Compositional,structural, and geodynamic controls of the evolution of inter- and intramontane basins of the Tien Shan

The crustal orogeny which formed the present-day Tien Shan results from the complex interaction between two independent processes. The first is the lateral (horizontal) compression related to the collision between the Indian and Eurasian Plates. The second is the rearrangement and flow of crustal material at different levels of the lithosphere beneath the mountain belt. Two broad morphologic and genetic types of mountain basins (intramontane and intermontane/foreland) are proposed as indicators of specific geodynamic factors controlling the topographic relief of the orogenic belt. The first-type basins, having the upper crustal roots, reflect mainly the N–S crustal compression and correspond to simple (elementary) longitudinal folds with basement involvement. The second type basins developed mostly in response to deep processes in the upper mantle and lower crust.     

Multi-Wavelength Synchrotron Radiation XRF Determination of U and Th in Sedimentary Cores from Lake Baikal

A new technique for the determination of uranium and thorium in lacustrine sediments is based on non-destructive synchrotron radiation X-ray fluorescence analysis (SR-XRF) of sediment samples using monochromatic beams of different energies as excitation sources, with the recording and subsequent iterative processing of the X-ray fluorescence spectra. The technique has a multielement capability and enables fast, simultaneous analysis of a few tens of elements. The proposed SR-XRF technique was tested against INAA and ICP-MS methods and showed a number of advantages with a generally good correlation of results by the three methods. Uranium and Th profiles have been measured at a time resolution of 2 kyr in a drill core (BDP-96) from Lake Baikal bottom sediments deposited between 780 and 40 kyr B P. During this time span, peaks in the U and U/Th concentration marked warm climates. Oscillations of U and U/Th in Baikal bottom sediments during the Brunhes chron reflect climate-induced global change in the volume of polar ice, controlled by long-term cyclicity of the Earths orbital parameters. The response of these warm periods is similar to that observed earlier in shorter cores that span the two last interglacials (220-0 kyr BP).     

The Disastrous Water—Stone Flow in the Kyngarga River (Republic of Buryatia) on June 27–29, 2014, according to Seismological Data

Doklady Earth Sciences - This paper reports on the results of the seismic studies on the disastrous water-stone flow passing down the Kyngarga River (Republic of Buryatia) on June 27–29,...     

Ions of Organic Carboxylic Acids (Formic,Acetic, and Oxalic) in the Snow Cover of Permafrost Landscapes of Boreal Eastern Siberia

The distribution of ions of organic carboxylic acids (formic, acetic, and oxalic) was investigated in the snowpack of permafrost landscapes of the boreal zone of Eastern Siberia. The contents of formate-, acetate-, and oxalate-ions were determined in permafrost landscapes of different zones of latitudinal and mountain- belt types. The maximum contents of organic carboxylic acid ions were observed in the snow cover of middle-taiga landscapes. The input rate of the ions into the snow cover of middle-taiga and mountain landscapes is controlled by altitudinal zonation and correlates with the total mass of plant organisms, which are the main source of organic carboxylic acids in the atmosphere. The obtained data suggest that organic carboxyl acid ions were supplied mainly by the atmosphere (74–90%), whereas the contribution of soil respiration was minor. The upward migration of organic carboxylic acid ions from the substrate to the snow cover depends on soil and snow temperature. Cooling of the soil surface below–5°C results in a considerable decrease in the migration of organic carboxylic acid ions from soil to snow.     

Comparison of Synchrotron Radiation X-Ray Fluorescence with Conventional Techniques for the Analysis of Sedimentary Samples

A comparison is made of elemental analyses of sediment samples (lake bottom sediments and sediments from the petroliferous Bazhenovka Formation) by five competitive methods (synchrotron radiation X-ray fluorescence (SR-XRF), INAA, ICP-MS, AAS and traditional XRF). The object of this study was to identify the most suitable analytical techniques for applications in sedimentary geochemistry. Advantages and shortcomings of the five techniques were considered with respect to applications related to studies of palaeo-climate changes recorded in sedimentary cores from Lake Baikal and the geochemical stratigraphy of the Bazhenovka Formation, which is rich in organic material. We have concluded that SR-XRF was the best technique for producing extensive analytical data series, from the point of view of its speed, ease of application, cost, non-destructive nature and sensitivity, which allowed for the simultaneous determination of more than twenty elements of geochemical interest in small samples of sediments. An additional benefit of the method was demonstrated when used for the independent certification of geological reference materials. International reference samples BIL-1 and SDO-1 were certified by means of this method without use of reference materials. Analyses were based on the physics of the theory of energy transport.     

Regular Variations of Intensity of the Westward Auroral Electrojet according to the Geomagnetic <Emphasis Type="Italic">AL</Emphasis> Index

Diurnal and seasonal variations of the geomagnetic AL index are studied. It is found in disturbed days that the mode of AL diurnal variation depends on the angle between the Sun–Earth line prolongation in the direction towards the magnetotail and the plane of geomagnetic equator; on quiet days, AL depends on the angle of attack between the geomagnetic axis and the Earth–Sun line. Seasonal AL variations are characterized by annual variations with summer maximum and semiannual variations with equinoctial maxima. It is shown that the semiannual AL variations can be described by a simplified model of plasma convection in the magnetotail based on a plasma electron cooling mechanism.     

Geomagnetic activity as a reflection of processes in the magnetospheric tail: 1. The source of diurnal and semiannual variations in geomagnetic activity

Diurnal and semiannual variations in geomagnetic activity are considered. We prove that there exists an inner magnetospheric source of magnetic activity, which depends on the angle φ between the planes of the magnetotail plasma sheet and the geomagnetic equator. It is shown that diurnal and semiannual variations in magnetic activity result from changes in the value of this angle.     

Geochemistry of cryoconite and soils in the Central Caucasus region and its environmental implications

Climate change and deglaciation are active processes in current changing environments.In the Central Caucasus region rapid degradation of glaciers is caused oft...     

Robotic optical telescopes global network MASTER II. Equipment, structure, algorithms

Presented paper describes the basic principles and features of the implementation of a robotic network of optical telescopes MASTER, designed to study the prompt (simultaneous with gamma radiation) optical emission of gamma-ray bursts and to perform the sky survey to detect unknown objects and transient phenomena. With joint efforts of Sternberg astronomical institute, High altitude astronomical station of the Pulkovo observatory, Ural state university, Irkutsk state university, Blagoveshchensk pedagogical university, the robotic telescopes MASTER?II near Kislovodsk, Yekaterinburg, Irkutsk and Blagoveshchensk were installed and tested. The network spread over the longitudes is greater than 6?h. A further expansion of the network is considered.     

Exploring local N-body simulations of Saturn's rings

The dynamical behavior of low and moderately high optical depth regions of Saturn's ring system of discrete, mutually gravitating, and inelastically colliding particles is studied by simplified local N-body simulations in Hill's linearized equations context. The focus is on a statistical analysis of time-evolution of fine-scale structures seen in the simulations and the comparison between theoretical predictions and computer experiments. Prospects for the Cassini spacecraft mission are briefly summarized.