Fumaroles Research Articles

The Evolution of Peteroa Volcano (Chile–Argentina) Crater Lakes Between 1984 and 2020 Based on Landsat and Planet Labs Imagery Analysis

One of the major challenges in the understanding of the crater lakes dynamics and their connection with magmatic/hydrothermal processes is the continuous tracking of the physical behavior of lakes, especially in cases of remote and poorly accessible volcanoes. Peteroa volcano (Chile–Argentina border) is part of the Planchón–Peteroa–Azufre Volcanic Complex, one of the three volcanoes in the Southern Volcanic Zone of the Andes with crater lakes. Peteroa volcano is formed by a ∼5 km diameter caldera-type crater, which hosts four crater lakes and several fumarolic fields. Peteroa volcano has a large history of eruptive activity including phreatic-and-phreatomagmatic explosions and several episodes of strong degassing from its crater lakes. Here, we used TIR and SWIR bands from Landsat TM, ETM+, and OLI images available from October 1984 to December 2020 to obtain thermal parameters such as thermal radiance, brightness temperature, and heat fluxes, and Planet Labs Inc. images (RapidEye and PlanetScope) available between May 2009 and December 2020 to obtain physical parameters such as area, color, and state (liquid or frozen) of the crater lakes. We reviewed the historical eruptive activity and compared it with thermal and physical data obtained from satellite images. We determined the occurrence of two eruptive/thermal cycles: 1) Cycle 1 includes the formation of a new fumarolic field and two active craters during a short eruptive period, which includes thermal activity in three of the four crater lakes, and a strong degassing process between October 1998 and February 2001, coincident with a peak of volcanic heat flux (Qvolc) in two craters. The cycle finished with an eruptive episode (September 2010–July 2011). 2) Cycle 2 is represented by the thermal reactivation of two crater lakes, formation and detection of thermal activity in a new nested crater, and occurrence of a new eruptive episode (October 2018–April 2019). We observed a migration of the thermal and eruptive activity between the crater lakes and the interconnection of the pathways that feed the lakes, in both cases, partially related to the presence of two deep magma bodies. The Qvolc in Peteroa volcano crater lakes is primarily controlled by volcanic activity, and seasonal effects affect it at short-term, whilst at long-term, seasonal effects do not show clear influences in the volcanic heat fluxes. The maximum Qvolc measured between all crater lakes during quiescent periods was 59 MW, whereas during unrest episodes Qvolc in single crater lakes varied from 7.1 to 38 MW, with Peteroa volcano being classified as a low volcanic heat flux system. The detection of new thermal activity and increase of Qvolc in Peteroa volcano previous to explosive unrest can be considered as a good example of how thermal information from satellite images can be used to detect possible precursors to eruptive activity in volcanoes which host crater lakes.

Analysis of exposure to radon in Bulgarian rehabilitation hospitals.

Mineral springs are used in spa resorts throughout the world. Radon is a natural radioactive source, which can dissolve, accumulate, and be transported by water. This study investigates the radon concentration in air and water in 12 Bulgarian rehabilitation hospitals and presents the assessment of the exposure to radon in them. The measurements were performed at 401 premises within 21 buildings, using two types of passive detectors for a dry and wet environment that were exposed from February, 2019 to June, 2019. The radon concentration varied from 19 to 2550Bq/m3 with an arithmetic mean and a standard deviation of 102Bq/m3 and 191Bq/m3, respectively. The hypothesis that in hospitals the source of radon, besides soil under the buildings, is also the mineral water that is used for treatment was tested. Thermal water samples were procured sequentially from a spring and baths to analyse the reduction of radon concentration in them till reaching the premises. The results show that the concentration of radon decreased by approximately 50%. Further, the correlation analysis applied to the data proved the relation of the levels of indoor radon in the treatment rooms with those in the water. Mineral water used in rehabilitation hospitals have radon transfer coefficients ranging from 4.5·10-4 to 8.4·10-3. In addition, an analysis of the exposure of patients and workers to radon in rehabilitation hospitals based on the indoor radon levels and period of exposure was performed. The doses of workers do not exceed the limit of the annual effective dose for the population from all sources (1mSv/year).

Trichococcus shcherbakoviae subsp. psychrophilus subsp. nov., a psychrotolerant facultative anaerobe isolated from a cold spring.

