Tracing the source of metals in Geogas from metal deposits in a loess-covered region北大核心CSCD

In order to test the distribution characteristics of metallogenic elements and the application effectiveness of the traee elements and REE for tracing the source of Geogas anomaly, the distribution characteristics of metallogenetic elements .trace elements and REE in different media of the Jiaolongzhang Pb-Zn deposit underneath the loess have been studied in this paper. Results indicate that the distribution characteristics of Geogas anomalous elements over the concealed orebodies are coincided with those of the enriched elements of ores, while the distribution characteristics of trace elements and REE in background Geogas samples are distinctly different from those of other media, indicating that the source of background Geogas materials is influenced by various factors( geological bodies, lab environment and blank reagent). The similar distribution characteristics of the trace elements in the Geogas samples of anomalous areas and in the ores suggested that Geogas anomaly is affected by concealed orebodies in depth. The difference between REE patterns of the Geogas samples of the anomalous area and those of other solid media might be caused by inadequate analytical precision and low collecting efficiency of the instrument. It is believed that the REE tracing method can provide the information on the source of Geogas anomaly if the analytical precision and collecting efficiency of REE could be constantly increased.     

The fluid phase evolution during the formation of carbonatite of the Guli massif: Evidence from the isotope (C,N, Ar) data

The first data on variations of the isotope composition and element ratios of carbon, nitrogen, and argon in carbonatites of different generations and ultrabasic rocks of the Guli massif obtained by the method of step crushing are reported. It is shown that early carbonatite differs significantly from the later ones by the concentration of highly volatile components, as well as by the isotope compositions of carbon (CO₂), argon, and hydrogen (H₂O). The data obtained allow us to conclude that the mantle component predominated in the fluid at the early stages of formation of rocks of the Guli massif, whereas the late stages of carbonatite formation were characterized by an additional fluid source, which introduced atmospheric argon, and most likely a high portion of carbon dioxide with isotopically heavy carbon.     

The possibility of passive acoustic monitoring of a Scuba Diver

The problem of controlling the state and location of scuba divers is of importance. This work consider the possibility to use for this purpose a low-frequency noise of a scuba diver. The noise of a scuba diver under a dry swimming suite near the trachea and in the water at a distance of 50 m was recorded.It wa shown that both sygnals are characterized by the presence of quasi-periodic components induced by the amplitude modulation of wide-band breathing noises by the brething rhythms of a scuba diver. The quasi-periodic componentss distinguished can be used to evaluate the physiological parameters of the state of a scuba diver and to establish his location.     

The effect of long-range atmospheric transport of organochlorine compounds by soil studies from Mongolia to the Arctic

The results of studies on the distribution regularities are presented for polychlorinated biphenyls (PCBs) of different degrees of chlorination and for organochlorine pesticides (OCPs): hexachlorobenzene (HCB), hexachlorocyclohexane (HCCH), and DDT with its metabolites in the soils along the Lena River valley and in background areas of Eastern Siberia and Mongolia. A statistically reliable correlation is found between the PCB–OCP and C_org concentrations. The highest levels of HCB are registered in the soils between 50 and 60° N. The concentrations of αand γ-HCCH increase reliably, while those of pp′-DDT and pp′-DDE decrease from south to north. A trend of the decrease in concentrations from Mongolia to the Laptev Sea is revealed for tri-, tetra-, and penta-chlorine-substituted PCB congeners. However, the soils sampled northwards from 60° N show a reliable increase in the concentrations of tetra-, penta-, and hexachlorine-substituted congeners.     

A new type of noble metal mineralization in the Northern Caucasus

The weathering crust of the Beden ultrabasite massif (the basin of Big Laba River) is identified and studied. Anomalously high contents of noble metals (Au, Pt, Pd) are revealed in the basal horizon of the Jurassic part of the weathering crust. For this reason we suspect an existence of a belt of noble metal miner-alization in the Paleozoic ultrabasites in the Peredovoi Range of the Northern Caucasus.     

Silurian U–Pb zircon age (LA-ICP-MS) of granitoids from the Zelenodol Cu–porphyry deposit,Southern Urals

The Zelenodol porphyry Cu-(Au, Mo) deposit located about 65 km SSW of the city of Chelyabinsk is confined to the western part of the West Uralian Volcanogenic Megazone. The concordant U-Pb age of zircons from ore-bearing island-arc diorite porphyryis 418.3 Â ± 2.9 Ma.     

New data on the level of contamination with tritium aerosol fallout in the nearest influence zone of the mining–chemical combine of the Rosatom State Corporation

The influence of tritium aerosol transport on radioactive contamination on the territory of the Krasnoyarsk region influenced by the mining–chemical combine of the Rosatom State Corporation was studied. Snow cover, foliage, and needles collected at various distances from the mining–chemical combine were selected as the object of this study. A new methodology of liquid extraction from plant material (leaves and needles) was worked out. As a result, the maximal concentrations of tritium (15 kBk/m³ in snow, 11 and 15 Bk/m² for leaves and pine-tree needles, respectively) were determined. However, the results obtained are not anomalous. Consequently, contamination with tritium may not be accounted for entirely due to the low concentrations.     

Tychite in mantle xenoliths from kimberlites: The first find and a new genetic type

Tychite Na₆Mg₂(CO₃)₄(SO₃) is a rare natural Na and Mg sulfatocarbonate. It is found only as minor mineral in deposits of saline lakes in the United States, Canada, Uganda, and China. In these continental evaporites tychite has sedimentary genesis. In this study, we report the first occurrence of tychite as a crystal phase in the melt inclusions in olivine from mantle xenoliths of the Udachnaya-East kimberlite pipe. This find provides an evidence for the probability of tychite crystallization from melts; i.e., this rare sulfatocarbonate may have a magmatic origin as well.     

Streaming potential near a hydrofracture

We suggest a mathematical model for the dynamics of the streaming potential near a hydrofracture of a seam after termination of water pumping into the fracture.     

Influence of the saffman force,lift force,and electric force on sand grain transport in a wind–sand flow

Quasi-horizontal trajectories of salting sand grains were found using high-speed video-recording in the desertified territory of the Astrakhan region. The sizes and displacement velocities of the saltating sand grains were determined. A piecewise logarithmic approximation of the wind profile in a quasi-stationary wind–sand flow is suggested, which is consistent with the data of observations and modeling. It was established that, in the regime of stationary saltation, the wind profile in the lower saltation layer of the wind–sand flow depends only slightly on the wind profile variations in the upper saltation layer. The vertical profiles of the horizontal wind component gradient in a quasi-stationary wind–sand flow were calculated and plotted. It was shown using high-speed video recording of the trajectory of a sand grain with an approximate diameter of 95 μm that the weightlessness condition in the desertified territory of the Astrakhan region in a stationary wind–sand flow is satisfied at a height of approximately 0.15 mm. The electric parameters of a wind–sand flow, which can provide for compensation of the force of gravity by the electric force, were estimated. In particular, if the specific charge of a sand grain is 100 μC/kg, the force of gravity applied to the sand grain can be compensated by the electric force if the vertical component of the electric field in a wind–sand flow reaches approximately 100 kV/m. It was shown that the quasi-horizontal transport of sand grains in the lower millimeter saltation layer observed in the desertified territory can be explained by the joint action of the aerodynamic drag, the force of gravity, the Saffman force, the lift force, and the electric force.