Syrjälä - Gold Database

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Name	Syrjälä	DATA UPDATED	29.8.2007
Alternative names	Kuohusuo, Syrjä
Deposit summary	SYRJÄLÄ, in the Suomussalmi greenstone belt, has an in situ resource estimate of 160 kg gold (no JORC-compliant resource calculation is available). It is an Archaean orogenic gold deposit comprising three parallel, narrow lodes in intermediate volcaniclastic rock in a NW-trending, ductile shear zone in an overturned anticline. Alteration mineral assemblages indicate mineralisation under amphibolite-facies conditions. Free native gold(?).
LOCATION
Geological domain	Archaean	Belt	Suomussalmi
Site photo		Regional map
Map sheet	451110
Northing (kkj)	7227500	Easting (kkj)	4455500
Latitude	65.14081N	Longitude	29.04823E
Municipality	Suomussalmi
Nearest town, roads	27 km N from Suomussalmi. 5 km from the sealed highway no. 5, a gravel road to the area. 40 km to railway line.
MINING
Exploration licence no	6318/1–2, 6748/1–4, 7270/1–2	Mining concession no
Present holder	OPEN FOR ACQUISITION
Previous holders	Geological Survey of Finland (GTK) (1996–2001), Outokumpu Oyj (2001–2003), Polar Mining (2003–2006)
Infra fig 1		Infra fig 2
Claim fig 1		Claim fig 2
Mine photo 1		Mine photo 2
Mine photo 3		Mine photo 4
Status of development	Prospect
When mined
Resources	0.057 Mt @ 1.55 ppm Au + 0.09 Mt @ 1.15 ppm [5].
Deposit size (Mt)	0.066	Reference (size)	[5]
Total in-situ gold (kg)	161	Reference (in-situ Au)	[5]
Total gold production (kg)		Reference (gold prod)
Production of other metals
Extent of mineralisation	A few metres to 15–20 m wide, open at depth of 100 m [1].
Lodes	Three lodes, one at Syrjälä N and two at Syrjälä S, dipping at 50–65° [1,5]. The S lode is in a contact zone between mafic and intermediate volcanic rocks [8]. The N lode is 1–4 m thick, is open at 70 m depth [8].
Best sections	Syrjälä S: 1 m @ 85.7 ppm, 1 m @ 12.7 ppm, 1 m @ 3.9 ppm Au [5,8]. Syrjälä N: 0.2 m @ 57 ppm, 1 m @ 5.2 ppm, 1 m @ 2.9 ppm, 1 m @ 2.5 ppm Au [8].
EXPLORATION
Discovery year	1995
Discovery	By GTK: first indications were a regional Au anomaly in till and an auriferous sample from a glacial erratic boulder, provided by an amateur prospector; further indications were the high Au, As and Te concentrations detected by percussion drilling into till-bedrock interface; the deposit was detected by drilling by GTK [1,5,6].
Exploration history	GTK (1995–) [1,5,6,8]: Bedrock mapping, till geochemical survey, percussion drilling into till-bedrock interface, diamond drilling, low-altitude airborne magnetic, electromagnetic and radiometric survey, magnetic, slingram and IP ground survey.
Section figure 1		Plan figure 1
Section figure 2		Plan figure 2
Section figure 3		Plan figure 3
Trench fig 1		Trench fig 4
Trench fig 2		Trench fig 5
Trench fig 3		Trench fig 6
Explor site photo 1		Explor site photo 2
Geophysical response	IP indicated the pyrite-rich horizons and ground-magnetic survey possible shear or fault zones; no specific response by slingram [5].
Drilling	GTK (1996–1999): 41 diamond-drill holes, total 3133 m [4,5].
Elements analysed	All samples by ICP-AES for As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, S, Sb, Sr, Ti, V and Zn; in addition Ag, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn by AAS, Au and Te by GFAAS, and Al, As, Ba, Bi, Ca, Ce, Cl, Cr, Cu, Fe, Ga, K, La, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Sb, Sc, Si, Sn, Sr, Th, Ti, U, V, Y, Zn, Zr by XRF [5,6].
Primary dispersion
Secondary dispersion	Extensive Au-Te anomaly in till [8].
Primary anomaly fig 1		Secondary anomaly fig 1
Primary anomaly fig 2		Secondary anomaly fig 2
Primary anomaly fig 3		Secondary anomaly fig 3
Primary anomaly fig 4		Secondary anomaly fig 4
Primary anomaly fig 5		Secondary anomaly fig 5
Economic evaluations
Exploration geologist in charge	GTK: Erkki Luukkonen, Kimmo Pietikäinen.
ORE
Siting of gold
Fineness
Major opaques	Pyrrhotite, pyrite, arsenopyrite [5].
Minor opaques	Native gold [5].
Gangue	Quartz, sericite, biotite, tourmaline, scheelite [5].
Ore miner. photo 1		Ore miner. photo 5
Ore miner. photo 2		Ore miner. photo 6
Ore miner. photo 3		Ore outcrop photo 1
Ore miner. photo 4		Ore outcrop photo 2
Ore composition
Enriched elements
Ore fluid
Stable isotopes
Pb isotope data
GEOLOGY
Geological setting	The mineralisation is in the southern part of the late Archaean Suomussalmi greenstone belt and is in the rocks of the 2.8–2.7 Ga(?) Saarikylä Group of the greenstone belt [1]. It is in a sequence dominated by mafic and intermediate metavolcanic rocks, dipping at 65°, with minor metakomatiitic units, in a contact zone between mafic and intermediate to felsic units, in an overturned antiform [5].
Major host rock	Intermediate volcaniclastic rock [5].
