Geochemical study of water samples taken from the Malyi Mukulan and Bol’shoi Mukulan creeks and watercourses and trickling from the pile dike of tailing pond no. 3(1) of the Tyrnyauz tungsten–molybdenum plant has been carried out. Estimation of the degree of their polluting effect on the Baksan River was made.

Anomalous concentrations of numerous major and minor elements significantly exceeding the threshold limit values (TLV) for drinking water were registered in the area of the Tyrnyauz Tungsten–Molybdenum Combine (TTMC). The maximal excess of the TLV (by one or two orders of magnitude) were obtained for Mo (up to 11 mg/L), W (4.4 mg/L), As (1.5 mg/L), Mn (8.4 mg/L), and Tl (up to 3.3 μg/L) in water of the Bolshoi Mukulan Brook flowing through the mines and three brooks flowing out from the base of the embankment of the tailing store no. 1. They are the major pollutants for water of the Baksan River. Upon flowing out to the plain, water of the Baksan River shows significant excess of the TLVs (in summer) for Al, Fe, Mn, Be, Si, Ti, Tl, and Hg.

The decontamination of buried wastes of the Tyrnyauz Tungsten–Molybdenum Plant is complicated by the geochemical features of the waste composition: low sulfide and high carbonate content, polyelemental composition, and considerable amounts of technogenic admixtures (kerosene, oils, soda, and soluble glasses). These circumstances result in sufficient complication of the suggested technology of waste treatment, including the sulfuric-acid leaching and separate sorption recovery of hazardous and useful elements from the working solution.

Wastes and tailing ponds of Tyrnyauz tungsten and molybdenum factory are the main sources of heavy metal incoming into environment in Kabardino-Balkarian Republic. The factory was closed more than 10 years ago and the recultivation of it’s tailing ponds, where accumulated hundreds of millions tones of wastes, was completed. The aim of this investigation was an assessment of their possible influence on children residing in the vicinity of these tailing ponds (village Bylym). Village Verhny Baksan located about 30 km upstream of the valley of the Baksan River was chosen as reference (pure) locality. As a results of the performed investigations we revealed that in drinking water of Bylym and Verhny Baksan concentrations of molybdenum were 2.10±0.42 pg/l and 0.31±0.15 pg/l correspondingly, which is remarkably lower than maximum permitted concentrations. The concentrations of Mo, Cu and Pb in children’s hair in both villages were practically the same, which indicates to the absence of their accumulation in human organism. But the quantity of cells with cytogenetic disorders in buccal epithelial cells in children from Bylym was 4.1 times higher in comparison with the corresponding index of uncontaminated area. The obtained data demonstrate that genotoxic effect of remedied tailing ponds retains.

Geochemical investigations of surface waters, agricultural soils, pastures, and industrial waters of the Tyrnyauz Tungsten–Molybdenum Plant (TTMP) have revealed the technogenic and natural contamination sources of the ecosystem. In 2014, the Baksan River waters on coming to the plain were contaminated in W, Mo, Nb, U, Fe, Sb, Rb, Li, Tl, and Be. The TLVs for potable water were exceeded from tenfold to thousandfold (Tl and Be). These waters are hazardous for agricultural irrigation. To decrease the negative environmental loads, the authors propose to create a technology for the treatment and utilization of technological wastes, as well as to build up the cleaning filters (ion-exchange columns of various types) for the watercourses draining the TTMP open casts.

The results of studying four mountain lakes in different climatic zones (in regions of the Kola North and the Western Caucasus) are given. Original methods of paleoecological reconstruction developed by the authors have been used to characterize the main trends and rates in environmental changes at historical scale (by geochemical composition and diatom complexes in bottom sediment layers). Similar processes of modern water enrichment by metals (especially, Cd and Pb) have been determined in the examined lakes. Trends in changes in acid-base balance in The Kola North lakes since the late XIX century have been identified, reflecting the effect of transboundary transport of acid-forming substances from industrial Europe. Studies of diatom complexes in Caucasian lakes showed a rise in the mean annual temperature of lake water during the XX century supposedly by 1.5°C.

The location features and equipment of the Neytrino seismic station are described. The examples of registering various weak local seismic events, which may be of paramount importance in researching the nature of geodynamic processes around the Elbrus volcanic center, are presented.

