and 2705±15Ma respectively. ~

18 Palaeoproterozoic graphitic schist, paragneiss and marble; 1 wide belt north of Heilheim Gletcher. Marble and graphitic schist from the air

19 Complex history with nappe formation, large domes and synformal

20 Large scale isoclinal folding

Mineral endowment: Graphite Graphite mineralisation in schist Graphite within meta-pelite/-schist units within the supracrustal is widespread Within certain horizons and structural controlled

% graphitic carbon) Uninvestigated graphite occurrences are present in between Strong supergene alteration; loose limonite gravel, which contains graphite flakes as a main component.

21 Mineral endowment: Graphite Graphite mineralisation in schist Graphite within meta-pelite/-schist units within the supracrustal is widespread Within certain horizons and structural controlled zones these approach ore grade Two areas have been studied in detail, Auppaluttoq and two at Kangikajik (<30 wt.% graphitic carbon) Uninvestigated graphite occurrences are present in between Strong supergene alteration; loose limonite gravel, which contains graphite flakes as a main component. One area being km. Flakes up to 6 mm; average of 3.33 mm ± 1.21 mm Most likely hydrothermal deposited graphite Rosing-Schow et al Supergene limonite alteration zone in central Auppaluttoq. The zone is approximately 300 m wide and surrounded by orthogneiss. Rosing-Schow et al

Geochemistry 2010 190 ppb Au in stream sediment geochemistry

1 ppm Graphitegarnet-gneiss 1.1 ppm 5.2 ppm Amphiibolite 7.

22 Mineral endowment: Gold[?] Former exploration results Ujarassiorit results SEGMENT Geochemistry ppb Au in stream sediment geochemistry GEUS-MMR Au>1ppmfieldwork 1.1 ppm 15.2 ppm Qtz w. pyrite 10.6 ppm Qtz w. pyrite 2 ppm MMR-GEUS Stream Sediment Geochemistry ppm Graphitegarnet-gneiss 1.1 ppm 5.2 ppm Amphiibolite 7.5 ppm Amphibolite 14.7 ppm 20 ppm Qz-vein 2.5 ppm 40 km Ujarassiorit results , Au above 50 ppb with indications of those above 1 ppm Au (both float and bedrock; locations uncertain)

Mineral endowment: Gold[?] Quartz veins with elevated gold; Ujarassiorit samples; [?] Follow-up on Ujarassiorit by GEUS- MMR; 11 g/t Au at Auppaluttoq confirmed occurrences of anomalous gold (0.

23 Mineral endowment: Gold[?] Quartz veins with elevated gold; Ujarassiorit samples; [?] Follow-up on Ujarassiorit by GEUS- MMR; 11 g/t Au at Auppaluttoq confirmed occurrences of anomalous gold (0.5 g/t) within quartz-veins Other anomalous areas (floats) were not confirmed. More potential targets are present A GEUS-MMR targeting exercise is ongoing Gold seems to be hosted in quartz-vein systems within supracrustals; these are very weathered and appear as rustygossans. A gold potential is present; but more detailed field campaigns are wanted e.g. detailed large rock and soil-sampling program investigations of weathering; leaching of metals under Arctic conditions Poulsen et al The local Ujarassiorit 1 st prize winner William Umerineq at the Auppaluttoq site where he samples 11 g/t Au. GEUS-MMR were not able to replicate this; but picked-up 0.5 g/t Au in quartz-veins from the site. Nugget-effects may be causing this and only limited work have been carried out on the site.

25 Anorthosite enclaves in migmatitic orthogneiss Granite invaded orthogneiss

26 Large ultramafic lens, followed by granite and with amphibolite sequence in the background

27 Mineral endowment: Ruby Ruby sapphire in metasomatic alteration zones Follow-up on Ujarassiorit winning ruby sample by GEUS-MMR revealed several ruby occurrences in the area Same characteristics: ruby-sapphire occurs where late-stage felsic pegmatites crosscut and metasomatically interact with metamorphosed ultramafic rocks. Progressive metasomatic replacement of the pegmatite takes place with welldeveloped mineral zoning, culminating in a biotite zone, followed by a zone with black amphibole + pink to purple rubysapphire. Ruby-sapphire is rare, but large (locally up to 5 cm in diameter), anhedral in shape with only little fractures. The genetic model works; new discoveries made, however more work is needed; potential for larger systems? Metasomatic reaction band in ultramafic rock with concentric mineral zones; core zone consists of pure biotite, locally enveloping a black amphibole + purple ruby zone. Poulsen et al. 2013; Poulsen & Hinsberg 2014; Poulsen et al

29 Ammassalik Intrusive Complex: Diorite of ~1885 Ma Contact metamorphic aureole of diatexites

30 Supracrustals and diatexites in the contact aureole

2014 GEUS-CET-BMP work Conduit-type model; orthomagmatic New discovery of semi-massive sulphide

31 Mineral endowment: Ni Cu PGE Orthomagmatic Ni Cu PGE mineralisation in AIC Earlier discoveries by NunaOil A/S in the anatectic supracrustal zone outside the AIC; komatiite-nickel exploration model A GEUS-CET-BMP work Conduit-type model; orthomagmatic New discovery of semi-massive sulphide mineralisation within gabbro-norite-tonalite of the AIC A. GEOLOGICAL SURVEY Johansen OF DENMARK (in preb.), Kolb AND et al. GREENLAND 2015

