Material composition of the basalt-trachyte series of the early Devonian of the Saralin graben-rift

The article clarifies the structural-tectonic position of the Saralin graben. It is determined that, along with the Balyksinsky graben located to the south and the Goryachegorsky volcanic plateau to the north, they are the connecting structural links between the Kuznetsk-Alatau alkaline province and the adjacent Minusinsk trough. In the early Devonian, the alkaline province was formed as a vaulted-block structure (the "shoulder" of the rift), and the Minusinsk deflection as a depression with the dominant volcanism in it. The boundary between these positive and negative structures was the deep Balyksinsko-Saralinsky fault

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

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

Comparative analysis of two groups of patients according to the results of cataract phacoemulsification in combination with silicone oil removal through flat part of the ciliary body and posterior capsulorhexis in the long term after retinal detachment surgery

Purpose. To conduct a comparative analysis of two groups of patients according to the results of cataract phacoemulsification in combination with the silicone oil removal through flat part of the ciliary body and posterior capsulorhexis in the long term after retinal detachment surgery.Material and methods. 30 patients with a diagnosis of cataract, avitria, tamponade of the vitreous cavity with silicone oil OXANE 5700 were under observation. Patients were randomly divided into two groups. In both groups, the infusion system was installed through port 25 Ga located 3–4 mm from the limb, cataract phacoemulsification was performed in the first stage. In the first group (15 patients), silicon oil was removed through the posterior capsulorexis using a curved aspiration cannula of caliber 18 Ga. In the second group (15 patients) silicon oil was removed using aspiration through the second port of 25 Ga.The assessment of the functional and anatomical state after surgery was based on data from visometry, autorefractometry, ultrasound B-scanning of the vitreous cavity, and optical coherence tomography of the macular area. Assessment of patient satisfaction with the subjective level of quality of life was carried out using the validated visual function questionnaire Visual Function (VF-14).Results. In both groups, on average, there was a significant increase in the best corrected visual acuity. According to B-scan data, emulsified silicone oil particles were less detected in patients after removal of silicone oil through posterior capsulorexis. The subjective level of quality of life of each patient impr oved significantly in both groups.Conclusion. Performing the combined operation of cataract phacoemulsification with the removal of silicone oil through the posterior capsulorhexis in comparison with the silicone oil removal through the flat part of the ciliary body can equally improve visual function. Satisfaction with treatment results was slightly higher in the group with silicone oil removal through posterior capsulorexis

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

Magmatism of the Devonian Altai-Sayan Rift System: Geological and geochemical evidence for diverse plume-lithosphere interactions

The geodynamic environment of the 407–392 Ma Altai-Sayan Rift System is characterized using previously published and new original data on whole rock, trace and Sr-Nd isotopic compositions, along with U-Pb zircon ages. Five magmatic associations are present: basalt (basalts and basaltic trachyandesites), continuous (basalts, andesites, dacite-rhyolites), alkaline (basalts, nephelinite, tephrite, phonotephrite, phonolite, teralite, ijolite-urthite, foyaite, nepheline and alkaline syenite), bimodal (trachybasalts, trachyrhyolites-pantellerites and peralkaline granites) and ultramafic-mafic (picrites and picrodolerites). Mafic rocks of basalt, continuous, alkaline, and bimodal associations exhibit a wide variation of TiO2 (from 1.05 to 4.05 wt%) and are compositionally intermediate between intraplate basalts of OIB type and basalts of active continental margins IAB type. The TiO2 content in these mafic rocks correlates directly with the content of large ion lithophile elements (LILE), rare-earth elements (REE), high field strength elements (HSFE), and particularly with Nb and Ta. The basaltic samples have positive εNd(395) values (+3.4 to +7.7) and a large range of εSr(395) values (−13.6 to +12.6). εSr(395) decreases with increasing TiO2 abundance. Pantellerites and alkaline granites have ore-level concentrations of Nb, Ta, Zr, Hf, REE; and they have similar Sr and Nd isotope parameters to those of the high-Ti basalts. This indicates their origin via fractionation of mantle magmas. Rhyolite samples are depleted in rare incompatible elements, but have low positive εNd(395) values (+1.5 to +1.8), and εSr(395) values (+16.6 to +20.6), and they compositionally resemble the rocks produced from anatectic magmas of crustal origin. Whole-rock elemental and isotopic data suggest that the mafic rocks were likely derived from lithospheric mantle that was metasomatized during the prior Caledonian accretion/subduction event. In combination with the field relationship and regional geology, our study suggests that the rock associations from the Devonian Altai-Sayan Rift System were derived by the activity of mantle plumes