A psychrotolerant facultative anaerobe, strain SKBGT, was isolated from the bottom sediments of the cold mineral spring Buxichen (Buryatia, Russia). Gram-positive non-motile cocci with a diameter of 1.75-2.5 µm were observed singly or in long chains. Cells grew in the temperature range from ̶ 5-35 °C. Growth was observed within the pH range of 7.0-9.5, with the optimum growth at pH 7.6 and at a NaCl concentration from 0-1.0 % (optimum 0.1 % (w/v)). Strain SKBGT was a chemoorganoheterotroph that used sugars and some organic acids as substrates. The predominant fatty acids in cell walls were С16:1ω9, С18:1ω9, and С16 : 0. The 16S rRNA gene sequence of strain SKBGT shared high similarity (>99 %) with those of the type strains of the genus Trichococcus. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SKBGT and Trichococcus shcherbakoviae ArtT (=DSM 107162T=VKM B-3260T) were 70.1 and 95.4 %, respectively. The genomic DNA G+C content of strain SKBGT was 47.1 mol%. Compared with the type strain of T. shcherbakoviae, the new strain was characterized by a temperature optimum for growth (10 °C) significantly lower than that of T. shcherbakoviae DSM 107162T (20-30 °C). Based on phenotypic and genomic characteristics, the isolate SKBGT was classified as T. shcherbakoviae subsp. psychrophilus subsp. nov. The type strain is SKBGT (=VKM B-3241Т=JCM 33326T).

Fumarolic Pathways Were Structurally Controlled by a Strike-Slip Fault System Beneath the Bishop Tuff, Bishop, California

The Volcanic Tableland, a plateau at the northern end of Owens Valley, CA, is capped by the rhyolitic Bishop Tuff. It hosts many tectonic and volcanic landforms, including hundreds of fault scarps, large joint sets, and inactive fumarolic mounds and ridges. The 1986 Chalfant Valley earthquake sequence shed light on a blind strike-slip fault system beneath the Bishop Tuff. The spatial relationships of the volcanic and tectonic structures have previously been well documented, however, the mechanisms of formation of structures and their enhancement as fumarolic pathways remain largely unexplored. We collected fault kinematic indicators, joint orientations, and documented fumarolic alterations of microcrystalline quartz in the Bishop Tuff and combined those field observations with fault response modeling to assess whether strike-slip activity played a key role in the development of fumarolic pathways. We found field evidence of dip-slip and strike-slip faulting that are consistent with the overall transtensional regional tectonics. Our modeling indicates that a blind strike-slip fault system would dilate joints in the overlying Bishop Tuff with preferred orientations that match observed orientations of joints along which fumarolic activity occurred. Our results imply that the localization of fumaroles was tectonically controlled and that fault activity in the valley floor likely initiated prior to tuff emplacement.

Influence of permeability on the hydrothermal system at Vulcano Island (Italy): inferences from numerical simulations

Volcano-hydrothermal systems are governed by complex interactions between fluid transport, and geochemical and mechanical processes. Evidence of this close interplay has been testified by distinct spatial and temporal correlations in geochemical and geophysical observations at Vulcano Island (Italy). To understand the interaction between fluid circulation and the geochemical and geophysical manifestations, we perform a parametric study to explore different scenarios by implementing a hydro-geophysical model based on the equations for heat and mass transfer in a porous medium and thermo-poroelastic theory. Numerical simulations allow us to define the controlling role of permeability distribution on the different modeled parameters as well as on the geophysical observables. Changes in the permeability within the highly fractured crater area could be responsible for the fluctuations in gas emission and temperature recorded during the crisis periods, which are accompanied by shallow volcano-seismicity in the absence of significant deformation and gravity variations. Despite the general medium permeability of the volcanic edifice, the presence of more highly permeable pathways, which allow the gas to rapidly escape, as testified by the presence of a well-developed fumarolic field, prevents the pressure buildup at shallow depths.Graphic abstract

The Pisciarelli main fumarole mechanisms reconstructed by electrical resistivity and induced polarization imaging

Pisciarelli, together with the adjacent Solfatara maar-diatreme, represents the most active structure of the Campi Flegrei caldera (Italy) in terms of degassing and seismic activity. This paper aims to define the structure of the Pisciarelli hydrothermal system (down to a 20 m depth) through electrical resistivity and time-domain-induced polarization tomography and self-potential mapping. The retrieved 3D image of the area helps reconstruct the Pisciarelli subsurface in its area of maximum degassing, containing the main fumarole (“soffione”) and the mud pool. In particular, a channel has been identified in which fluids stored in a deeper reservoir rise toward the surface. Such a structure seems to be surmounted by a clay-cap formation that could govern the circulation of fluids and the abundance of gases/vapors emitted by the soffione. Based on this new reconstruction of the Pisciarelli fumarolic field structural setting, the first conceptual model has been suggested that is capable of simultaneously explaining the mechanisms governing soffione activity and elucidating the role played by the fluid/gas of deeper origin in the shallow fluid circulation system. The proposed model can potentially help to better monitor the processes occurring throughout the Pisciarelli fumarolic field and provide an evaluation of the associated hazards.

