Vanadium - Regional Geological Setting
Finland is located in the middle of the Fennoscandian Shield, which is the largest exposed area of Precambrian rocks in Europe and is geologically similar to other shield areas hosting world-class mining camps especially in Canada and Western Australia.
The Early-Proterozoic layered intrusions located in northern Finland and in north-western Russia constitute a significant chromium, platinum group element, vanadium and nickel province also in global scale. The only known layered intrusions in Western Europe with any significant potential for these commodities are located in Finland. These fertile intrusions can be divided into two age groups, the 2,440 Ma and the 2,050 Ma layered intrusions, which host slightly different type of mineralisation.
Layered intrusions are emplaced through the cratonised Archaean basement and possibly earliest Proterozoic supracrustal rocks between the Archaean basement complex and the overlying (younger) Proterozoic supracrustal sequence emplaced in sheet or sill like chambers. Soon after their emplacement, intrusions were broken by vertical movements and split into a number of structural blocks. The consequent uplift and erosion period removed upper parts of most intrusions blocks and their original roof rocks and in some blocks erosion went so far that only lowest stratigraphical levels ('roots') have preserved. At same time the 2,050 Ma layered intrusions located in northern and eastern Finland were emplaced through the locally rifted Archaean crust. The tilting of intrusions and their roof and footwall units in their present attitude took place in the Sveco-Karelian orogeny roughly 1900-1800 Ma ago.
Vanadium mineralisation is typically associated with magnetite gabbros representing the upper stratigraphic units of layered intrusions. In the Porttivaara block of the Koillismaa layered igneous complex the magnetite gabbro layer was mined as vanadium ore by Rautaruukki Oy in 1970's and 1980’s. Other significant vanadium bearing magnetite gabbro horizons are related to Syöte, Koitelainen and Akanvaara intrusions as well as to the Monchegorsk and Imandra intrusions in north-west Russia. Vulcan has acquired a significant land holding on the vanadium resources related to Porttivaara, Syöte, Koitelainen and Akanvaara layered intrusions.
Location of Vulcan’s vanadium projects and Finnish steel mills