Geological evolution and petroleum systems in the North Caspian Region

The structure and formation evolution of the principal North Caspian zones (North Caspian Basin, Karakul-Smushkovskii Foredeep, South Emba Foredeep, Karpinsky Range Fold Zone, Mangyshlak-Central Ustyurt Fold Zone, etc.) are discussed. Drilling data and seismic profiles were utilized in the study, and an analysis of hydrocarbon systems has been performed.     

Measurements of thermal conductivity and specific heat in volcanogenic rocks

A laboratory installation has been developed together with a technique for determining thermo-physical properties (thermal conductivity and specific heat) in cylindrical rock specimens. The technique is based on iTOUGH2-EOS3 inversion modeling using temperature measurements inside specimens as a result of their short-term heating and subsequent return to the initial temperature. We estimated the thermal conductivity and specific heat for a collection of volcanogenic petrotypes that reflect the rocks that compose the Rogozhnikovskii volcanogenic oil reservoir (29 specimens). The average thermal conductivity of the dry rocks is 1.47 W/m °C and the average specific heat is 754 kJ/kg °C; the reproducibility of this estimation is 2.2% for thermal conductivity and 0.7% for specific heat.     

Pressure effects on the reduced partition function ratio for hydrogen isotopes in water

We have developed a simple, yet accurate theoretical method for calculating the reduced isotope partition function ratio (RIPFR) for hydrogen of water at elevated pressures. This approach requires only accurate equations of state (EOS) for pure isotopic end-members (H₂O and D₂O), which are available in the literature. The effect of pressure or density on the RIPFR of water was calculated relative to that of ideal-gas water at infinitely low pressure for the temperature range from 0 to 527 °C. For gaseous and low-pressure (ca. ?15 MPa) supercritical phases of water, the RIPFR increases slightly (1-1.3‰) with pressure or density in a fashion similar to those of many other geologic materials. However, in liquid and high-pressure (>20 MPa) supercritical phases, the RIPFR of water decreases (0.5-6‰) with increasing pressure (or density) to 100 MPa. This rather unique phenomenon is ascribed to the inverse molar volume isotope effects (MVIE) of liquid and high-density supercritical waters, V (D₂O) > V (H₂O), while other substances including minerals show the normal MVIE. These theoretical predictions were experimentally confirmed by Horita et al. [Horita, J., Cole, D.R., Polyakov, V.B., Driesner, T., 2002. Experimental and theoretical study of pressure effects on hydrogen isotope fractionation in the system brucite-water at elevated temperatures. Geochim. Cosmochim. Acta66, 3769 - 3788.] for the system brucite-water. Although the P-T ranges for the EOS of normal and heavy waters are rather limited, our modeling indicates that the RIPFR of water continues to decrease with pressure above 100 MPa. The method developed here can be applied to any other geologic fluids, if accurate EOS for their isotopic end-members is available. These results have important implications for the interpretation of high-pressure isotopic partitioning in the Earth, the outer planets, and their moons.     

Isotope composition of groundwater in the Azov-Kuban and Eastern Pre-Caucasian artesian basins

Studying results of the groundwater isotope composition in the Neogene-Quaternary and Mesozoic sediments of the Azov-Kuban and Eastern Pre-Caucasian artesian basins have shown in the Pliocene sediments a rather wide distribution of ??relict?? groundwater, formed because of melting of the Late Pleistocene Caucasian glaciers, as well as of groundwater formed due to its mixing with the meteogenic waters of the subsequent Holocene infiltration cycles. Also, the areas are revealed in the Lower-Miocene sediments where meteogenic waters are mixed with sedimentation waters, while in the Mesozoic formations??the areas where into the sedimentation waters wedge-shaped meteogenic waters of Pleistocene and Holocene infiltration periods are intruded.     

