Pegmatoid objects in a sample of the Kaidun meteorite

We report the results of textural and mineralogical investigations of fragment #d(3–8)B of the Kaidun meteorite. The fragment is represented by six polished thin sections obtained by sequential sawing of a meteorite sample. Its main mineral is magnesian olivine; pyroxenes, augite and enstatite, are less abundant. The minor minerals are Fe-Ni sulfides, and the accessory minerals are chromian magnetite and apatite. The minerals show highly variable compositions. Several lithological types of material were distinguished on the basis of texture and composition. A characteristic feature is the presence of fractures, whose walls are enriched in olivine and, occasionally, sulfides. Some fractures contain relatively large euhedral crystals of zoned olivine. Olivines occurring on the walls of fractures and within fractures show a negative correlation between Mg# values and nickel content. The fragment has been subjected to multiple impact events. The material of the fragment bears evidence for intense multistage metasomatic alteration with the influx of olivine material and formation of pegmatoid-type segregations. This process has never previously been observed in meteorites, but is quite common in terrestrial massifs. The results of this study are in good agreement with our hypothesis that Phobos is the parent body of the Kaidun meteorite and indicate a possible Martian origin for Kaidun fragment #d(3–8)B.     

Influence of Atlantic Water on the Sea Ice Cover in the Western Arctic in Winter

The results of temperature and salinity measurements in the upper 1000-mlayer of the Nansen Basin in the Arctic Ocean made from the North Pole-35 drifting station in winter of 2007/2008 are analyzed. The uniqueness of the dataset processed is defined by the station drift path in the Nansen Basin and by the time of the drift which immediately followed the record decline of Arctic sea ice in September 2007. It is found that the maximum heat flux from the ocean to the ice cover equal to more than 90 W/m² was observed in the area of Atlantic water in flow between Spitsbergen and Franz Josef Land. It was caused by the drift velocity increase and by the corresponding deepening of the Ekman boundary layer. No significant changes (as compared to climate normals) in the influence of ocean heat on the ice cover in the eastern Nansen Basin in winter were registered.     

Structural Connections between the Urals and Western Siberia: A Common Stage of Formation at the Permian–Triassic Boundary

Doklady Earth Sciences - The 40Ar–39Ar dating of mica from schists and blastomylonites, sampled within the limits of a fault that separates the Eastern zone of the Middle Urals, sinking...     

Remote Evaluation of Albedo Using Photorecording Equipment

Izvestiya, Atmospheric and Oceanic Physics - We developed and tested the method for determining the surface albedo using photorecording devices and solar radiation equipment. Our method is based on...     

Modeling of wind upwellings on the northwest shelf of the Black Sea near local features of the bottom topography

We discuss the results of numerical experiments aimed at the investigation of the process of formation of the three-dimensional structure of the zones of upwelling on the northwest shelf of the Black Sea depending on the direction of the wind. We perform the detailed analysis of three zones (I, II, and III) with fairly well pronounced inhomogeneities of the bottom topography. Zone I is located in the north part of the shelf and, in this region, we observe a narrow depression to the southwest of the Tendrovskaya Spit. In zone II located in the near-Danube zone, we observe a height reaching the sea surface (Zmeinyi Island). Zone III is located in the east part of the shelf and corresponds to a sharp drop of depths with specific curvature of the coastal line of the Kalamitskii Bay and Gerakleiskii Peninsula. The performed analysis enables us to conclude that, in the vicinity of the local features of the bottom topography and coastal line (such as underwater heights, depressions, and capes), we observe the appearance of the zones of upwelling of waters, especially pronounced in the deep-water layers of the sea. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 68–80, May–June, 2008.     

Simulation of surge phenomena and transformation of the admixture field in the Sea of Azov in the presence of stationary currents

Using a three-dimensional nonlinear mathematical model, we study the processes of transfer and diffusion of contaminants in the Sea of Azov in the presence of stationary currents. Changes in the sea level, surge phenomena, and the direction and velocity of stationary currents caused by winds with different maximum velocities are analyzed. We estimate the region of applicability of the linear approximation and the choice of the value of integration steps over space and time coordinates. It is shown that the growth of the maximum wind velocity increases the contaminated domains and the time of complete dispersion of the admixture. Solutions obtained in the linear approximation differ slightly from those obtained by using the nonlinear model for wind velocities up to 5 m/sec. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 52–68, July–August, 2008.     

