Geological structure and conditions of formation of Strizhkovskoe barite-polymetallic deposit (Ore Altai)

Strizhkovskoe barite-polymetallic deposit is a typical medium-low-temperature hydrothermal-metasomatic deposit. It's located within north-west part of Zmeinogorsk-Bystrushinskiy downfold; host rocks are volcano-terrigenous Devonian rocks. Ore bodies are related to sublatitudinal and submeridional faults intercrossing. Wallrock quartz-chlorite-sericite metasomatites formed prior to ores formation. Ore mineralization process began in Middle Devonian. Main ore minerals are sphalerite, galena, and chalcopyrite. Also there are gold and silver occurring as electrum, acanthite; silver is present in fahlores as an isomorphous admixture. Formation of the deposit subdivides into two main stages and five phases; according to obtained results of isotope study of the sulfides, it's possible to conclude that there was a mixed source of ore matter (mantle source replacing with crust source). The temperature of main ore formation stage varied form 230 to 180 degrees. Solutions salinity varied from 9 to 15 % wt of NaCl equiv. According to fluid inclusions study results, the solutions consisted of water and following compounds CO2, NH3, SO2, HCO3

Mineralogy and prospect of noble metals of gold-bearing ore breccias from ore fields of polymetallic deposits of Ore Altai

The object of the present study are the ore-bearing breccias of the worked-out lower-middle Devonian gold-silver barite-polymetallic Zmeinogorsky deposit belonging to the cognominal ore district and the conserved massive sulfide Chekmar deposit belonging to the Leninogorsk ore district. Both ore districts occupy an adjacent position within the northeastern depression zone of the Ore Altai megatrough. A brief structural and geological description of near-fault ore-bearing breccias, which developed within the peripheral parts of the deposits, is given. Analysis of petrographic composition of breccia fragments and their cementing material allowed to define barite-quartzite breccias of the Zmeinogorsky deposit and pyritized adularia-quartz metasomatites formed upon acidic igneous rocks and greenschists of the Chekmar deposit. Results of mineralogical studies with use of raster electron microscope show that there are ore minerals microinclusions in the detrital material and cement of breccias. Barite-quartzite breccias of Zmeinogorsk deposit contain barite, galena, Hg and Sb containing polymineral formations, tetrahedrite-boulangerite, bromargyrite, leucoxene. Microquartzites of these breccias mostly consist of quartz. Chekmar deposit ore breccias detrital material contains pyrite, barite, arsenopyrite, galena, sphalerite, zircon, titanite, leucoxene and REE minerals. Quartzitic compound of these breccias is cryptocrystalline and consists of quartz and adularia with admixtures of sericite and pyrite. Due to results obtained by use of SEM it was stated that barite, sulfides and sulfosalts of breccias contain noticeable amounts of dissipated Au, Pd, Pt, Ir. ICP-MS results confirm that studied ore breccias contain such noble metals as Au, Ag, Pd, Pt. Moreover, noble metals contents in Zmeinogorsk deposit breccias reach industrial standards while noble metals of Chekmar deposit ores can be extracted along with the processing of basic massive sulfide ores. Further study of ore breccias is important as these breccias can be considered as a noble metals containing subformation among polymetallic ores of Ore Altai

Barite-polymetallic mineralization of Zmeinogorsk ore district and some genetic aspects of its formation

Zmeinogorsky ore district is located in the northwest part of Ore Altai megatrough, which has long-lasting history of its development and complicated geological structure. Within the ore district, which is the northwest part of the devonian Zmeinogorsk-Bystrushinsky trough, ore mineralization is associated with the system of northwest border faults and cross branch faults

U-Pb geochronology of subvolcanic and pyroclastic formations of the Zmeinogorsk barite-polymetallic deposit (Rudny Altai)

Schemes of Zmeinogorsk ore field structure made in 1996, 1960 and 1949 have been analyzed. The schemes differ from each other in contents and prospecting trends. This study is based on the 1949 scheme, made on the basis of the results of extensive mining and drilling operations. Based on the analysis of stratigraphy, LA-Q-ICP-MS dating results by U-Pb method, rocks composition, plicative and disjunctive dislocations of sedimentary, volcanic and subvolcanic formations, as well as their relationship, an updated scheme of Zmeinogorsk ore field structure is suggested. It belongs to rhyolite dome-type, which is also charactered to the neighboring Leninogorsk ore distric

Statistical Mechanics of Stress Transmission in Disordered Granular Arrays

We give a statistical-mechanical theory of stress transmission in disordered arrays of rigid grains with perfect friction. Starting from the equations of microscopic force and torque balance we derive the fundamental equations of stress equilibrium. We illustrate the validity of our approach by solving the stress distribution of a homogeneous and isotropic array.Comment: 4 pages, to be published in PR