Origin of the Permian-Triassic komatiites,northwestern Vietnam

Abstract Rare examples of Phanerozoic komatiites are found in the Song Da zone, NW Vietnam. These komatiites were erupted through continental crust and may belong to the SE extension of the Permo-Triassic Emeishan volcanic province located in SW China. They provide a good opportunity to study the source characteristics of starting plume magmas in a continental flood basalt province. Erupted on late-Permian carbonate rocks, the komatiitic rocks are interbedded with low-Ti olivine basalts. Basaltic komatiites display pyroxene spinifex textures, while more magnesian rocks (MgO up to 32 wt.%) are porphyritic, containing a single, cognate population of euhedral to elongated olivine phenocrysts with Fo up to 93.0%. This suggests a highly magnesian parental magma with 22–23 wt.% MgO. In terms of major and minor elements, the komatiites are similar to the ca. 89 Ma old Gorgona Island komatiites of Colombia. The Song Da komatiites are also strongly light-rare-earth-element- (LREE) depleted (Ce_N/Yb_N 0.30–0.62) and have unfractionated heavy rare earth element (HREE) patterns. The komatiites have high Os concentrations (up to 7.0 ppb), low but variable Re/Os ratios, and define an isochron with an age of 270±21 Ma, and an initial ¹⁸⁸Os/¹⁸⁷Os ratio of 0.12506± 0.00041 (_Os=+0.02±0.40). The Os isotopic systematics of the komatiites show no effects of crustal contamination. In contrast, their initial _Nd values range from +3 to +8, reflecting varying but generally small degrees of contamination with Proterozoic sialic basement material. Associated low-Ti basalts have low initial _Nd values (–0.8 to –7.5), high initial _Os values (15), flat or LREE-enriched REE patterns, and Nb-Ta depletion. These characteristics are also attributed to variable extents of crustal contamination.Editorial responsibility: T.L. Grove     

Regular intergrowths of minerals in pegmatites from the Il’meny mountains

This paper summarizes the data on oriented intergrowths of minerals in pegmatites of the Il’meny Mountains. Two-feldspar, two-mica, biotite-amphibole, biotite-pyroxene, and pyroxene-amphibole intergrowths have been revealed in syenitic and miaskitic pegmatites. The orientation of exsolution products has been studied in sunstone (aventurine) and moonstone feldspars, nepheline, and cancrinite. Corundum-biotite-feldspar and two-mica intergrowths and exsolution lamellae occur in stellate corundum from corundum-feldspar veins. Syntactic intergrowths of various amphiboles and chlorites have been detected in pegmatoid ultramafic rocks. Regular quartz-feldspar (graphic) and two-feldspar intergrowths are typical of granitic pegmatites. Two-mica, columbite-samarskite, columbite-ilmenorutile, zircon-xenotime, cassiterite-ilmenorutile, cassiterite-ixiolite, cassiterite-tantalite, tantalite-stibiotantalite, fergusonite-columbite, pyrochlore-fergusonite, and beryl-cordierite intergrowths have been found in granitic pegmatites as well. New intergrowth laws have been established for many pairs of minerals.     

Accumulation Properties of Major and Trace Elements of the Subcolloidal Fraction of Bottom Sediments in the Marginal Filter of the Razdolnaya River (Amur Bay,Sea of Japan) under the Influence of Increased Runoff

Oceanology - The study reveals the distribution of contents of major (Si, Al, Fe, Mn) and trace elements (Ga, V, W, Th, Mo, U, Be, Y, Cd), Сorg, and clay minerals in the subcolloidal fraction...     

Interannual and seasonal variations in ozone in different atmospheric layers over St. Petersburg based on observational data and numerical modeling

This paper analyzes atmospheric ozone variability at different altitudes over St. Petersburg for the period 2009–2014 on the basis of surface observations at the Peterhof station, satellite measurements with an SBUV instrument, and numerical simulations. Simulation data on temperature, wind velocity, humidity, and surface pressure are taken from the MERRA reanalysis database. Based on ozone measurements, numerical modeling, and reanalysis data, characteristics of ozone seasonal and interannual changes are identified; the role of photochemical and dynamic factors in ozone variations is estimated.