Orogenic gold provinces in the Svecofennian domain occur in three arc complexes: in the 1.93-1.87 Ga primitive arc complex along the collision zone (e.g. Savo belt in the Raahe-Ladoga zone) between the Svecofennian and Karealian domains (Laivakangas province), in the 1.90-1.87 Ga Central Svecofennian accretionary arc complex (Seinäjoki, Tampere and Pirkkala provinces) and in the 1.90-1.82 Ga Southern Svecofennian accretionary arc complex (Häme and Rantasalmi provinces). In the Laivakangas province, the medium-T amphibolite facies to granulite facies peak metamoprhism took place at around 1.885 Ga. In the Central Svecofennian arc complex, the low-P greenshist to amphibolite facies peak metamoprhism in the Tampere province, as well as the high-T amphibolite facies peak metamorphism in the Pirkkala province took place at 1.88 Ga. In the Southern Svecofennian arc complex, the age of the predominantly amphibolite facies peak metamoprhism is between 1.88 and 1.86 Ga. This latter complex also suffered a high temperature thermal event at 1.83-1.81 Ga.

Tectonic setting and timing of Svecofennian orogenic gold deposits in Finland

(Last update: 20.05.2020)

Svecofennian orogenic gold provinces

Age of orogenic gold mineralization in the Svecofennian domain is proorly known. Cross-cutting realtionships with dated hos rocks, as well as structural and paleomagnetic evidences suggest that formation most of gold deposits post-dated early deformation.  However, some deposits also show recrystallization indicating that the orogenic gold metallogeny may also be diachronous in the Svecofennian domain.

At Jokisivu (Pirkkala province), U-Pb ages from zircon overgrowths and titanite in altered host rocks suggest to 1.81-1.80 Ga age of hydrothermal events leading to the deposition of gold. The mineralization is controlled by second and third order structures along the major NW-SE and SW-NE trending shear zones. Simlar structural setting and orientation also characterize most of the orogenic gold systems in other provinces of the Svecofennian domain. In the Uusima province, the age of gold mineralization along similar structures is estimated to be between 1.82 and 1.79 Ga.