The assessment of microbiological and physicochemical characteristics in drainage waters of the Siriu dam

Based on the balneotherapeutic applications of mineral spring water and particularly sulphurous water, the aim of our research was to study the physicochemical and microbiological parameters of some drainage waters of Siriu dam that showed a strong hydrogen sulphide odour. In addition, due to the corrosive effect of some groups of microorganisms, such as iron-oxidizing bacteria and sulphatereducing bacteria, the present paper also aimed to detect their presence in order to signal the need for some disinfection measures. According to physicochemical analysis, there has been found an external drain that is suitable for use in balneotherapy, presenting a balanced content of mineral elements such as sulphur, calcium, silicon, chlorine and potassium. However, due to the presence of potentially toxic phytoplankton microorganisms such as Microcystis sp. and Phormidium sp. it is necessary to disinfect this water source before using it for any purpose. On the other hand, the identification of both sulphate-reducing bacteria and iron-oxidizing bacteria in the drainage waters of Siriu dam should be considered as an alarm signal as they may lead to bio-corrosion and deterioration of metallic or concrete structures, affecting the integrity of the dam and hydropower constructions.

Changing hazard awareness over two decades: the case of Furnas, São Miguel (Azores)

Abstract Furnas ( c. 1500 inhabitants) lies within the caldera of Furnas volcano on the island of São Miguel (Azores) and has the potential to expose its inhabitants to multiple hazards (e.g. landslides, earthquakes, volcanic eruptions and degassing). The present population has never experienced a volcanic eruption or a major earthquake, although the catalogue records six eruptions, sub-Plinian in style, over the last 2 kyr. Today, the area experiences strong fumarolic activity. In the case of an eruption, early evacuation would be necessary to prevent inhabitants from being trapped within the caldera. An awareness of potential threats and knowledge of what to do in the case of an emergency would assist in evacuation. In this paper, inhabitants’ awareness of volcanic and seismic threats in 2017 is compared with that revealed in a similar study completed more than two decades ago. It is concluded that whereas awareness of earthquakes and the dangers posed by volcanic gas discharge has increased, knowledge of the threat of volcanic eruptions and the need to prepare for possible evacuation has not. Research suggests that the changing awareness is related to effective collaboration that has developed between the regional government, through its civil protection authorities and scientists, and the people of Furnas.

Anna Gordon’s Quest for Equality: Family, Labor, and Black Community in White Sulphur Springs, 1883–1924

Anna Gordon’s Quest for Equality: Family, Labor, and Black Community in White Sulphur Springs, 1883–1924

Microbial Communities Present in Hydrothermal Sediments from Deception Island, Antarctica

Deception Island is a geothermal location in Antarctica that presents active fumaroles, which confers unique characteristics to this habitat. Several studies about microbial communities in Antarctica have been carried out, nevertheless, Antarctic microbiota is still partially unknown. Here we present a multidisciplinary study about sediments obtained by deposition during 4 years in which several approaches have been considered for their characterization. First, a physicochemical characterization, using ionic chromatography and mass spectrometry for the determination of most abundant ions (chloride and sulphate) and elements (mainly silicon), was conducted. In addition, the total microbial community was studied using a metataxonomical approach, revealing a bacterial community dominated by Proteobacteria and Thaumarchaeota as the main archaeal genera and a fungal community mainly composed by Aspergillaceae. Culture-dependent studies showed low microbial diversity, only achieving the isolation of Bacillus-related species, some of them thermophilic, and the isolation of common fungi of Aspergillus or Penicillium spp. Furthermore, diatoms were detected in the sediment and characterized attending to their morphological characteristics using scanning electron microscopy. The study reveals a high influence of the physicochemical conditions in the microbial populations and their distribution, offering valuable data on the interaction between the island and water microbiota.