Minor host rock	Mafic, felsic and intermediate metavolcanic rocks, uralite porphyrite [5].
Intrusives	[1,2,3]: TTG granitoids, from 2739±8 Ma to 2697±10 Ma of age, are abundant within and near the greenstone belt. The alteration halo is cut by an unaltered dolerite dike, which resembles dykes of a Proterozoic dyke swarm cutting the greenstones of the Suomussalmi Greenstone Belt [5]. In the Kiannanniemi area, there apparently are Palaeoproterozoic dolerite dykes of three ages, all clearly postdating gold mineralisation [8].
Regional geol map 1		Outcrop photo 1
Regional geol map 2		Outcrop photo 2
Local geology map 1		Outcrop photo 3
Local geology map 2
METAMORPHISM
Metamorphic history
Metamorphic grade
Metamorphic mineral assemblage
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style	Dominantly ductile [5].
Closest major shear
Controlling structure	NW-trending shear zones which follow the axial plane foliation, in Syrjälä S along sthe strike of bedding [1,5].
Deformation history	At least, six deformation stages during the late Archaean and two deformation stages during the Palaeoproterozoic detected in the area; gold mineralisation is related to the Archaean late D3 and/or D4 stages [2]. NW- and SW-trending shear zones and joints cut the axial plane foliation and the mineralized zones - these may be associated with emplacement of Proterozoic dolerite dikes [5]. Age of D2 is probably 2820±15 Ma [8] or 2843±18 Ma [9]. Syn-D3 granodiorite suggests an age of ca. 2718 Ma for the D3 stage [8].
Ore fabric	Mylonitic [5].
Veins	Auriferous, deformed, quartz carbonate veins and barren, almost undeformed, quartz veins [8].
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 2
Structure photo 3		Vein photo 3
ALTERATION
General alteration	Biotitisation of hornblende, sericitisation of plagioclase [5]. Alteration halo extends for 0–70 m laterally away from ore-grade rock [8].
Proximal alteration	Quartz-biotite-sericite [5].
Intermediate alteration
Distal alteration
Zonation figure		Prox alteration photo 1
Alteration photo 1		Prox alteration photo 2
Alteration photo 2		Intermed alteration photo
Alteration photo 3		Distal alteration photo 1
Post-mineralisation modifications	Formation of NW- and SW-trending shear zones, possibly during the Proterozoic [5].
TIMING	Late Archaean [2].
GENETIC MODEL	Orogenic "mesothermal" deposit with a distinct structural control and having formed under amphibolite-facies conditions, formed during late-Archaean cratonisation [7].
GENETIC TYPE	Orogenic	References	[7]
Alternative genetic type 1		References
Alternative genetic type 2		References
References 1. Pietikäinen, K. 1998. Personal communication 14/9/98. 2. Luukkonen, E., Pajunen, M. & Poutiainen, M. 1992. Kuhmo-Suomussalmen alueen arkeeisen kallioperän rakenne-evoluutio ja Au-aiheet. In: E. Ekdahl (ed.) Suomen kallioperän kehitys ja raaka-ainevarat. Vuorimiesyhdistys, Sarja B, 51, 11–12. 3. Luukkonen, E. 1992. Late Archaean and Early Proterozoic structural evolution in the Kuhmo-Suomussalmi Terrain, eastern Finland. Annales universitatis Turkuensis. Ser. A. II 78, 1–37. 4. Sorjonen-Ward, P., Nironen, M. & Luukkonen, E. 1997. Greenstone associations in Finland. In: M. J. de Wit and L. D.Ashwal (eds) Greenstone Belts. Clarendon Press, Oxford. 677–698. 5. Pietikäinen, K., Hartikainen, A., Niskanen, M. & Tenhola, M. 2001. The gold prospects; Kuikka, Syrjälä N, Syrjälä S and Tupakkiloma in Kiannanniemi, Suomussalmi, Eastern Finland. www.gtk.fi/explor/tender/Kuikka/kuikka.htm 6. Heino, T. 2000. Mineral Resource Assessment of the Kuikkapuro 1 (mine reg. no. 6748/1), Kuikkapuro 2 (no. 6841/1), Kuikkapuro 3 (no. 6880/1), Kuikkapuro 4 (no. 6880/2) and Kuikkapuro 5 (no. 6912/1) gold mineralizations. Associated with the Geol. Surv. Finland, Report CM06/4511/2000/1. 7. Papunen, H., Halkoaho, T., Liimatainen, J. & Luukkonen, E. 2001. Metallogeny of the Archaean Tipasjärvi-Kuhmo-Suomussalmi greenstone belt, Finland. AGSO – Geoscience Australia, Record 2001/37, 456–458. 8. Luukkonen, E., Halkoaho, T., Hartikainen, A., Heino, T., Niskanen, M., Pietikäinen, K. & Tenhola, M. 2002. Itä-Suomen arkeeiset alueet -hankkeen (12201 ja 210 5000) toiminta vuosina 1992?2001 Suomussalmen, Hyrynsalmen, Kuhmon, Nurmeksen, Rautavaaran, Valtimon, Lieksan, Ilomantsin, Kiihtelysvaaran, Enon, Kontiolahden, Tohmajärven ja Tuupovaaran alueella. Geol. Surv. Finland, Report M19/4513/2002/1. 265 p. (in Finnish, 130 MB) 9. Sorjonen-Ward, P. & Luukkonen, E.J. 2005. Archean rocks. In: Precambrian Geology of Finland – Key to the Evolution of The Fennoscandian Shield. Elsevier Science B.V., Amsterdam, 19–9 9. 10. Goode, K. 2004. Dragon Mining NL (DRA) – Bringing Scandinavian Gold Mines into Production. 12 p. (938 KB)
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