Lithogeochemical Sandstone Features of the Pre-Uralian Depression
The article presents information on some lithogeochemical characteristics of sandstones of the Permian system for the Middle and Southern Urals segments of the Pre-Uralian depression. These sandstones are chemically consistent with the typical greywackes or wackes and Fe-sandstones. The diagram SiO2-K2O/Na2O major part of figurative points are concentrated in the range of compositions typical of oceanic island arcs, which is obviously contrary to the real geological situation and due to including the presence of a substantial portion of psammitic carbonate rock fragments and carbonate cement. Comparison of the major rock-forming variation for oxides in sandstones of the Permian system different layers, revealed the existence of multidirectional tendencies and some of the most striking asynchrony of peaks that appear to reflect the specifics of its different sedimentary basins.