Ultramafic Varėna suite in the Precambrian crystalline basement of the Southern Lithuania - Implications for the origin

Abstract

The Varėna Suite comprises a set of ultramafic rocks: olivinic, pyroxenic, magnetitic, dolomitic, and apatite bearing rocks, which form complex bodies of few sq. km in the Precambrian crystalline basement near the Varėna town in Southern Lithuania. Occurrences of few mineral commodities are related to the Varėna Suite. Magnetitic rocks contain essential resources of high grade iron ores. Phlogopite, apatite, REE and Thmineralization is related to the Varėna Suite. The assessment of the potential for these commodities is primarily dependent on the origin of Varėna Suite, which is still disputed. The models of metasomatic (skarn), and igneous (layered intrusion) origin are proposed earlier. The article presents an overview and reinterpretation of the recent data on the Varėna Suite, its petrographic and geochemical characteristic, as well as the arguments for igneous origin of the Varėna Suite, as the polyphase intrusion with subsequent metasomatic alteration, with alkaline trend.