Prospects for the Development of Sustainable Tourism in the Okinsky District of the Republic of Buryatia

This article discusses the prospects for the development of sustainable tourism as an element of the network system in Okinsky District, Republic of Buryatia, RF. Before COVID-19-related restrictions, the number of tourists in this area increased annually, which was associated with the attractiveness of this terrain for visitors. The potential of the tourism sector of Okinsky District comes from the combination of a large number of natural resources. The area has rich water resources, including rivers, lakes, waterfalls, and mineral springs, with well-preserved mountainous landscapes accompanied by a centuries-old cultural and ethnic heritage. Due to Okinsky District’s specific border location and remoteness, the area has a very large number of places for recreation. The objective of our work is to clarify key factors hindering the development of tourism in the district. The study is aimed at examining the state of natural objects and determining their importance for locals, vacationers, and the district as a whole. In this regard, a problem integrity scope and a networked approach to the accompanying analysis reveal the mechanisms that contribute to the conservation of biological diversity of natural objects and their rational, scientifically grounded use in the tourism industry in accordance with the principles of sustainable development. The set of problems that impede the active promotion of tourism were identified. However, these problems are typical not only for the studied district but also many other remote areas of the Russian Federation.

Focal Mechanisms of West Bohemia, Central Europe, Earthquakes—End of May 2014: Evidence of Volume Changes

Abstract West Bohemia is a region with a lot of mineral springs and gas outflows, which seems to be related to the remains of Quaternary volcanism in Central Europe. Earthquake swarms in shallow depths (less than 15 km) are very frequent there. We focused on the strongest earthquake over the past 30 yr (31 May, 2014 Mw∼3.8) and on two smaller ones (Mw∼2.9 and 2.5) from the same day. Seismograms from local and regional seismic stations were used to calculate the full and deviatoric moment tensors using low-frequency full-waveform inversion. The studied events have similar source mechanisms. The aforementioned earthquake sequence was selected to observe the isotropic part (negative value = implosion) of full moment tensors. It could relate to the motion and phase transition of fluids, especially water, and CO2. The main goal of this study is to contribute to clarification of the nature of earthquake swarms in the western edge of the Bohemian Massif. Negative value of the isotropic part of full moment tensor could be related to the closing of cracks and fissures during a rupture process.

Effect of Hard Water on the Prevention and Treatment of Calcium Oxalate Nephrolithiasis in Rats

Background: There is a folk belief that drinking Ramsar spring mineral water (RSW) is a remedy for renal stones. Objectives: This study aimed to evaluate the effect of RSW on prevention or treatment of nephrolithiasis in male Wistar rats and identify the constituents of the water. Methods: Nephrolithiasis was induced by providing drinking water containing 1% ethylene glycol (EG) for two weeks in male Wistar rats. The animals were divided into prevention and treatment groups, each contained five sub-groups (10 rats for each). Prevention groups were treated for two weeks: control group (without treatment), EG group (1% ethylene glycol in drinking water), RSW 5, 10, and 15% groups (1% ethylene glycol + RSW 5, 10, and 15% in drinking water). The treatment groups received 1% EG for two weeks, then it was discontinued, and the RSW (10, 15, and 20%) was added to the drinking water for the next two weeks. The calcium oxalate (CaOx) depositions in the kidneys' tubules were evaluated by Hematoxylin and Eosin staining. The spring water was analyzed for its constituents. Results: Calcium oxalate crystals were significantly increased in EG group (in the prevention protocol) as compared to the control group (P < 0.01). Moreover, RSW did not significantly prevent CaOx crystals but alleviated CaOx crystals at 15 and 20% concentrations in the treatment protocol (P < 0.001). Conclusions: The hard water of Ramsar spring reduced CaOx crystals in nephrolithiatic rats, which may be due to its high calcium and magnesium content.

Analysis of Hydrothermal Systems Beneath Tayukeng through Long-Term Geochemical Signals of Hydrothermal Fluids in Tatun Volcano Group, Taiwan.

The Tatun Volcano Group (TVG) is located in northern Taiwan and consists of many springs and fumaroles. The Tayukeng (TYK) area is the most active fumarole site in the TVG. In this study, we analyzed the long-term geochemical variations of hydrothermal fluids and proposed a mechanism responsible for the variation in TYK. There are two different aquifers beneath the TYK area: a shallow SO42−-rich aquifer and a deeper aquifer rich in Cl−. TYK thermal water was mainly supplied by the shallow SO42−-rich aquifer; therefore, the thermal water showed high SO42− concentrations. After 2015, the inflow of deep thermal water increased, causing the Cl− concentrations of the TYK to increase. Notably, the inferred reservoir temperatures based on quartz geothermometry increased; however, the surface temperature of the spring decreased. We inferred that the enthalpy was lost during transportation to the surface. Therefore, the surface temperature of the spring does not increase with an increased inflow of deep hydrothermal fluid. The results can serve as a reference for understanding the complex evolution of the magma-hydrothermal system in the TVG.

