Geneza mineralizacji uranowej w dolnopermskich łupkach walchiowych (depresja śródsudecka) na tle wykształceni a litofacjalnego
Abstract
GENESIS OF URANIUM MINERALIZATION IN THE LOWER PERMIAN WALCHIA SHALES (INTRA - SUDETIC TROUGH, SW POLAND) AND ITS FACIES CONTEXT
Summary
Lithofacies characteristic of the Lower Permian Walchia Shales from the Intra - Sudetic Depression was presented here. Several lithofacies were disinguished: calcareous black shales (A), black and dark-grey clayley and silty shales (B), grey sandy siltstones and fine sandstones (C), red mudstones and fine sandstones with intensive (D1) or weak (Dz) bioturbation, and conglomerates (E). Volcanic rocks of effusive complex such as andesites and ryolitic tuffs occurred within described deposits. Clastic deposits were accumulated within various zones of the lake, from well oxidized littoral zone up to highly reduced pelagic one. Deposits of alluvial fans had a local importance. Uranium mineralization, syngenetic or early diagenetic in origin, was connected mainly with lithofacies A. Also some subtle signs of epigenetic mineralization were found. Possible source of uranium for mineralized horizons of the Walchia Shales was - according to author – the Lower Permian volcanism, Variscan granitoids of the Karkonosze Mts and the Lower Carboniferous volcanic rocks. The Lower Permian volcanism, synchronous with uranium-bearing deposits, could be regarded as significant catalyzer of uranium solution processes from alimentary areas. Alcaline solutions, generated during tuff weathering, enlarged considerably the chemical activity of ground waters, infiltrating rocks in alimentary areas.
Summary
Lithofacies characteristic of the Lower Permian Walchia Shales from the Intra - Sudetic Depression was presented here. Several lithofacies were disinguished: calcareous black shales (A), black and dark-grey clayley and silty shales (B), grey sandy siltstones and fine sandstones (C), red mudstones and fine sandstones with intensive (D1) or weak (Dz) bioturbation, and conglomerates (E). Volcanic rocks of effusive complex such as andesites and ryolitic tuffs occurred within described deposits. Clastic deposits were accumulated within various zones of the lake, from well oxidized littoral zone up to highly reduced pelagic one. Deposits of alluvial fans had a local importance. Uranium mineralization, syngenetic or early diagenetic in origin, was connected mainly with lithofacies A. Also some subtle signs of epigenetic mineralization were found. Possible source of uranium for mineralized horizons of the Walchia Shales was - according to author – the Lower Permian volcanism, Variscan granitoids of the Karkonosze Mts and the Lower Carboniferous volcanic rocks. The Lower Permian volcanism, synchronous with uranium-bearing deposits, could be regarded as significant catalyzer of uranium solution processes from alimentary areas. Alcaline solutions, generated during tuff weathering, enlarged considerably the chemical activity of ground waters, infiltrating rocks in alimentary areas.