A.A. Borovikov1, V.A. Goverdovskii2, A.S. Borisenko1,3, N.V. Bryanskii4, S.I. Shabalin1,3 1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Metally Altaya Joint-Stock Company, prosp. Kommunisticheskii 99, Gorno-Altaisk, Altai Republic, 649002, Russia 3Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia 4A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia
Keywords: Mo-W deposits, fluids inclusions, redox potential, metal-bearing ore-forming fluids
Based on results of study of fluid inclusions, we have established the specific fluid regime of formation of the Kalguty Mo-W(Be) deposit (Gorny Altai). Using classical thermobarogeochemistry (cryo- and thermometry) and modern microprobing methods (Raman spectroscopy and LA-ICP-MS), we studied fluid inclusions in samples of quartz of quartz-wolframite veins (ore formation stage I), specific “quartz core” (quartz lens), and pyrite-chalcopyrite-molybdenite paragenesis (ore formation stage II). The results of study show that the quartz-wolframite veins of the Kalguty deposit formed with the participation of reduced W-Sb-bearing fluids with a salt content of up to 5.9 wt.%. Their gas phase consisted of CO2, N2, and CH4. Formation of pyrite-chalcopyrite-molybdenite mineralization involved oxidized hot (530-420 ºC) fluids with the average salt content of 9.3 wt.%. Their gas phase was of high density (up to 0.55) and consisted of CO2, N2, and H2S. The pressure of the mineral-forming environment varied from 50 to 25 MPa. The fluids contained Cu, Mo, Bi, and S. The productive greisen-vein Mo-W(Be) mineralization of the Kalguty deposit resulted from the superposition of greisen molybdenite-chalcopyrite mineralization on parageneses of earlier formed quartz-wolframite veins. Oxidized metal-bearing fluids that formed the Mo mineralization of the Kalguty deposit have high contents of S and are geochemical analogs of magmatic metal-bearing ore-forming fluids of the Central Aldan porphyry Cu-Au-Mo deposits, which are genetically related to alkaline massifs. This suggests the significant influence of the mantle source on the formation of the Kalguty rare-metal ore-magmatic system. The same is evidenced from the sulfur isotope composition of chalcopyrite, molybdenite, and pyrite from ore parageneses, falling in the narrow range of δ34S‰ from -1.2 to +2.9 corresponding to the isotope composition of mantle sulfur.
L.I. Panina, A.T. Isakova
V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Apatite, ijolite veins, exocontact aegirinites, silicate and silicate-salt inclusions, alkali sulfate-carbonate and carbonate inclusions
Having applied methods of comprehensive melt inclusion studies, we have elucidated the formation conditions for one of the largest apatite deposits in the Maimecha-Kotui province, located in the exocontact zone of the Magan alkaline ultramafic carbonatite massif, in apoquartzite fenite-aegirinites. We examined the most P-enriched exocontact nepheline-containing aegirinites and ijolite veins in them. In veined ijiolite, primary silicate-salt melt inclusions in nepheline and syngenetic primary silicate, alkali sulfate-carbonate, and carbonate melt inclusions in apatite were found. Primary alkali sulfate-carbonate melt inclusions were also identified in apatite from exocontact nepheline-containing aegirinites. Detailed analysis of the inclusions has shown that nepheline of the apatite-containing ijolite veins crystallized at 1100-1120 ºC from homogeneous nephelinite melt, which was enriched in SO3, Cl, CO2, and H2O and locally contaminated with quartz sandstones and quartzites. At lower temperatures (either at the final stages of nepheline crystallization or at the early stages of apatite formation), the melt was already heterogeneous (probably, because of immiscibility) and consisted of more Si-saturated, alkali sulfate-carbonate, and carbonate fractions. Apatite crystallized mainly from separated alkali sulfate-carbonate melts: at 1080-980 ºC in veined ijolites and at 940-760 ºC in aegirinites. Alkali sulfate-carbonate melts in veined ijolites were enriched in SO3 but depleted in P as compared with those in aegirinites. At the final stage, apatite crystallized from P-poor carbonate melts.
