Use of digital terrain models in morphometric analysis of tectonic structures and prospecting of placers of alluvial genesis

Approaches have been developed to the application of the geomorphometric method for identification of neotectonic structures from maps of datum and summit planes by using the territory of Perm krai as an example. We carried out a comparative analysis of the resulting maps with existing neotectonic maps of local uplifts to reveal their good correlation. We substantiate the possibility of using the suggested approaches in forecasting deposits of sand-gravel raw materials.     

Sedimentary Rocks in the Basement of the Alpha–Mendeleev Rise,Arctic Ocean

Lithology and Mineral Resources - The results of petrographic, petrogeochemical and isotopic studies of sedimentary rocks obtained from bedrock outcrops of the Alpha–Mendeleev Rise, Arctic...     

On the Modeling of the Disruption of Cosmic Bodies at High-Speed Impacts

The results of the experimental study of the interaction of polyethylene impactors with a massive flat organic-glass target are presented. The impactor speed ranged from 3.2 to 5.84 km/s. A statistical analysis of the mass and size distributions of fragments of the impact and chop craters of the target is done. As a result, some scaling relations are established for the geometric size of the craters, the cumulative ejected mass, the mass of the largest fragment ejected from the impact crater, and for the dust mass. The mass distribution of the impact-crater fragments is shown to obey a power law and agrees well with other authors" data for some materials. The critical impact energy _k , resulting in the catastrophic disruption of the target into individual fragments, is estimated. For organic glass, the value of _k is found to be 4 × 10⁴J/kg. The mass of the largest (central) fragment accounts for 27 to 33% of the overall mass ejected from the impact crater. The use of the parameter ₃= _p / _p v ² ₀gives the best fit to the observational data for the masses released from the impact and chop craters.     

On the Shape of an Impact Crater at High-Speed Impacts

This paper presents the results of an experimental study on the geometric parameters of craters that originated at the impact interaction of polyethylene projectiles with a massive organic-glass target. The impactor speed ranged from 2.7 to 6.28 km/s. The shapes of the resulting craters are determined. Using statistical analysis and scaling theory, we obtained the dependence of the diameter and depth of the crater on defining parameters. The critical impact energy resulting in the catastrophic breakup of the target is estimated.     

Automated construction of the boundaries of basin geosystems for the Volga Federal District

Using the Volga (Privolzhskii) Federal District as an example, we offer the solution of such a currently central scientific and methodological problem as automated identification of the boundaries of basin geosystems under different landscape and geomorphological conditions in terms of multiresolution digital elevation models. The main stages of work are described, namely the development of the digital elevation model, its hydrological adjustment, identification of the boundaries of basin geosystems, and validity assessment of results obtained. The technique has been developed for constructing a hydrologically valid digital elevation model with the purpose of identifying the boundaries of basin geosystems.     

Cartographic model of river basins of European Russia

An analysis made of the worldwide existing geoinformation systems (HydroSHEDS, CCM, Ecrins, WBD, etc.) suggests that there are as yet no models of adequate quality for the basin boundaries of small rivers in the European part of Russia. For the territory of the European part of Russia with a total area of more than 4 mln. km2 the GIS technology tools were used to construct the electron vector map of river basins and their interbasin spaces. The map thus obtained displays the basins of first-order rivers for a given level of generalization (sc 1:1 000 000). The GMTED2010 model was used as the digital elevation model. A total of 63 553 basin geosystems were identified on the map, averaging 68 km2 in area. Accuracy verification of identifying the basin boundaries showed a good agreement of areal and geometric characteristics of the method used with expert approach. In test areas, the men difference of the indicators of the area of the basins identified automatically and by use of the expert approach made up 3.6%. For areas with weakly dissected lowland topography this error does not exceed 5% while it is about 2% in areas with relatively dissected elevated topography. The basin geosystems thus identified are operational-territorial units with respect to which the geospatial data base is generated to characterize the natural-resource potential of the European territory of Russia. An example is provided for the generation of the geospatial database containing hydrological information covering 1763 hydrological stations collecting streamflow data.     

Spatio-Temporal Assessment of Gully Erosion in the Zone of Intensive Agriculture in the European Part of Russia

Using the method of mapping by high resolution satellite imagery mapping, a study was made of the key areas which are located in the southern part of the forest, forest-steppe and steppe zones of Tatarstan and of Orenburg, Saratov and Voronezh oblasts. Two key indicators were determined: the gully length density and gully head density within the basins; results of the investigation were used in compiling respective maps in vector format. It is established that the density of the gully length in the basins varies over the range from 0 to 0.5 km/km² (from the absence of gullies to strong gully erosion), and the density of gully heads from 0 to 3 units/km². The slope type of gullies is dominant in all basins (about 80%), while the coastal and bottom types have approximately the same proportion (14 and 10%, respectively). Using methods of mathematical statistics we determined a high directly proportional dependence of the indicators of the contemporary gully network on the level of ploughness of the basins and the mean annual precipitation amount, and an indirectly proportional dependence on the level of sodding. An abrupt reduction in gullying indicators was determined. It was found that among the chief reasons behind an abrupt reduction in the gullies to date is a decrease of the rate of agricultural development, with an additional factor, namely, a dramatic decrease in surface runoff down the arable slopes during spring snowmelt caused by climate warming. It is concluded that that a significant part of the gully forms in the study area is currently inactive and massively passes into the balka stage.     

An Investigation of the Reliability of HF Acid Mixtures in the Bomb Digestion of Silicate Rocks for the Determination of Trace Elements by ICP‐MS

The influence of the mixtures HF‐HNO₃ and HF‐NH₄F‐HNO₃ in bomb digestion for trace element determination from different rock types was studied using ICP‐MS. It is shown that the HF concentration, not the ratio of reagents in the decomposing mixture, controls the digestion process of a rock. Data for Zr in the granite G‐2 as a function of HF concentration gave the same results as reaction mixtures of various compositions. A complete digestion in 50‐mg sample bombs was achieved by 1.0 ml of HF alone, or with a mixture of other acids at a HF concentration of at least 35% m/m at 196 °C over 18 h. The results of the analysis of basalts BCR‐1, BIR‐1, mica schist SDC‐1, shale SBC‐1, granites G‐2, SG‐1A, garnet‐biotite plagiogneiss GBPg‐1, rhyolite RGM‐1, granodiorite GSP‐1, trachyandesite MTA‐1 and rhyolite MRh‐1 are given and compared against available data. The reproducibility of the element determinations by ICP‐MS and XRF as an independent non‐destructive analysis for a quality check in the range of concentrations typical for routine rock samples is given.     

Types of spectra of ion flux fluctuations in the solar wind and magnetosheath at the interface between inertial and dissipative ranges

This paper considers the features of turbulent characteristics of ion flux variations in the solar wind and magnetosheath at the scale of 0.01–10 Hz based on measurements on the BMSW plasma spectrometer (Plasma-F experiment) mounted on the Spektr-R satellite. A variability of types of fluctuation frequency spectra is shown. Fluctuation spectra with certain features in the transition region from the inertial to the dissipative range are selected (a sharp knee in the fluctuation spectrum, plateau and peak in the knee, and a nonlinear spectrum bend at high frequencies). The degree of difference between the observed spectra and the spectra characteristic of the developed isotropic turbulence in the Kolmogorov model is determined. The probability of observation of the spectra of certain types is estimated. The features of fluctuation spectra in the solar wind and magnetosheath are compared for each type of spectra.