Naurispuro - Gold Database

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Name	Naurispuro	DATA UPDATED	24.5.2007
Alternative names	Korkea-Aho
Deposit summary	NAURISPURO, in the Kuhmo greenstone belt, is an Archaean orogenic gold occurrence with no resource estimate available. It comprises a set of N-trending subvertical lodes which may be subsidiary to the main shear zone of the Kuhmo greenstone belt. No information available on host rock or siting of gold.
LOCATION
Geological domain	Archaean	Belt	Kuhmo
Site photo		Regional map
Map sheet	441211
Northing (kkj)	7147750	Easting (kkj)	4453750
Latitude	64.42536N	Longitude	29.03679E
Municipality	Kuhmo
Nearest town, roads	39 km NW from Kuhmo. A sealed road across the area, five km from railway.
MINING
Exploration licence no	6503/1, 6503/2, 7457/4	Mining concession no
Present holder	Kuhmo Metals Oy (2006–)
Previous holders	Geological Survey of Finland (GTK), Outokumpu Mining Oy (2003), Polar Mining (2003–2006)
Mine photo 1		Mine photo 2
Mine photo 3		Mine photo 4
Status of development	Prospect
When mined
Resources
Deposit size (Mt)		Reference (size)
Total in-situ gold (kg)		Reference (in-situ Au)
Total gold production (kg)		Reference (gold prod)
Production of other metals
Extent of mineralisation
Lodes	Subvertical lode(s) [1].
Best sections
EXPLORATION
Discovery year	1997
Discovery	By GTK: regional Au and As anomalies in till were the first indication; occurrence was discovered by drilling into a combined local Au-As-Te anomaly in till-bedrock interface and ground geophysical anomaly [2].
Exploration history	GTK (1997–1999) [1,2]: Regional and local till geochemical surveys, ground magnetic and slingram survey, bedrock mapping, diamond drilling.
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
Drilling	GTK (1997): Five diamond-drill holes, total 355.5 m [2].
Elements analysed	By ICP-AES: Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, P, Sc, Sr, Ti, V, Y and Zn; by GAAS: Au and Te [2].
Primary dispersion
Secondary dispersion	Au and As anomaly in till [2].
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: Tapio Halkoaho
ORE
Siting of gold
Fineness
Major opaques
Minor opaques
Gangue
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	Located in the central part of the Late-Archaean Kuhmo Greenstone Belt, in aN-trending, subvertical sequence dominated by mafic tholeiitic metavolcanic rocks with thin ultramafic (komatiitic?) interlayers [1,2].
Major host rocks
Minor host rocks
Intrusives	NW-trending Palaeoproterozoic dolerite cut arcoss the deformed Archaean rocks in the rergion [1].
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	Upper-greenschist facies [1].
Metamorphic mineral assemblage
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style	Ductile(?) [2]
Closest major shear	The N-trending main shear zone of the Kuhmo greenstone belt [1].
Controlling structure	Probably similar or the same structures as at Timola, 1 km to the north: a set of N-S trending narrow shear zones which are late-D3 or D4 structures [2].
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 [3,4]. D2: 2850-2837 Ma, D3: 2701-2697 Ma, D4: peaked at 2657±32 Ma [4]. Age of D2 is probably 2820±15 Ma [1] or 2843±18 Ma [5].
Ore fabric
Veins
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 3
ALTERATION
General alteration
Proximal alteration
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
TIMING	During ca. 2720–2650 Ma [1].
GENETIC MODEL
GENETIC TYPE	Orogenic	References	[1]
Alternative genetic type 1		References
Alternative genetic type 2		References
References 1. 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 1992–2 001 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) 2. Halkoaho, T., Niskanen, M. & Tenhola, M. 2001. Turkimustyöselostus Kuhmon kaupungissa valtausalueilla Naurispuro 1 ja 2 (kaivosrekisterinumerot 6503/1 ja 6503/2) suoritetuista kulta- ja nikkelimalmitutkimuksista vuosina 1997–1999. English summary: A research report of gold and nickel exploration concerning the claims of Naurispuro 1 and 2 (Mine Register nos. 6503/1 and 6503/2) in Kuhmo, during 1997–1999. Geol. Surv. Finland, Report M06/4412/2001/4/10. 8 p. (1.8 MB) 3. 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. 4. Luukkonen, E. 2001. Lentiiran kartta-alueen kallioperä. Summary: Pre-Quaternary rock of the Lentiira map-sheet area. Suomen geologinen kartta 1:100 000. Kallioperäkarttojen selitykset, 4414 + 4432 Lentiira. 68 p. 5. 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.
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