Investigation of the influence of wind action upon the currents and propagation of impurities in the azov sea

The surge phenomena and currents in the Azov Sea caused by variable winds in the presence of stationary currents are studied by using a three-dimensional nonlinear mathematical model. The specific features of the transformations of impurities in the water area of the Azov Sea under the joint action of stationary and nonstationary winds are investigated. On the basis of the results of numerical calculations, we make conclusions concerning the dependence of the period of dissipation of impurities on the wind velocity and the location of the regions with impurities. It is shown that the variable wind significantly increases the deviations of the sea level and the area of distribution of the impurity as compared with the action solely of the stationary currents.     

Online Publication of Tiltmeter Data Based on the SeedLink Protocol

The main goal of this work is to provide real-time access to the data of the NSH tunnel tiltmeters via the Internet. Software is developed that solves this problem and also provides real-time visualization and archiving of data. The solution is based the specialized real-time protocol SeedLink, which ensures lossless data delivery with minimal transmission overhead. In order to simplify access to the device via IPv4 and to protect data from unauthorized access, a secure channel based on virtual private networks has been used. The solution was tested on two tiltmeters installed in the building of the Institute of Physics of the Earth, Russian Academy of Sciences (IPE RAS). Further device testing with an unstable power supply and communication conditions is planned. Therefore, the developed software was ported to energy-efficient ARM computers. Data transmission tests were carried out in the local IPE RAS network and in the wireless network of a mobile network operator. Real-time visualization of data from both tiltmeters and access to the archive are provided in addition to real-time access to data on the IPE RAS website.     

Event-scale pebble mobility observed by RFID tracking in a pre-Alpine stream: a field laboratory

Understanding coarse sediment transport is crucial for the prediction of sediment migration and the consequent development of fluvial morphologies. In this study, cobble displacements in a pre-Alpine creek have been recorded by means of radio frequency identification (RFID). Pebble monitoring has been systematically performed after each rainfall event with moderate precipitation, in order to exclude the superimposition of sediment displacements induced by triggering factors acting at different times. The analysis of the collected data was carried out through the application of both a principal component analysis and the Buckingham Π theorem. The experimental trends were interpreted considering the ratio of mobile pebbles, the pebbles' displacement and virtual velocity as the dependent variables. These quantities mostly depend on the event peak discharge, with a nonlinear increase of the travelled distance and a growth of up to two orders of magnitude of the virtual velocity (for an approximately 10× increase in peak discharge). An inverse dependency of the virtual velocity on the event duration was also observed. A comparison of the results obtained with those from laboratory investigations of bedload transport mechanics evidenced the differences in parametric trends associated with sediment mobility in the two environments. This contrast brings forward the combination of multiple drivers of sediment mobility, such as local morphology, sediment dimensions and flow unsteadiness, warranting a further in-depth investigation. Representation of results in a dimensionless form is suggested as a good practice to analyse data from case studies characterized by different scales. © 2019 John Wiley & Sons, Ltd.     

The generation of intensive short-period internal waves in the frontal zone of a coastal upwelling

The measurements data provided by an antenna of distributed temperature sensors, mounted on an oceanographic tower in the South Crimea continental shelf area, were applied to study the mechanism for the generation of short-period internal waves with anomalous amplitudes in the Black Sea. For analysis, information was incorporated concerning the background hydrological and meteorological conditions that were observed during the experiment. A mathematical model for the phenomenon under study has been constructed, and calculations of the anomalous internal wave generation have been presented. The paper contains a comparative analysis of thein situ data and simulation results, and demonstrates a good qualitative/quantitative agreement between the parameters of internal waves. Translated by Vladimir A. Puchkin.