Comparison of Different Estimates of the Accuracy of Forecasts of the Earth’s Rotation Parameters

Astronomy Reports - Improvement of the prediction accuracy of the Earth’s rotation parameters (ERP) is one of the main problems of applied astrometry. In order to solve this problem, various...     

Features of the Influence of Weather Conditions on the Deformation Processes of the Upper Layer of the Earth’s Crust

Doklady Earth Sciences - The influence of the temperature and moisture content of the near-surface soil layer on variations of the barodeformation interaction of the boundary layer of the...     

Effect of Atmospheric Pressure on the Deformation of the Earth’s Crust

Doklady Earth Sciences - A method for estimating the contribution of atmospheric pressure variations to the deformation of the upper layer of the Earth’s crust using synchronous data from...     

Genesis of the mineral groundwaters of the Razdol’nenskii occurrence in Primorye

Original isotopic and chemical data are reported on the groundwater and gases from the unique occurrence of mineral water in the coastal zone of southern Primorye. Results of the δ¹⁸O and δ²H analysis of the underground and surface water of the area integrated with their δ¹³C composition made it possible to solve the problem of the genesis and evolution of groundwater and gases in the coastal part of the Sea of Japan. It was established that meteoric waters penetrate into the Mesozoic terrigenous rocks and changed their chemical composition under the influence of transformation of organic matter from the host rocks. CO₂ released owing to reactions provides multiple enrichment of the water in HCO₃ and stimulates Na influx via dissolution of aluminosilicates.     

Equation of state of magnesite for the conditions of the Earth’s lower mantle

A semiempirical equation of state was derived for magnesite under the thermodynamic conditions of the Earth’s mantle. Within experimental uncertainties, it is consistent with thermochemical, ultrasonic, X-ray, and shock-wave data at temperatures from 15 K to the melting point and pressures of up to 100–130 GPa. The following values were recommended for the isothermal bulk modulus and its pressure derivative: K _T = 111.71 GPa and K′ = 4.08. Thermodynamic analysis showed that magnesite does not decompose to periclase and CO₂ under the thermodynamic conditions of the Earth’s lower mantle and outer core.     

Typochemical features of the rare-earth component of monazites from the Ilmen’ reserve

By means of X-ray fluorescence with synchroton radiation (XRF-SR), the contents of all 14 rare-earth elements (REEs) and that of Y were determined in 12 monazite samples from different veins in the Ilmen’ Reserve (South Urals). It was found that, in anphibole-micaceous-carbonate mineralized zones within metabasites, monazites were pronouncedly depleted in middle and, especially, in heavy rare-earth elements (HREEs) (from 0.25% and below for Sm, 0.08% or below for Gd, 0.03% for Dy, 0.01% for Er and Tm, below 0.005% for Yb, trace amounts of other odd HREEs, at a Y content of 0.1% or below). Monazites from the veins of granitic pegmatites were characterized by vastly decreased La contents (4–8 compared to 11–13% for the group above), at high values for Pr (to 3%), Nd (to 8%), Sm (to 1.3%), Gd (to 1.1%), Dy (to 0.9%), Er (to 0.2%), Yb (to 0.05%), and Y (from 0.2 to 1.7%). Here, the values for odd REEs are also quite high compared to the group above (to 0.2% for Tb, to 0.08% for Ho, and to 0.1% for Tm).

     

Tectonostratigraphy of the Mesozoic complexes of the northwestern part of the Koryak Highland,Ust’ Belaya Mountains

New data on the structure, age, and composition of the tectonostratigraphic complexes of the western part of the Koryak Highland are presented. The conclusions on the sedimentation conditions are drawn and primary relations are interpreted for most complexes. New Kimmeridgian–Tithonian and Berriasian assemblages of radiolarians are established. Campanian radiolarians are found for the first time in the region.     

Estimation of the stress state of the Earth’s crust and the upper mantle in the area of the Southern Kuril Islands

The catastrophic Shikotan earthquake of October 4 (5), 1994, occurred in the Pacific Ocean. Its focus was located 80 km eastward of Shikotan Island. The stress state of the Earth’s crust in this area was estimated by the method of the cataclastic analysis of the whole range of the earthquake mechanisms. The performed reconstruction of the parameters of the current stress state of the Earth’s crust and the upper mantle in the area of the Southern Kuril Islands made it possible to establish that this area is characterized, on the one hand, by the presence of extensive areas of steady behavior of the stress tensor parameters and, on the other hand, by the presence of local sections of anomalously fast changes in these parameters.     

Chemical transformation of the runoff of dissolved matters in the mouth areas of the Onega and Mezen’ rivers

Natural observations were analyzed to study the distribution of dissolved species of major and trace elements in the Onega and Mezen’ mouth areas and the tendencies in the chemical transformations of the is continental runoff in the river mouths of the White Sea drainage system. It is shown that the migration of major ions and dissolved species of Li, Rb, Cs, Sr, B, F and Mo is consistent with a conservative behavior and is controlled by hydrodynamic processes. The amounts of uranium and barium additionally supplying in the Mezen’ mouth exceed those removed with a continental runoff, whereas the Onega, Severnaya Dvina, and other rivers of the White Sea drainage system are characterized by the conservative behavior of uranium, while barium desorption from particulate matter reaches no more than 33% of its content in the riverine waters. The growth of concentrations of these elements in the Mezen’ mouth is caused by the long-term interaction of solid matters of the continental runoff with saline waters in the tide-affected estuary. 28–59, 12–63, 25–67 and 20–63% of concentrations of iron, aluminum, lanthanum, and cerium are removed from the riverine waters in the mouth areas of all studied rivers of the White Sea drainage system mainly owing to the coagulation and flocculation of organic and organomineral colloids. The distribution of dissolved species of mineral phosphorus and silicon in the Mezen’ mouth is presumably controlled by the remineralization of the organic matter in the bottom sediments, which due to the hydrological features of estuary are regularly stirred up and interact with vertically mixing water sequence. Up to 20–46% of dissolved phosphates and 3–22% of silicon are removed from the continental runoff during vegetation period in the mouths of the Onega, Severnaya Dvina, and other rivers of the White Sea drainage system mainly owing to their biological consumption.     

