HIGH-Mg RAW MATERIALS: MINERAL PRODUCTS OF THE KARELIAN-KOLA REGION, RUSSIA.

Geodynamic regimes at an early stage in the formation of the earth crust are essential for the formation of high-Mg rocks. The komatiite-basalt series of Archean greenstone belts (high-Mg volcanics) and boninite-like assemblages in the supracrustal units of the same belts, with which talc, magnesite and serpentine of two stages (Meso- and Neoarchean), newly-formed after high-Mg rocks, are associated, are the earliest units productive for industrial minerals. Siliceous high-Mg series represented by formed large lava flows with gabbronorite dyke swarms and the formation of layered mafic-ultramafic intrusives. Large magnetite units were formed in serpentine ultra-alkaline rock which has suffered hydrothermal leaching of magnesium from serpentinite. A third class of high-Mg rocks in this region is associated with the dolomites of the Paleoproterozoic sedimentary-volcanic units of the Karelian-Kola region. The Kola Peninsula has many high-Mg-silicate rock deposits that meet the requirements for the production of refractory, building and technical materials on their basis such as Kovdor and Khabozero olivinites, Sopcheozero and Pados-tundra dunites, etc. Sungulitic and iddingsitic concentrates are suitable for the production of the pigments and fillers of varnishes, paints and polymeric materials, technical rubber and high-Mg meliorants. Karelia has two types of talc-bearing rocks. Deposits and occurrences of type I (apoultramafic type) are common in ultramafic rocks of peridotite-picrite or dunite-peridotite composition. Occurrences of type II (apocarbonate type) are confined solely to the dolomites of the Jatulian superhorizon of the Proterozoic. Low-iron talc to talcite occurrences are associated with these complexes. The Karelia-Kola region, located on the Fennoscandian Shield, is promising for high- Mg raw materials. [ABSTRACT FROM AUTHOR]