Statistical Mechanics of Vibration-Induced Compaction of Powders

We propose a theory which describes the density relaxation of loosely packed, cohesionless granular material under mechanical tapping. Using the compactivity concept we develope a formalism of statistical mechanics which allows us to calculate the density of a powder as a function of time and compactivity. A simple fluctuation-dissipation relation which relates compactivity to the amplitude and frequency of a tapping is proposed. Experimental data of E.R.Nowak et al. [{\it Powder Technology} 94, 79 (1997) ] show how density of initially deposited in a fluffy state powder evolves under carefully controlled tapping towards a random close packing (RCP) density. Ramping the vibration amplitude repeatedly up and back down again reveals the existence of reversible and irreversible branches in the response. In the framework of our approach the reversible branch (along which the RCP density is obtained) corresponds to the steady state solution of the Fokker-Planck equation whereas the irreversible one is represented by a superposition of "excited states" eigenfunctions. These two regimes of response are analyzed theoretically and a qualitative explanation of the hysteresis curve is offered.Comment: 11 pages, 2 figures, Latex. Revised tex

Вычислительный подход и программный пакет RNAexploreR для группировки молекул РНК генов человека по их экзонным признакам

The study on the exon combinatoric rules of human genes during the process of splicing is of great interest for the diagnosis and treatment of cancer. A certain part of the research is aimed at developing reliable prediction models for global exon combinatorics during the formation of mature RNA. The primary task is to develop standards or uniform systematic statistical approaches to the analysis and interpretation of possible exon sequences of genes.A computational approach is proposed to group alternative splicing events in primary messenger RNA of human genes with the aim of determining the gene correspondence or molecule class. The method consists of reducing the dimension of the exon feature space and combining closely located exons into a limited number of classes, replacing the exon pathways of RNA generation with sequences of corresponding exon class labels, calculating the distances between RNA transcripts by some measure of similarity, and associating closely spaced RNA objects into clusters. The performance evaluation of developed algorithms has been done using the examples of RNA molecules of selected nonhomologous human genes and human hybrid oncogene RUNX1/RUNX1T1. The mean accuracy of the assignment of the transcript to given gene is about 99,5 % for the considered nonhomologous pairs of genes.A software package and web application RNAexploreR, integrating the implemented algorithms for the analysis of alternative splicing of human gene RNA products, have been developed. The proposed algorithms and software can be used to study the organization and functioning of both aberrant and normal human genes.Изучение правил комбинаторики экзонов генов человека во время сплайсинга представляет огромный интерес для диагностики и лечения раковых заболеваний. Определенная часть исследований направлена на разработку надежных моделей предсказания глобальной комбинаторики экзонов при образовании зрелой РНК. Первоочередной задачей является разработка стандартов или единых систематизированных статистических подходов к анализу и интерпретации возможных экзонных последовательностей генов.Предложен вычислительный подход к предсказанию событий альтернативного сплайсинга в первичных мРНК генов человека, методика которого состоит в снижении размерности пространства экзонных признаков и объединении близко расположенных экзонов в ограниченное число классов, замене экзонных путей генерации РНК на последовательности соответствующих меток классов экзонов, вычислении расстояний между транскриптами РНК по некоторой мере сходства, объединении близкорасположенных объектов РНК в кластеры. Проверка работоспособности разработанных алгоритмов выполнена на примере наборов молекул РНК отобранных негомологичных генов человека и гибридного онкогена RUNX1-RUNX1T1 человека. Точность предсказания разработанного подхода составляет 99.5% для рассмотренных негомологичных пар генов.Разработан программный пакет и веб-приложение RNAexploreR, интегрирующие реализованные алгоритмы анализа альтернативного сплайсинга РНК-продуктов генов человека. Предложенные алгоритмы и программное обеспечение могут быть использованы для изучения организации и функционирования как аберрантных, так и нормальных генов человека

Genesis of precious metal mineralization in intrusions of ultramafic, alkaline rocks and carbonatites in the north of the Siberian platform

The gold and platinum-group elements (PGE) mineralization of the Guli and Kresty intrusions was formed in the process of polyphase magmatism of the central type during the Permian and Triassic age. It is suggested that native osmium and iridium crystal nuclei were formed in the mantle at earlier high-temperature events of magma generation of the mantle substratum in the interval of 765–545 Ma and were brought by meimechite melts to the area of development of magmatic bodies. The pulsating magmatism of the later phases assisted in particle enlargement. Native gold was crystallized at a temperature of 415–200◦C at the hydrothermal-metasomatic stages of the meimechite, melilite, foidolite and carbonatite magmatism. The association of minerals of precious metals with oily, resinous and asphaltene bitumen testifies to the genetic relation of the mineralization to carbonaceous metasomatism. Identifying the carbonaceous gold and platinoid ore formation associated genetically with the parental formation of ultramafic, alkaline rocks and carbonatites is suggested

Experimental and computational studies of jamming

Jamming is a common feature of out of equilibrium systems showing slow relaxation dynamics. Here we review our efforts in understanding jamming in granular materials using experiments and computer simulations. We first obtain an estimation of an effective temperature for a slowly sheared granular material very close to jamming. The measurement of the effective temperature is realized in the laboratory by slowly shearing a closely-packed ensemble of spherical beads confined by an external pressure in a Couette geometry. All the probe particles, independent of their characteristic features, equilibrate at the same temperature, given by the packing density of the system. This suggests that the effective temperature is a state variable for the nearly jammed system. Then we investigate numerically whether the effective temperature can be obtained from a flat average over the jammed configuration at a given energy in the granular packing, as postulated by the thermodynamic approach to grains.Comment: 20 pages, 9 figure