R.G. Kravtsova, Yu.I. Tarasova, A.S. Makshakov, L.A. Pavlova
A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia
Keywords: Gold, silver, associated elements, modes of occurrence, sediment streams, formation conditions
We studied the distribution and modes of occurrence of the main (Au and Ag) and major associated elements indicating mineralization (Hg, Sb, As, Pb, Zn, and Cu) in samples of loose sediments fr om lithochemical sediment streams of Au-Ag zones at the Dukat deposit. The major mineral and nonmineral modes of occurrence of elements indicating Au-Ag mineralization have been detected with POLAM-312 and POLAR-3 ore microscopes and by X-ray electron probe microanalysis with Superprobe 733 and JXA 8200 (JEOL, Tokyo, Japan) microprobes. The distribution and modes of occurrence of ore elements in the loose (alluvial) sediments of streams draining the Au-Ag zones are closely related to the ore composition. As in the ores, the main elements indicating mineralization are Au and Ag, while the major associated elements are Hg, Sb, As, Cu, Pb, and Zn. Gold in alluvial sediments occurs as electrum, fine (dispersed, ultradispersed, and colloid-dispersed) particles, and the so-called “bound” (predominantly with sulfides) invisible Au (sorption component and its derivates). Silver occurs not only as hypergene forms, microinclusions, and ultrasized particles but also in native form and as partly preserved sulfides and sulfosalts. The other elements (Hg, Sb, As, Pb, Zn, and Cu) are observed as secondary minerals of complex composition and differently preserved corroded fragments of pyrite, chalcopyrite, galena, and sphalerite grains, dominated by oxides and hydroxides (mainly those of iron). Salts and water-soluble sulfates of Fe, Cu, Pb, and Zn are less widespread. In study of the conditions of sediment stream formation in cryolithogenesis zones, wh ere physical weathering is regarded as the major process, chemical factors (first of all, chemisorption) should also be taken into account. This is proven by the enrichment of “fine” loose material in Au, Ag, and ore elements in general. The high percentage of mobile forms of elements, which are easily leached out by ordinary acids, in ores and aureoles, together with the widespread occurrence of clay minerals and hydroxides, has a significant influence on chemisorption. For example, the portion of fine and “bound” Au, the element considered to be the least prone to chemical weathering, reaches 50-60% in the riverbed sediments of the stream head. Native Au (electrum) makes up 40-50%. The material is diluted during its transport. As Au content decreases, the portion of fine and “bound” Au in the sediment stream increases to 95%. Evidently, these two Au forms are predominant in streams as compared with ores. The modes of occurrence of elements indicating Au-Ag mineralization in secondary environments, as in primary ones, serve as an effective criterion for assessment of the potential of geochemical anomalies detected in sediment streams. They are a reliable indicator of ore associations, which is of practical significance. We think that modes of occurrence can sometimes be used to estimate the erosion level of drained zones and sites (i.e., to predict mineralization to depth). This criterion can be successfully applied at all stages of geochemical study of ore-bearing areas, from the prediction of the potential of anomalies detected in sediment streams in poorly studied areas to the detailed exploration of known ore objects.
Clinopyroxene binary solid solutions in the systems diopside-hedenbergite, diopside-aegirine, and hedenbergite-aegirine have been synthesized. Based on data from X-ray diffraction studies, the unit-cell parameters of these solid solutions have been refined, and their concentration dependences have been established. These clinopyroxene series are near-ideal continuous solid solutions. The partition of Mg and Fe between the diopside-hedenbergite binary solid solutions and biotite of the phlogopite-annite series was studied by the method of cation exchange equilibria at 650 and 750 ºC and 2 kbar. The application of KF solution as a reaction medium permitted achieving equilibrium in a considerably shorter time and from its both sides. The partition of Mg and Fe is near-ideal within the experimental error. The experimental results were compared with results of calculations based on literature data on the thermodynamic properties of pure end-members.
