Gold Exploration in the Early Proterozoic Ketilidian Orogen, South Greenlan

Exploration & Mining Geology, Vol. 4, No. 3, 1995

H. STENDAL, Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K., Denmark. L. GRAHL-MADSEN and H.K. OLSEN, Nunaoil A/S, Box 790, DK-3900 NUUK, Greenland. H.K. SCHØNWANDT and B. THOMASSEN, The Geological Survey of Greenland (GGU), Øster Voldgade 10, DK-1350 Copenhagen K., Denmark

The central part of the early Proterozoic Ketilidian orogen in South Greenland consists of an I-type granitoid batholith transected by four regional NE-SW-trending shear zones. The batholith was probably emplaced during subduction, from the south toward the Archaean craton in the north, in a sinistral transpressional system. A regional sediment sampling program covering 5000 km2 shows a close connection between a gold-mineralized trend and one of the major shear zones within the epizonal facies of the batholith. The gold mineralization is not directly related to the major shear zones, but occurs in quartz-veined and silici?ed second-order structures. High-grade (up to 114 ppm Au over 6 m) low-tonnage mineralization is found within these second-order structures cutting both amphibolites and granitoids. The mineralization is characterized by negligible or small alteration halos. Gold is associated with various element combinations of enhanced As-Bi-WCu, which indicate that the mineralization is mesothermal in origin.

Keywords: Exploration, Gold exploration, Proterozoic, Greenland, Batholith, Sampling.