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Silurian key succession of the western Subpolar Urals is exposed on the Kozhym River, in the section 236. In this paper, lithology of carbonate rocks of the Sizim Stage (Ludlow) exposed in that section is discussed. It is demonstrated that in formation of limestones and dolostones significant role was played by various benthic organisms, including cyanobacteria — the main builders of stromatolites which existed in extremely shallow-water conditions.

Keywords: Sizim stage, Ludlow, Silur, stromatolites.

DOI: 10.19110/2221-1381-2016-8-3-8

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For the first time we studied the conditions of formation of gold-telluride-palladium mineralization in Krutoy deposit. It is confined to the central part of khengursky basalt complex. This deposit is represented by a NW elongated gabbro-dolerite body located in Middle Ordovician argillaceous shales. The gold-telluride-palladium mineralization is mainly associated with quartz-chalcopyrite veins. The mineral-forming fluid is characterized by a very low gas saturation. According to the composition of the gas phase the inclusions are divided into nitrogen-methane and carbon dioxide-nitrogen. The mineral-formation fluids are dominated by magnesium and calcium salts. We determined that the formation temperature of the vein quartz was close to 300—490 °C. The sulfide and associated gold-telluride mineralization was formed at lower temperatures, less than 260 °C.

Keywords: gold-telluride-palladium mineralization, fluid inclusions, gabbro-dolerite, gas chromatography, Raman spectroscopy.

DOI: 10.19110/2221-1381-2016-8-9-13

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Dedicated to V.N. Okhotnikov and L.V. Makhlaev — known
researchers of geology of Russian polar areas

The paper presents new data on the petrography and geochemistry of granitic bodies from the north-eastern part of Gerdizsky massif. The genesis of gneissic structure of granites from this massif is still controversial. Researchers assume autochthonous origin by granitisation processes, and others — intrusive genesis. The study of the granite body of north-eastern part of Gerdizsky massif revealed that granites, interpreted as ultrametamorphogenous autochthonous formations, are intrusive A-granites and the characteristic gneissic structure of rocks is formed by tectonic effects.

Keywords: A-granites, cataclastic structure, Gerdizsky massif, Polar Urals.

DOI: 10.19110/2221-1381-2016-8-14-20

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Possibility of taxonomic diagnostics of the juvenile Pa-elements of the advanced Siphonodella is considered. The set of the observable taxonomic features varies significantly in dependence of the ontogeny stage. The adult Pa-elements demonstrate full association of morphological features, but the juvenile forms can be distinguished just on the basis of carina curvature, platform outline and ornamentation, the rostrum morphology, and the element symmetry. Some species share these features and are indistinguishable at the early stages of ontogeny. Siphonodella crenulata, S. duplicata, S. quasinuda, S. semichatovae M2, S. lobata are recognizable at the earliest ontogenetic stage. The group having numerous long ridges can be differentiated at the species level just since the second stage of ontogeny (elements composed by more than 4 lamella sets). Siphonodells with more than two short ridges and S. hassi can be determined since the second stage ontogeny too.

Keywords: conodonts, Siphonodella, ontogeny, juvenile forms, Early Carboniferous, Tournaisian.

DOI: 10.19110/2221-1381-2016-8-21-26

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The amino acid composition of organic matter of the domanik shales from a section of rivers Chut and Sharyu was studied. It was established that aliphatic amino acids prevailed in group composition of the amino acids that was typical for algal organic matter. It was shown that amino acids distribution in domanik samples depended on organic matter catagenesis and mineral composition of rocks. The values of carbon isotope of individual amino acids in studied shales indicate that organic matter of Timano-Pechora domanik rocks is composed primarily of the marine type of organic matter.

Keywords: amino acids, domanik shale, kerogen, carbon isotope of individual amino acids.

DOI: 10.19110/2221-1381-2016-8-27-32

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