Paleoproterozoic volcanic- and limestone-hosted Zn-Pb-Ag-(Cu-Au) massive sulphide deposits and Fe oxide deposits in Bergslagen, Sweden
Field guide (PDF 11.32 Mb)
Summary and aims: The purpose of this field excursion is to discuss the stratigraphy, structure, regional geological setting and origin of volcanic- and limestone-hosted Zn-Pb-Ag-(Cu-Au) massive sulphide deposits in Bergslagen, and their relationships to Fe oxide deposits. The excursion is a collaboration between the IGC and the IGCP-502 project "Global comparisons of volcanic-hosted massive sulphide districts". The excursion will follow and complement the IGCP-502 symposium on "Volcanic-hosted massive sulphide deposits: controls on distribution and timing" at the IGC.
Bergslagen is a mining district in central Sweden that has been a major metal producer for well over 1000 years and which contains over 6000 ore deposits and mineral prospects, including a diverse range of iron oxide and polymetallic sulphide deposits. Bergslagen is the intensely mineralized part of a Paleoproterozoic felsic magmatic province in the Baltic Shield. The supracrustal successions in Bergslagen range from greenschist to amphibolite metamorphic facies and are dominated by moderate to shallow water volcaniclastic deposits that define large felsic caldera volcanoes. Most of the polymetallic sulphide deposits and many of the iron ore deposits are associated with limestones and skarns that occur above or between major caldera eruption cycles. This excursion will demonstrate the latest results and foster debate about whether the sulphide and iron ores are volcanogenic exhalative, volcanogenic replacement, synvolcanic intrusion-related, or syn-metamorphic in origin. The excursion will visit the Garpenberg and Sala limestone-, skarn- and volcanic-hosted stratabound Zn-Pb-Ag-(Cu-Au) sulphide deposits, the Zinkgruvan volcanic-hosted stratiform Zn-Pb-Ag-(Cu-Au) deposit, the Viker-Älvlången limestone-hosted stratiform Zn-Fe-Mn mineralization, the Dannemora limestone-hosted manganiferous magnetite-skarn deposit and the Stollberg limestone-hosted manganiferous magnetite- and Zn-Pb-Ag-skarn deposits. Outcrops of greenschist to amphibolite facies volcanic rocks, stromatolitic limestones and skarns that host the ore deposits will also be studied.
Leaders: Rodney Allen (Boliden Mineral and Luleå University of Technology; Rodney.Allen(at)ltu.se); Magnus Ripa (Geological Survey of Sweden; magnus.ripa(at)sgu.se); Nils Jansson (Luleå University of Technology; niljan(at)ltu.se)