The Nature and Age of Plagioclasites in the Ultrabasic Rai-Iz Massif (Polar Urals)

Corundum-containing and corundum-free plagioclasites localized in chromite-bearing ultramafites of the Rai-Iz Massif were explored for the composition and age. The composition of rock-forming minerals was studied, and the geochemical characteristics of the rocks were ascertained. The isotope age of plagioclasites determined by zircons using the U–Pb mode with a SHRIMP II device was equal to 398 ± 3 Ma. The age found conformed to the boundary on most of the Rai-Iz Massif took place against the background of a starting powerful collision, which caused the formation of the chromium mineralization of a high-chromic type, as well as the separation of a series of essentially plagioclase rocks of ruby mineralization at the discharge zones of the vein series.     

The 2006 (Мw 8.3) and 2007 (Мw 8.1) Simushir Earthquakes and the 2011 Tohoku Megaearthquake (Мw 9.0): Tectonic Stresses and Development of the Seismic Process

The peculiarities of catastrophic earthquakes that occurred in the Northwest Pacific region on January 13, 2007, and January 15, 2007, east of the Kuril Islands and the Tohoku megaearthquake of March 11, 2011, east of Japan are considered and analyzed. It is revealed that these earthquakes, apart from the fact that they occurred in the transition zone from the Pacific to island arcs and the Eurasian continent, have common features and similar characteristics. The seismotectonic slip in the source of the chronologically first event, the 2006 Kuril earthquake, was a gentle thrust, while that of the second event of January 13, 2007, was a downthrow beneath the Kuril deep trench.     

Faults and Source Parameters of Earthquakes in the Baikal Rift Zone: Dip Angles of Fault Planes

Analysis of gentle, intermediate, and steep dip angles of fault planes in earthquake sources of the Baikal region is carried out with the slips in seismic sources being taken into account. The areas where normal faulting slips at steep, intermediate, and gentle angles took place are distinguished, and this can be interpreted as transformation of a steep dip to gentle one. It is found that the increase in energy class is accompanied by the number of earthquakes with steep dip angles, whereas the proportion of earthquakes with intermediate angles decreases, and the fraction of earthquakes with gentle angles remains quasi-stable and small.     

Aerosols in the Near-Water Surface Layer of the Caspian Sea

The first data on the concentrations, fluxes, and mineral and chemical compositions of aerosols from the near-water surface layer of the Caspian Sea are presented. It is shown that the aerosol fluxes onto the sea surface are comparable to the fluxes of a lithogenic substance in a water column. The mineral and chemical compositions of aerosols depend on the carrying air masses that pass through different regions. The coefficients of enrichment of aerosols with chemical elements relative to the upper lithosphere and their correlation relationships are studied.

     

The Stress–Strain State of Recent Structures in the Northeastern Sector of the Russian Arctic Region

Doklady Earth Sciences - Complex research to determine the stress–strain state of the Earth’s crust and the types of seismotectonic destruction for the northeastern sector of the...     

Ya.B. Zeldovich and Foundation of the Accretion Theory

This brief review is dedicated to academician Yakov Borisovich Zeldovich, the science of his epoch and the creation of modern accretion theory.     

On the Final Gravitational Wave Burst from Binary Black Holes Mergers

We use perturbation theory in the strong-field regime to study the inspiral-to-plunge transition of a test particle into a Kerr black hole. We found a smooth transition, without burst, and with lower energy and angular momentum radiated in gravitational waves with respect to previous treatments in the literature. Besides their theoretical interest, our results are relevant for the waveform templates of binary black hole mergers used for gravitational waves detection which are constructed on the basis of a inspiral-to-plunge transition with a high energetic burst.     

Equilibrium Configurations of Rotating White Dwarfs at Finite Temperatures

In this work, cold and hot, static and rotating white dwarf stars are investigated within the framework of classical physics, employing the Chandrasekhar equation of state. The main parameters of white dwarfs such as the central density, pressure, total mass and radius are calculated fulfilling the stability criteria for hot rotating stars. To construct rotating configurations the Hartle approach is involved. It is shown that the effects of finite temperatures become crucial in low-mass white dwarfs, whereas rotation is relevant in all mass range. The simultaneous accounting for temperature and rotation is critical in the calculation of the radii of white dwarfs. The results obtained in this work can be applied to explain a variety of observational data for white dwarfs from the Sloan Digital Sky Survey Data Releases.     

A Polychronous Locality of Megafauna on the Northwestern Coast of Lake Baikal

Doklady Earth Sciences - Based on geochronological data, it is shown that the formation of sediments of a 50–80 m terrace of Lake Baikal occurred during the Middle Pleistocene and its top...     

First Data on the Isotopic Age of Zircons from Rocks of the Roseta Ultramafic Massif,Southern Margin of the São Francisco Craton (Brazil)

Doklady Earth Sciences - The results of isotope U–Pb dating of zircons from lherzolite and vein olivine orthopyroxenite composing the Roseta ultramafic massif are presented. The zircons...