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BACHELOR THESIS: 3D modelling of hydrothermal altera>on and Au mineralisa>on in the Nuuluk area
Tartoq gold province (SW Greenland)
Sara E. Hoffritz Done in co-‐opera>on with University of Copenhagen and Geological Survey of Denmark and Greenland
Nuuluk
Figur Map showing location of Nuuluk in SW Greenland and the regional geology. Map is modified after GEUS (figure: Henriksen 1968, Escher og Jensen 1974, Jensen 1975)
Figur Map of the loca>on of different drill cores (red dots), both diamond drilling in the west and winkie drillings in the east along with surface samples shown by their gold value (Figur: King,1985)
Background
• More than 40 years of explora>on • Two parallel altera>on zones of old meta-‐volcanics in a classic greenstone belt which has been hydrothermally altered by carboniferous fluids
• Rock types are schist and hydrothermal altered meta-‐volcanics
• 12.30 ppm in the Eastern zone
• 6.63 ppm in the Western zone
METHODE
Cross sec>ons
DH5 125m
surfaceAu (78 ppb, projected)
Au (132 ppb, projected)
Au (730 ppb/2m)Au (217 ppb/2m)
West East
Pro!le A
DH1 134 m
DH2109 m
Au (6.65 ppm/2m)
Au (86 ppb/4m)Au (516 ppb/2m)
Au (61 ppb) Au (887 ppb)
DH3
DH4
surface
Au (127 ppb/4m)
Au (68 ppb/4m)
97 m
109 m
West East
DH1 & DH2 DH3 & DH4
DH5
Geochemical features Profile log and sample analysis
Imported data
From reports from Nunaoil, Greenex and GEUS
• Drill hole data – Loca>on, depth, azimuth and dip – Lithology – Measurements of Au, As and Cu
– Structural measurements
• Surface samples -‐> topography
Lithology
Lithology
Lithology -‐ Structures
Gold occurrences
Western upper zone
Eastern, northern zone
Western lower zone Eastern, southern zone
HALOES: Red: 95< ppb (!) Orange: 80-95 ppb Yellow: 60-80 ppb Bright: 50-60 ppb
Lithology + Gold occurences
Results • Modelling of gold volumes are possible in spite of low values and gives a good idea over the poten>al in the area
• The gold is in boundary zones with lower stability – but in different rock types – structures ?
• There are at least four mineraliza>on zones • Gold correlates with As and Cu • There is a connec>on with high gold values and the graphite-‐ and magne>te schist
• Old and new data can give a 3D view of the geometry of the gold occurrences
• More data is needed • GEUS: Project re-‐opened and area will be more inves>gated next field season