In addition to traditional degassing of the melt in the subsurface magma chambers of the “dormant” El’brus volcano, alsodegassing through pores and microcracks that occur in the top of magma chambers has also been detected. It is proven by studies of compactness, porosity, and permeability of the rocks. The speeds at which gases (H, He, H2S, CO2, F, and Cl) pass through gneiss and volcanic rocks were estimated. Magma chambers on the ground surface are expressed in stable thermal anomalies revealed by night-time thermal sounding from an NOAA satellite. The presence of magma chambers at depths of 2–12 km was proven by magnetotelluric sounding [Sobisevich et al., 2003] and gravity studies. In addition to occasional “columns” of bright-white fluorescence above the thermal anomalies, aerosol “clouds” and hydrogen flows were detected by lidar and hydrogen surveying [Alekseev et al., 2007, 2009]. Observation at the same sites detected steam outbursts occurring periodically, the snow-ice cover thaws and the smell of hydrogen sulfide is felt. Geochemical characteristics of degassing were studied by snow sampling from up to 1 m deep pits. They were taken within contours of the thermal anomalies, above active fault zones, in the sites of bright-white fluorescence “columns,” and on a new fumarole locality. It is shown that the degassing of melt was accompanied by the gas transporting many elements (Li, B, Si, P, S, Ca, Zn, Pb, Mo, Ba, W, Hg, Ag, U, Th, I, Au, and Pt) in a fine-grained state (a few microns or possibly nanometers) with an active participation of F and Cl. Native platinum, chalcopyrite, halite, sylvite, barite, gypsum, zircon, opal, chlorinated organics, etc. were for the first time discovered in the Mt. El’brus area using electron microscope studies of solid residue from dehydrated snow samples. “Hidden” ore mineralization genetically related to degassing of melts enriched in ore elements may be supposedly found in paleo- and present-day areas of volcanic activity.

Precaldera, caldera, and postcaldera cycles are recognized in the geological evolution of the Pleistocene-Holocene Elbrus volcanic center (EVC). During the caldera cycle, the magmatic activity was not intense, whereas hydrothermal metasomatic alteration of rocks was vigorous and extensive. The Kyukyurtli and Irik ore-magmatic systems have been revealed in the EVC, with the former being regarded as the more promising one. The ore mineralization in rocks of the caldera cycle comprises occurrences of magnetite, ilmenite, pyrite and pyrrhotite (including Ni-Co varieties), arsenopyrite, chalcopyrite, millerite, galena, and finely dispersed particles of native copper. Pyrite and pyrrhotite from volcanics of the caldera cycle and dacite of the Kyukyurtli extrusion are similar in composition and differ from these minerals of the postcaldera cycle, where pyrite and pyrrhotite are often enriched in Cu, Co, and Ni and millerite is noted as well. The composition of ore minerals indicates that the hydrothermal metasomatic alteration related to the evolution of the Kyukyurtli hydrothermal system was superimposed on rocks of the caldera cycle, whereas the late mineralization in rocks of the postcaldera cycle developed autonomously. The homogenization temperature of fluid inclusions in quartz and carbonate from crosscutting veinlets in the apical portion of the Kyukyurtli extrusion is 140–170°C and in quartz from geyserite, 120–150°C. The temperature of formation of the chalcopyrite-pyrite-pyrrhotite assemblage calculated using mineral geothermometers is 156 and 275°C in dacite from the middle and lower portions of the Malka lava flow and 190°C in dacite of the Kyukyurtli extrusion. The hydrothermal solutions that participated in metasomatic alteration of rocks pertaining to the Kyukyurtli ore-magmatic system (KOMS) and formed both secondary quartzite and geyserite were enriched in fluorine, as evidenced from the occurrence of F-bearing minerals-zharchikhite, ralstonite, α-ralstonite, and fluorite-identified in these metasomatic rocks for the first time. By analogy with porphyry Cu-Mo deposits in Chile and the United States, the ore mineralization of the KOMS may be classified by composition and textural and structural attributes as a supraore level of porphyry copper genetic type. The volcanic rocks of the KOMS and the EVC as a whole are enriched in Ag, Mo, Zn, As, Sb, Se, and Ba. Judging from the scale of argillic alteration and taking into account the data on porphyry Cu-Mo ore-magmatic systems of the Greater Caucasus, veined Pb-Zn ore mineralization may be expected in the propylitic zone at a depth down to 1000 m from the present-day erosion level of the KOMS. Stringer-disseminated Au-Ag, Cu, and Cu-Mo ore mineralization of the upper part of the porphyry ore-magmatic system related to subvolcanic dacitic intrusions may be localized somewhat deeper.

Using the new geological map of the Elbrus Volcano (scale 1:50 000) and the new isotopic datings of the volcanic rocks, the formation history of Elbrus Volcano was found to include a pre-caldera, a caldera, and a post-caldera cycle, during which the modern Elbrus stratovolcano was formed. The Early and The Late period of the volcano's evolution have been identified in the two latter cycles. ignimbrite horizons, as well as breaks in volcanic activity, represented by moraine deposits resting on the surface of lava flows in the same volcanic rock sequence. This map shows that the formation history of the Elbrus Volcano included a pre-caldera cycle, a caldera cycle, the onset of which was marked by a powerful explosive eruption, responsible for the caldera formation, and a post-caldera cycle which resulted in the formation of the present-day Elbrus stratovolcano. It is important to note that each of the two latter cycles in- cluded The Early and The Late period of the evolution of the volcano. No pre-caldera volcanic rocks have been found confidently thus far. These are supposed to include the outliers of tra- chyandesite lava flows found in the mouth of the Khudes River (up to 200 m thick) and of trachybasalt lava flows (120-150 m thick) in the upper reaches of the Tyzyl River.