Determination of the Parameters of the Earth’s Gravitational Field from Gradiometric Measurements

Astronomy Reports - The paper discusses the goals and objectives of the GOCE project, the measurement information and the data processing strategy used in determining the parameters of the...     

Intrayear irregularities of the Earth’s rotation

The methods of celestial mechanics can be used to construct a mathematical model for the perturbed rotational motions of the deformable Earth that can adequately describe the astrometric measurements of the International Earth Rotation Service (IERS). This model describes the gravitational and tidal influences of the Sun and Moon. Fine resonant interactions of long-period zonal tides (annual, semiannual, monthly, and biweekly) with the diurnal and semidiurnal tides are revealed. These interactions can be reliably confirmed via a spectral analysis of the IERS data. Numerical modeling of tidal irregularities of the Earth’s axial rotation was carried out, focusing on the analysis and forecasting of variations of the day length occurring within short time intervals of a year or shorter (intrayear variations).     

Influence of the Growth of Earth’s Solid Core on the Effective Geodynamo

Doklady Earth Sciences - A model of the Earth’s cooling, which describes the formation of a solid core, is considered. Its formation enhances the convection due to additional energy sources...     

Isotope-geochemical constraints on the formation of the early Earth’ crust

Analysis of isotope-geochemical data obtained for the early crustal complexes of the Earth provided constraints on the formation time, scales of development, and geochemical features of protocrust. Most informative were isotope-geochemical and geochemical data on the oldest zircons with ages up to 4.4 Ga, short-lived ¹⁴⁶Sm/¹⁴²Nd isotope system, and lead isotope composition of the oldest rocks of Greenland. The presence of positive ¹⁴²Nd anomaly in the rocks of West Greenland and negative anomaly in the amphibolites of the oldest Nuvvuagittuq greenstone belt of the Superior province (O’Neil et al., 2008) indicates the early differentiation of the Earth material into depleted mantle and enriched (basaltic) crust (Caro et al., 2006; Benett et al., 2007a, b; O’Neil et al., 2008). Pb-Pb isotopic systematics of the oldest crustal rocks from West Greenland and Labrador testifies that high μ enriched crust (²³⁸U/²⁰⁴Pb = 10.9) of basaltic composition already existed 3.9 Ga ago (Kamber et al., 2003). Based on isotope-geochemical and geochemical features of the oldest zircons in the Late Archean greenstone belts of the Yilgarn block (Western Australia), the crust of intermediate-felsic composition and water on the Earth’s surface already existed 4.4 Ga ago (Wilde et al., 2001).     

Carbonate equilibrium in the water of the Razdol’naya River

The paper suggests an accurate approach to studying carbonate equilibrium in the water of the Razdol’naya River. The approach involves measuring pH by Pitzer’s scale, using a cell without liquid junction; measuring the total alkalinity by Bruevich’s technique; and using apparent constants of carbonate equilibrium with regard for the organic alkalinity. The Pitzer technique was employed to calculate the apparent constants of carbonate equilibrium in solution that models the riverine water: Ca(HCO₃)₂–NaCl–H₂O within the range of alkalinity of 0–0.005 mol/kg and temperatures of 0–25°C. Carbonate equilibrium in the water of the Razdol’naya River was sampled for studying at eight sites during all four seasons. Although the contents of biogenic compounds in the water are high, they can merely insignificantly affect the acid–base equilibrium, which is controlled in the riverine water by carbonate equilibrium and the concentrations of humic substances, which play the greater role, the greater the discharge of the river. In addition to the production and destruction of organic matter, carbonate equilibrium in the river is also affected by the supply of humic substances with soil waters and total alkalinity with groundwaters. The fluxes of alkalinity and humic substances annually brought by the Razdol’naya River to Amur Bay are evaluated at 1.33 × 10⁹ mol and 9.9 × 10⁶ kgC, respectively. The carbon dioxide export with the Razdol’naya River is equal to the alkalinity flux and does not depend on the weathering mechanisms.     

Lateral protrusions in the structure of the Earth’s lithosphere

The factual material and modeling results concerning the geology of specific structural elements defined as lateral protrusions, or flowing layers, are considered. The formation of such structural elements is a fundamental phenomenon that controls many features of the structural evolution and geodynamics of platform basement and foldbelts. A lateral protrusion, or flowing layer, is a spatially constrained, nearly horizontal geological body with attributes of 3D tectonic flow (rheid deformation) and lateral transport of rock masses. Flowing layers are large lateral protrusions that play important role in the structure of the continental and oceanic lithosphere. They embody the internal mobility of huge rock bodies and confirm the possibility of their lateral redistribution at different depths of the continental lithosphere. The lateral displacement of rocks within such assemblies may occur in the regime of cold deformation, heating, metamorphism, and ductile flow of rocks under subsolidus conditions or in the process of their partial melting.