The Experimental WSN Network for Underground Monitoring H2 Abundance in the Mine Atmosphere Karnasurt Mine Lovozero Layered Alkaline Intrusion

We have developed specialized equipment based on mini-MDM hydrogen sensors and the WSN telecommunication technology for long-term monitoring of hydrogen content in the environment. Unlike existing methods, the developed equipment makes it possible to carry out measurements directly in the explosion zone with high discreteness in time. This equipment was tested at a large rare-earth deposit of the Lovozero Alkaline Pluton Karnasurt in the underground mining tunnel. We observed a short time very high concentration of hydrogen in the atmosphere (more than 3 orders of normal atmosphere concentration). This discovery is very important because at the time of the explosion one can create abnormally high concentrations of explosive mixtures of hydrocarbon gases that can lead to accidents. The high resolving power of the measurement equipment makes it possible to determine the shape of the anomaly hydrogen of such a concentration and to calculate the volumes of hydrogen released from the rocks, at first time in the practice. The shape of the anomaly usually consists of 2-3 additional peaks of the shape - "dragon-head-like peak". We make an first attempt is made to explain this form of anomaly in the article. The aim of the work in the estimation hydrogen emission in mining ore deposit rare earth elements

Peralkaline Felsic Magmatism of the Atlantic Islands

The oceanic-island magmatic systems of the Atlantic Ocean exhibit significant diversity in their respective sizes, ages, and the compositional ranges of their eruptive products. Nevertheless, almost all of the Atlantic islands and island groups have produced peralkaline felsic magmas, implying that similar petrogenetic regimes may be operating throughout the Atlantic Ocean, and arguably elsewhere. The origins of peralkaline magmas are frequently linked to low-degree partial melting of enriched mantle, followed by protracted differentiation in the shallow crust. However, additional petrogenetic processes such as magma mixing, crustal melting, and contamination have been identified at numerous peralkaline centers. The onset of peralkalinity leads to magma viscosities lower than those typical for metaluminous felsic magmas, which has profound implications for processes such as crystal settling. This study represents a compilation of published and original data which demonstrates trends that suggest that the peralkaline magmas of the Atlantic Ocean islands are generated primarily via extended (up to ∼ 95%), open system fractional crystallization of mantle-derived mafic magmas. Crustal assimilation is likely to become more significant as the system matures and fusible material accumulates in the crust. Magma mixing may occur between various compositional end-members and may be recognized via hybridized intermediate magmas. The peralkaline magmas are hydrous, and frequently zoned in composition, temperature, and/or water content. They are typically stored in shallow crustal magma reservoirs (∼ 2–5 km), maintained by mafic replenishment. Low melt viscosities (1 × 101.77 to 1 × 104.77 Pa s) facilitate two-phase flow, promoting the formation of alkali-feldspar crystal mush. This mush may then contribute melt to an overlying melt lens via filter pressing or partial melting. We utilize a three-stage model to account for the establishment, development, and termination of peralkaline magmatism in the ocean island magmatic systems of the Atlantic. We suggest that the overall control on peralkaline magmatism in the Atlantic is magma flux rate, which controls the stability of upper crustal magma reservoirs. The abundance of peralkaline magmas in the Atlantic suggests that their development must be a common, but not inevitable, stage in the evolution of ocean islands

Contents of major and noble chemical elements in phosphorites and bottom sediments

Ag and Au are typically concentrated in phosphorites; they genetically related to organic matter of bottom sediments that extract these elements from seawater or interstitial water. Consequently, the phosphorites inherit Ag and Au from host sediments that are not always enriched in them. In contrast to other organic-rich sediments, analyzed sample of recent diatom ooze from the Namibian shelf is not enriched in Ag and Au, although some sediments from this region are enriched in Au. In addition to authigenic Au, allochthonous Au associated with quartz grains and micrograins can also be present in shelf phosphorites. This was observed in oceanic phosphorites of various types. Anomalous Au and Fe contents recorded in one seamount phosphorite sample can be related to extraction of Au and nonferrous metals by ferromanganese hydroxides from seawater. This process can serve as one of major mechanisms of Au supply to ferromanganese crusts on seamounts. Phosphorites and sediments are enriched in Ru simultaneously with U. Author's data show that U content varies from 17 (seamount phosphorite) to 887 ppm (Pleistocene phosphorite nodule from the Namibian shelf). This is probably caused by different types of behavior of light and heavy PGEs in the marine environment

Composition of ferromanganese crusts from the Atlantic, Pacific and Indian Oceans

A collection of layered ferromanganese ores (27 samples) from the Atlantic and Pacific oceans was studied. Trace element and PGE contents were determined layer-by-layer (up to 10 microlayers) in 13 of these samples. The trace, rare earth, and platinum group element distributions, including their layer-to-layer variations, were compared in hydrogenic and hydrothermal crusts from different regions. It was found that the main PGE variations (by a factor of 10-50) are related to their layer-to-layer variations within a given ore field. The distributions of PGE and trace elements are strongly heterogeneous, which is related, first, to different contents of the elements in the layers of different age in ferromanganese crusts (FMC) and, second, to the observed regional heterogeneity and influence of hydrothermal fluids. Geochemical data indicate that CFC formation was mainly caused by the hydrochemical precipitation of material from seawater. This process was accompanied by diagenetic phenomena, water-rock interaction, and influence of volcanic and hydrothermal sources