Geodynamic settings for Paleoproterozoic gold mineralization in the Svecofennian domain: A tectonic model for the F?boliden orogenic gold deposit, northern Sweden

详细信息    查看全文

• 作者：Glenn Bark ; P?r Weihed
• 关键词：Fä ; boliden ; Fennoscandian Shield ; Svecofennian orogen ; Orogenic gold ; Structural model ; Ore shoot
• 刊名：Ore Geology Reviews
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：48
• 期：Complete
• 页码：403-412
• 全文大小：2382 K

文摘

Northern Sweden is currently experiencing active exploration within a new gold ore province, the so called Gold Line, situated southwest of the well-known Skellefte VMS District. The largest known deposit in the Gold Line is the hypozonal F?boliden orogenic gold deposit. Mineralization at F?boliden is hosted by arsenopyrite-rich quartz veins, in a reverse, mainly dip-slip, high-angle shear zone, in amphibolite facies supracrustal host rocks. The timing of mineralization is estimated, from field relationships, at ca. 1.8 Ga.

The gold mineralization is hosted by two sets of mineralized quartz veins, one steep fault-fill vein set and one relatively flat-lying extensional vein set. Ore shoots occur at the intersections between the two vein sets, and both sets could have been generated from the same stress field, during the late stages of the Svecofennian orogen.

The tectonic evolution during the 1.9-1.8 Ga Svecofennian orogen is complex, as features typical of both internal and external orogens are indicated. The similarity in geodynamic setting between the contemporary Svecofennian and Trans-Hudson orogens indicates a potential for world-class orogenic gold provinces also in the Svecofennian domain.

The Swedish deposits discussed in this paper are all structurally associated with roughly N-S striking shear zones that were active at around 1.8 Ga, when gold-bearing fluids infiltrated structures related to conditions of E-W shortening.