Specific Compositional Features of Sediments from the Haakon Mosby Mud Volcano,Southwestern Barents Sea

The submarine Haakon Mosby mud volcano was studied in detail during several cruises, resulting in the collection of an abundant and diverse lithological material. Comprehensive field and laboratory studies made it possible to identify different types of sediments with specific granulometric and pelite fraction (<0.005 mm) compositions, as well as the regularity of their spatial distribution relative to various morphostructural zones of the mud volcano.     

Magmatic Evolution of Changbaishan Tianchi Volcano,China–North Korea: Evidence from Mineral-Hosted Melt and Fluid Inclusions

Data on mineral-hosted melt, fluid, and crystalline inclusions were used to study the composition and evolution of melts that produced rocks of Changbaishan Tianchi volcano, China–North Korea, and estimate their crystallization parameters. The melts crystallized within broad ranges of temperature (1220–700°C) and pressure (3100–1000 bar), at a drastic change in the redox potential: Δ log \(f_{O_2}\) from NNO + 0.92 to +1.42 for the basalt melts, NNO –1.61 to –2.09 for the trachybasaltic andesite melts, NNO –2.63 to –1.89 for the comendite melts, and NNO –1.55 to –3.15 for the pantellerite melts. The paper reports estimates of the compositions of melts that produced the continuous rock series from trachybasalt to comendite and pantellerite. In terms of trace-element concentrations, all of the mafic melts are comparable with OIB magmas. The silicic melts are strongly enriched in trace elements and REE. The most strongly enriched melts contain concentrations of certain elements almost as high as in ores of these elements. The paper reports data on H2O concentrations in melts of different composition. It is demonstrated that the variations in the H₂O concentrations were controlled by magma degassing. Data are reported on the Sr and Nd composition of the rocks. The deviations in the Sr isotopic composition are proportional to the ⁸⁷Sr/⁸⁶Sr ratio and could be produced in a melt with a high enough ⁸⁷Sr/⁸⁶Sr ratio during a geologically fairly brief time period. The evolution of melts that produced rocks of the volcano was controlled by crystallization differentiation of the parental basalt magmas at insignificant involvement of melt mixing and liquid immiscibility of silicate and sulfide melts. The alkaline salic rocks were generated in shallow-sitting (13–3.5 km) magmatic chambers in which the melts underwent profound differentiation that gave rise to pantellerites and comendites strongly enriched in trace elements (Th, Nb, Ta, Zr, and REE). Data on the composition of the magmas and parameters of their derivation are used to develop a generalized petrologic–geodynamic model for the origin of Changbaishan Tianchi volcano.     

Hazards and Risks of Recreational Water Use: Vectors of International Studies. Effects of Recreation on Ecosystems and Biota

Water Resources - English-language publications on the assessment of hazards and risks in recreation water use are reviewed. The main themes and results of foreign studies into the effect of...     

Using the optical and radar satellite images for the analysis of ecological conditions in the marine environment

Considered are the possibilities for detecting the zones of ecological problems of marine environment using the ocean color sensors data and the radar images. Presented are the peculiarities of satellite data interpretation and the experimental results indicating the spatial and temporal distribution of biogenic slicks and chlorophyll-a concentration as the indicators of ecological conditions in the marine environment. Proposed is the multiparameter correlation graph displaying the relationship between the ecological factors significant for studying the anthropogenic eutrophication.     

Scenarios of nonlinear wave transformation in the coastal zone

On the basis of field experiments and numerical modeling, we show that coastal zones are classifiable according to manifestations of wind wave nonlinearity, which herein is recognized as periodic energy exchange between the first and second nonlinear wave harmonics depending on the average bottom slope and the Iribarren and Ursell numbers. The results offer a basis for developing vulnerability criteria for the coastal zone taking into account its nonlinear dynamics.     

Chemical composition of melts of the Early Eocene volcanic center at Cape Khairyuzova,western Kamchatka: Evidence from inclusions in minerals

Original authors’ data on the mineralogy and composition of melt inclusions in two samples show that the Early Eocene magmatic rocks at Cape Khairyuzova were formed by mixing melts of mafic, intermediate, and acid composition, which were derived from different sources. The mafic melt was rich in MgO, and its temperature was 1100–1150°C. The temperature of the acid melt varied from 1070 to 1130°C. The melts are also different in concentrations of trace elements and in their ratios. All three melt types are enriched in LILE and LREE and depleted in HFSE and were likely derived in suprasubductional environments. The mafic and intermediate magmas were formed by melting a mantle wedge and subsequent fractionation of the melts. The acid melts could be formed by melting crustal rocks when they were overheated in the newly formed orogen of significant thickness. When ascending, the mantle melts could mix in variable proportions with acid melts in crustal chambers.     

Peculiarities of the within-year distribution of earthquakes in the Kuril region

Recent investigations have shown that the probability of the occurrence of earthquakes in a specified region depends on several factors, such as the latitude of the study region, as well as the lunar and solar tidal forces, which are governed by the mutual arrangement of bodies in the Sun-Earth-Moon system. The objective of our work is to prove that the irregularity of the within-year distribution of seismic events in the Pacific regions (the Kuril Islands and Hokkaido Island) is a statistically significant process, which is manifested in different ways for earthquakes with various source depths and energy levels. The hypothesis about the uniform within-year distribution of earthquakes is refuted for shallow events. However, it is shown that deep earthquakes are distributed uniformly. This work attempts for the first time to determine the stability degree of the within-year irregularity of seismic events with respect to the observation time interval (from 28 to 5 years). Two peaks are noted in the annual distribution of the earthquakes. The relation of the peaks of the within-year seismic activity to the Earth’s position on the ecliptic plane, as well as the relationships between the peaks, the magnitude range of the events, and the position of the specified subregion, is considered. The principal maximum of the seismic activity falls in the November-March period, which matches the minimum Earth-Sun distance.