A. A. Petrova, E. N. Afanaseva

Gold-uranium mineralization of the Early Proterozoic Lekhta Structure (East Karelia)

Abstract. "The paper reviews geological aspects of the Lekhta Structure (East Karelia) and characterizes the gold-uranium mineralization objects localized within the Sariolian conglomerates of the Zheleznye Vorota Formation (Zheleznye Vorota, Nigalma, Kala-Lampi, Lobash-Ruchey, and Varozero) and the Jatulian conglomerates and gritstones (Rigovaraka, Borovaraka, and Kichu-Lampi). Both gold and uranium mineralization were concluded to be formed within single ore-forming systems. The paper outlines the gold-uranium mineralization prerequisites and features (structural, lithological, hydrothermal-metasomatic, and geochemical), which can be considered as elements of geological exploration models used to identify gold ore objects in other Early Proterozoic structures of the Karelian–Kola region. The gold-uranium mineralization referred to the “gold-bearing conglomerate” formation was likely to be developed under Svecofennian tectonic-magmatic activation conditions which resulted in remobilizing, redepositing, and centralizing primary gold within strata prospective for gold and uranium. The author gives recommendations for further study of the Lekhta Structure gold potential, including those for identifying the zones of tectonic and hydrothermal-metasomatic alterations that control the gold-uranium object distribution, as well as for clarifying relationship between and sequence of gold and uranium mineralization."

Keywords: the Baltic Shield, gold-bearing conglomerates, prerequisites, gold-uranium mineralization features, geological exploration models