Abstract

Copper, zinc, and uranium showings at Pahtavuoma in the western part of the Kittilae greenstone complex, northern Finland, are associated with volcanogenic sedimentary schists sandwiched between lava beds.Lithogeochemical studies demonstrate that the copper showings are surrounded by halos of Ag, Co, and As and that no significant correlation exists between Cu and Zn in the deposits. The delta 34 S values for the sulfide sulfur fall into two groups: the copper ore proper, with negative values up to --15.5 per mil, and the low-grade occurrences in the hanging wall, with positive values up to +31.2 per mil.The mineralization process was related to eruptions of volcanics into the sedimentation basin. The sulfur in the sulfide deposits derived from marine and volcanogenic sources. The primary stratabound and low-grade orebodies were deformed by tectonic movements succeeding the main folding stage at the same time as sulfides were remobilized into breccias.Ore showings similar to those in the Kittilae greenstone complex are encountered in some other Precambrian greenstone belts in Scandinavia, e.g., at Viscaria and Kopparaasen in northern Sweden and at Bidjovagge in northern Norway.

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