I.V. Korovnikov1,2, Yu.Ya. Shabanov3 1A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia 3Siberian Research Institute of Geology, Geophysics and Mineral Resources, Krasnyi pr. 67, Novosibirsk, 630091, Russia
Keywords: Biostratigraphy, trilobites, Kuonamka Formation, Siberian Platform
A study of triobite distribution allowed a biostratigraphic subdivision of the Kuonamka Formation section exposed in the middle reaches of the Olenek River (18 km downstream of the village of Olenek). Through detailed description of the section, a biostratigraphic subdivision down to the level of biozones and faunal beds was performed. These are beds with Calodiscus-Triangulaspis annio , Delgadella ultima-Bergeroniellus expansus Zone, Lermontovia dzevanovskii-Neopagetina orbiculata Zone, Anabaraspis Zone, Cheiruroides arcticus-Pagetia horrida Zone, Kounamkites Zone, Triplagnostus gibbus Zone, and beds with Tomagnostus fissus-Paradoxides sacheri . These biostratigraphic subdivisions were correlated with regional zones of the Siberian Platform. The study also provides analysis of trilobite assemblages from the Lower/Middle Cambrian boundary interval, which was identified in the studied section and other previously described sections (Nekekit, Molodo, Boroulakh Rivers). In the studied section, the base of the Middle Cambrian is defined by the FAD of Cheiruroides arcticus , i.e., at the base of the Cheiruroides arcticus-Pagetia horrida Zone. This level correlates with a presumed lower boundary of Stage 5 of a new International Stratigraphic Chart for the Cambrian System.
L.B. Khazin1, I.V. Khazina1, S.K. Krivonogov2,3, Ya.V. Kuzmin2,4, A.A. Prokopenko5, S. Yi6, G.S. Burr7 1A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 3Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia 4Tomsk State University, ul. Lenina 35, Tomsk, 634050 Russia 5University of Cologne, 100 Albertus-Magnus-Platz, D-50923, Cologne, Germany 6Korean Institute of Geoscience and Mineral Resources, Gwang-ro 124, Yuseong-gu, 305-350, Daejeon, South Korea 7University of Arizona, Tucson, AZ 85721, USA
Keywords: Ostracods, Holocene, paleontology, climatostratigraphy, paleoecology, southern West Siberia
The study presents a summary of the latest data on ostracod microfaunas from Middle-Upper Holocene lacustrine deposits of southern West Siberia collected from lakes Malye Chany, Bol’shaya Lozhka, Beloe, and paleolake Chicha. A total of 28 ostracod species were identified. The identified ostracod assemblages reveal local variations in the lake ecosystems as well as general trends, which can be correlated with both regional and global climate changes. A cooling episode during the second half of the Subboreal is marked by the transition from a warm-water mesohaline assemblage to cold-water candonid ostracods at ca. 3.4 cal ka BP. The widespread occurrence of mesopolythermophilic ostracod species at 1.9-0.6 cal ka BP indicates the end of cooling and lowering of lake-water level. From 0.6 cal ka BP to present, the ostracod assemblages area characterized by the high specific diversity, which is probably an indication of the increased variability of aquatic ecosystems due to fluctuations in salinity and water levels of the lakes. Climate changes identified by ostracod assemblages are consistent with the climatic trend constrained by early palynological studies.
The speed of sound in liquid
and gaseous refrigerant R-407C
was measured by the method of ultrasonic interferometer in the temperature
range from 293 to 373 K and pressure from 0.05 to 0.5 to 3.7 MPa. The experimental uncertainties of the temperature,
pressure, and speed of sound measurements were estimated to be within ±20 mK, ±4 kPa, and ±(0.1–0.3) %, respectively. The obtained results are
compared with the calculated speed of sound from the fundamental state equation for the Helmholtz free
energy.
The effect of parameters of the multi-ring
Couette system with counter rotating coaxial cylinders on the process
of thermal energy release in a viscous liquid filling this system is
considered with regard to the problem of determining the possibility
of creating the high-performance wind heat generator.
The multi-cylinder rotor design allows directly conversion of the mechanical
power of a device consisting of two “rotor” wind turbines with
a common axis normal to the air flow into the thermal energy in
a wide range of rotational speed of the cylinders. Experimental
results on the measurement of thermal power released in the pilot
heat generator at different relative angular speeds of cylinder rotation are
presented.
A
formula for evaluating the gas-flow exergy at heat supply/removal without
concretization of the process and the way in which the dissipation of
kinetic energy proceeds is reported.
January
28, 2016 is the 100th anniversary of the birth of the outstanding researcher in
the field of power engineering, thermophysics and thermodynamics, great
scientist and brilliant organizer Academician Ivan I. Novikov (15(28) January
1916-30 May 2014). Results of his fundamental research
are widely known in our country and abroad at the level of discoveries and
inventions.
