A gold-bearing volcanogenic-exhalative horizon in the

• Main Authors: Adam A. Garde, Bjørn Thomassen, Tapani Tukiainen, Agnete Steenfelt
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Archaean; gold; Nuussuaq; supracrustal rocks; West Greenland; Greenland; Saqqaq
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.523.4745; http://www.geus.dk/publications/bull-gl/nr181/nr181_p119-128.pdf

host stratiform gold mineralisation in a 3–4 m thick impure chert horizon of volcanogenic-exhalative origin; chip samples average c. 0.8 ppm Au (thickness 3.3 m) over a strike length of 8 km, including 1.1 ppm Au (thickness 3.7 m) over a strike length of 1.6 km. Silicate minerals in and adjacent to the mineralised horizon include chrome-bearing tourmaline, staurolite, fuchsite, and manganiferous garnet. The Saqqaq supracrustal rocks form an almost 30 km long, NW-striking and SW-dipping sequence, which is presumed to be of Archaean age and consists of amphibolite facies mafi c and ultramafi c metavolcanic rocks, associated minor volcanogenic-exhalative horizons, and quartzo-feldspathic metasediments. The sequence is surrounded by Archaean(?) orthogneisses and intruded by an up to c. 100 m thick trondhjemitic sill, and appears to outline a large asym-metric, isoclinal fold (possibly of Archaean age) which was refolded in the lower Proterozoic.