33 Peaks of the Ammassalik Batholith; granite, granodiorite, diorite, norite, gabbro Diorite 1634±14 Ma

34 ~1600 Ma granite intrusion

35 3.400 million years of geology - what constitute South-East Greenland? Two Archaean cratons Multiple deformation and metamorphic orogenic events Large Archaean mafic to alkaline intrusive suite Palaeoproterozoic collisional orogen Large magmatic arc intrusives Belts of Palaeoproterozoic metasedimentary and metavolcanic rocks Large post-orogenic intrusive complexes Palaeogene break-up of the North Atlantic recent intrusions and volcanic rocks NAC RAE Craton

36 Palaeogene Intrusive Suite Schweizerland Terrane RAE Craton Palaeogene intrusive suite Kialineq District, Kap Gustav Holm 50 Ma old gabbro and a comparatively young suite of intrusions (40-35 Ma) dominated by dioritic to syenitic and granitic compositions. No discovered mineralisation; although a conceptual potential for magmatic Au-PGE may or exhalative/ hydrothermal mineralising systems may be presents Map after Brooks 2011 Younger granites in Skrækkens Bugt Diorite by cut by pink syenitic veins in Skrækkens Bugt

Overall purpose SEGMENT; South-East Greenland Mineral ENdowment Task An interesting geological model unfolds for entire South-East Greenland The Tasiilaq and, perhaps to a lesser extend the

37 Overall purpose SEGMENT; South-East Greenland Mineral ENdowment Task An interesting geological model unfolds for entire South-East Greenland The Tasiilaq and, perhaps to a lesser extend the Skjoldungen region comprise a potential for different mineral resources The ongoing work by GEUS and MMR will continue into 1 st half of 2016 with more results pending Final mineral endowment report and a digital GIS data package to be presented early 2016 A likely workshop including summary of new model and data will be announced in 2016 Stream sediment geochemistry and indicator mineral data as well as new regional aeromagnetic data are already available Few licenses are currently claimed in the region; interested in knowing more come and talk with us

38 Greenland Day Perth, Dec. 9 th, 2015 Thank you For more information, please contact Bo M. Stensgaard (bmst@geus.dk)

39 the end...

lowermost part of the crust Peridotite Leucosome Green peridotite and black pyroxenite;

40 Mineral endowment: Lommen Jættefjord Ni Cu Orthomagmatic Ni Cu mineralisation in ultramafic rocks Layers of ultramafic and mafic granulites Interpreted to be intrusions in the lowermost part of the crust Peridotite Leucosome Green peridotite and black pyroxenite; mingling. Mafic granulite Sequence of peridotite, pyroxenite, mafic granulite and Ni-Cu mineralisation

56 pct AIC contact Qorqortoq Showing 425m The Main Mineralisation Discovered 1996 by NunaOil/NunaMinerals A/S concordant lens trending 310º and dipping 70º NE; Isocline fold axis

41 Mineral endowment: Ni Cu PGE Orthomagmatic Ni Cu PGE mineralisation in AIC Polheim Showing Main Mineralisation 1.39 pct Cu Co 0.46 pct 757 ppm Au Pd 108 ppb Pt 29 ppb 21stNorth 219 ppb NiTenor CuTenor800m TASIILAQ New Showing Ni 4.72 pct Polheim Showing 1.56 pct AIC contact Qorqortoq Showing 425m The Main Mineralisation Discovered 1996 by NunaOil/NunaMinerals A/S concordant lens trending 310º and dipping 70º NE; Isocline fold axis plunging 127º/38º Hosted in partly serpentinised ultramafic rock - discontinuous rusty lineament ultramafic pods or boudins parallel to the contact of the AIC m on surface and varies in width from 1 to 8 m; NiTenor 4.72%, CuTenor 1.56% Revisited in 2014 during GEUS fieldwork Sulphide Showing

Old and exposed for a long time Exhumation history U/Pb dating on zircons of pegmatites

No major vertical movements since Archean time 2632±7 Ma 2694±4 Ma Miarolitic cavities

Evidence of intrusion at shallow levels (1-2 kb max pressure) 2740 Ma Relics of

5 2694 Ma Pegmatite of the Ruinnæsset intrusions; emplaced at ca <0.

42 Old and exposed for a long time Exhumation history U/Pb dating on zircons of pegmatites with miarolitic cavities provides constraints on the exhumation. No major vertical movements since Archean time 2632±7 Ma 2694±4 Ma Miarolitic cavities in synmagmatic intrusions and pegmatites in Skjoldungen. Evidence of intrusion at shallow levels (1-2 kb max pressure) 2740 Ma Relics of Timmiarmout Orogen 2750 Ma 2700 Ma 2650 Ma 2694 Ma Metasediments Pressure [Gpa] Ma Pegmatite of the Ruinnæsset intrusions; emplaced at ca <0.15 GPa ( 3 km) Depth [km] Ruinnæsset intrusion Ma Granulite facies metamorphism ca 0.8 GPa 2632 Ma Pegmatite Ruinnæsset ca <0.15 GPa ( 3 km) Berger et al. 2014

43 D1 in the Isertoq Terrane What is the nature and timing of the early SE-vergent deformation in the Isortoq Terrane?

Kuummiut Terrane How is the complex evolution of different metamorphic units, i.e. eclogite facies orthogneiss and mafic dykes and amphibolite facies Síportôq Supracrustal Association, in the Kuummiut terrane?

44 Kuummiut Terrane How is the complex evolution of different metamorphic units, i.e. eclogite facies orthogneiss and mafic dykes and amphibolite facies Síportôq Supracrustal Association, in the Kuummiut terrane? What is the nature and timing of the late Niflheim Thrust, one of the youngest structural features in the orogen?

Tasiilaq a region unfolds and new findings

Tasiilaq a region unfolds and new findings Regional overview with emphasize on new understanding and mineral potential Bo M. Stensgaard & Jochen Kolb GEUS & MMR SEGMENT participants Greenland Exploration