pdf № 289, January

DOI: 10.19110/2221-1381-2019-01-3-12

The North Kamennik low-sulfide Pt-Pd-deposit is associated with the North PGE Reef occurring in 800 m above the bottom of the West-Pana intrusion of the Paleoproterozoic Fedorova-Pana Layered Complex, Kola Peninsula. The main ore body of the deposit is accompanied by lower ore bodies that is very unusual for other sites of the reef (e.g., Kievey deposit). The lower ore bodies having a different composition of host lithology and geochemical features are divided into three types. Results of mineralogical research allow defining each type using an assemblage of PGE minerals: stannide-telluride (type 1), arsenide-sulfide-telluride (type 2) and sulfide-telluride (type 3). Mineralogical finds have been made within the ore bodies of stannide-telluride and arsenide-sulfide-telluride PGM assemblage and are presented by arsenopalladinite, isomertieite and kojonenite (new minerals for the North Reef).

Keywords: West-Pana intrusion, North Reef, platinum group elements, platinum group minerals.

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DOI: 10.19110/2221-1381-2019-01-13-19

The article examines the composition and structure of the Lower Carboniferous part of the Yajyu Suite, common in the eastern subzone of the Lemva structural-formational zones of the Polar Urals. It is an indicator of the beginning of collision processes in the northern part of the Urals and reflects the geological history of this period. The scaly-thrust structure of the area, small isoclinal folds, numerous discontinuous disturbances, and redeposition of organic remains strongly obscured the succession of layers. The revealing of the lithological benchmark allowed to decipher the geological structure of one of the tectonic «scales» (plates) and to clarify the sequence of the Lower Carboniferous deposits in it.

The section of the Yajyu Suite presented alternating packs of carbonate-terrigenous and carbonate rocks. The first ones were formed by underwater density flows; the second ones represented hemipelagic deposits. Their alternation in the section indicates the repeated change of hydrodynamically quiet sedimentation conditions with catastrophic. The composition of detrital material of carbonate-terrigenous and carbonate rocks of the Yajyu Suite on the Grubeyu River testifies to existence of shallow-water carbonate shelf in the east of the sedimentation basin (in modern coordinates) in the Early Carboniferous time.

Keywords: Urals, Lemva zone, Lower Carboniferous deposits, Yajyu Suite, sedimentary rocks, stratigraphy, lithological benchmark.

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DOI: 10.19110/2221-1381-2019-01-20-28

The study of seismicity of low-magnitide areas is relevant in connection with their geodynamic activation, as well as the location of critical objects within the platform, when even a weak seismic event can cause serious damage. The purpose of this work is to determine parameters of earthquakes of 2008 and 2009, the seismotectonic position of hypocenters, and to compare them with calculations of other seismological services. As a result of instrumental data processing in the WSG and NAS programs, the following earthquake parameters were obtained on September 22, 2008: t0 = 23h21m00.5s, 61.276N, 51.580E, Rminor = 6.2 km, Rmajor = 21.0 km, Azmajor = 30°, h = 10f km, Кр = 9.4/2, ML = 3.2/2, Ms = 2.9/2. According to our calculations, it occurred in the Kortkeross region of the Komi Republic. Parameters of the earthquake on October 20, 2009: t0 = 04h45m43.9s, 57.777N, 50.364E, Rminor = 6.6 km, Rmajor = 24.0 km, Azmajor = 20 °, h = 5 km, Kp = 9.8/3, ML = 3.4/3, Ms = 2.6/2. The epicenter was located in the Nemsky district of the Kirov region. Tectonically, the earthquakes of 2008, 2009 occurred in the area of the Kirov-Kazhim aulacogen of the Volga-Ural anteclise. The earthquakes of the northeast of the Russian Plate are mainly associated with aulacogen and the adjacent arches. The recorded seismic events confirm that the aulacogen is an active seismic-generating structure.

Keywords: earthquake, epicenter, bulletin, seismicity, East European Platform, Russian Plate, aulacogen.

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DOI: 10.19110/2221-1381-2019-01-29-34

In the article the geological-geomorphological and climatic conditions of mudflow formation in the south-eastern slope of the Lesser Caucasus on the example of the Terterchay River are researched and their activity under climate change conditions is estimated. According to the carried mudflow mass the mud flows are subdivided into water-stone flows, low-stability rocks are involved in the geological-geomorphological structure of the basins. Investigation of the Terterchay River basin, based on the materials of interpretation of space images (SI), revealed the degree of mudflow risk and the type of mudflows. The article also analyzed meteorological conditions that caused mudflows in the basin of the Terterchay River. Quantitative indicators of mudflow-forming rain were revealed. The vertical distribution of abundant precipitation with a daily sum of ³ 20 mm was investigated. The connection of the mudflows with macrocirculation processes over Europe and Western Siberia was established. To do that types of circulation according to G.Ya. Wangengheim and B. L. Dzerdzeevsky were used.

Keywords: mudflow, mudflow hazard, interpretation, space image, atmospheric circulation, activity, anthropogenic impact, meteorological conditions.

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DOI: 10.19110/2221-1381-2019-01-35-43

We have studied typomorphic features of alluvial gold from alluvial deposits of the Frolovsky region (Ust‘-Kulom district, Komi Republic). We revealed main characteristic features of native gold: morphology, geochemical features, mineral inclusions and accompanying minerals. We found that the golden particles had heterogeneous composition. The inner parts of the particles were characterized by an irregular distribution of Ag impurities (up to wt. 14.83 %). All particles had high weight Au content. The mineral composition of the heavy fraction was described representing a wide spectrum of specific minerals of metamorphic and magmatic associations pointing to presence of two different source provinces for alluvial deposits of the Frolovsky region. The typomorphic features of the placer gold of the region indicated its belonging to the gold-quartz formation and the proximity of the source, presumably associated with intermediate collector of the Permian age.

Keywords: alluvial gold, morphology, granulometry, internal structure, chemical composition, microinclusions.

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DOI: DOI: 10.19110/2221-1381-2019-01-44-57

In memory of the outstanding Russian geological prospectus and pioneer of many gold-placer deposits and locations of the fossil detritus of the Pleistocene mega-mammals with examples illustrating and confirming the validity of his ideas in the field of geotechnologies of prospecting, evaluation and processing of mineral deposits.

Keywords: Alexandr Andreevich Kotov, intellectual heritage, forecast, searches and estimation of ore deposits.

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