The effect of sulfuric eyes on the blood and hormonalcomponents of the people who live near them in the district of Heet

Abstract This study was conducted for the period between (September 11, 2018) to (October 31, 2018) in Heet District / Anbar Governorate, on sulfur springs located in the Al-Jabal region (Al-Khader neighborhood), and it included a study of the effects of sulfur eyes on the blood and hormonal components of people Who live near it. This study included (100) women and men, and it was divided randomly into two groups ((men and women)) separately, and each group included (10 women and 10 men) and their ages ranged from 18 to 50 years. It included the following groups:- The first group:- (control group) people who are away from the sulfur spring between (100 - 200). The second Group: - People who are 10 meters away from sulfur springs. The third group:- People who are 30 meters away from the sulfur springs. Fourth group:- People who are 50 meters away from sulfur springs. Fifth group:- People who are 70 meters away from sulfur springs. The results of the effect of hydrogen sulfide H2S gas emitted from the sulfur eye showed clear significant results through the presence of a significant increase (P≤0.05)in the number of red blood cells compared to the control group at distances (10 and 30 meters), as well as a significant increase (P≤0.05)In the amount of hemoglobin at distances (10 and 30 meters) and in the number of blood platelets at distances (30 and 50 meters), a significant increase was also recorded in the number of white blood cells at a distance (50 meters) only. As for the study of the effect of sulfur eyes on hormonal changes in people living near sulfur eyes, it was found that there was a significant decrease in (10, 30 and 50 meters) for testosterone compared to the control group. The same applies to the hormone progesterone, a significant decrease in the distance was recorded (10 and 50 meters). As for the results of the field research, the observations showed a significant increase(P≤0.05) in the amount of hydrogen sulfide gas in the area near the sulfur spring, as it has a clear effect. Some people who live near it have been observed with genetic and pathological symptoms such as eye inflammation and redness, as well as there are respiratory problems and allergies in the trachea, and there are problems with the sense of smell and taste. It was noted that there are some genetic diseases on some children.

High temperature generation and equilibration of methane in terrestrial geothermal systems: Evidence from clumped isotopologues

Fluids emanating from geothermal areas contain trace quantities of methane and other simple hydrocarbons. These hydrocarbons are thought to derive from thermal cracking of organic matter dissolved in circulating meteoric or seawater or found in pre-existing organic-rich sedimentary rocks, but an abiotic origin has also been proposed. We measured the relative abundances of four CH4 isotopologues (12CH4, 13CH4, 12CH3D, and 13CH3D) in hydrothermal gases discharged by steam vents and geothermal wells from Iceland and Nisyros island (Greece) in order to investigate the origin of methane. Measured methane samples yielded consistently low Δ13CH3D values (13CH3D abundance relative to stochastic) of 0.82–1.77‰, which correspond to high apparent temperatures of isotopologue equilibrium (TΔ13CH3D = 278–490 °C). Hydrothermal well fluids from the Krafla and Námafjall geothermal fields in Iceland yielded the lowest Δ13CH3D values, and thus the highest Δ13CH3D-based temperatures averaging 438-45+55 °C. Those samples also show the most pronounced departures in δDCH4 and δ13CCH4 values expected for isotopic equilibrium with respect to δDH2O and δ13CCO2. In contrast, CH4 samples from natural steam vents in other Iceland locations and in Nisyros have slightly higher Δ13CH3D values (with TΔ13CH3D=351-35+42 °C) and have δDCH4 and δ13CCH4 values that are consistent with those expected for isotopic equilibrium with both H2O and CO2. The short fluid residence times (1–50 years) in systems that are exploited for geothermal energy, such as Krafla and Námafjall, combined with the proximity of a hot magma chamber, favor the preservation of kinetic signals. The initial disequilibrium δDCH4 and δ13CCH4 values are consistent with a thermogenic origin from immature organics dissolved in hydrothermally heated groundwater, but an abiotic origin cannot be excluded. The high apparent Δ13CH3D-based temperatures at Krafla and Námafjall could therefore represent nonequilibrium signals associated with either pyrolysis or abiotic generation of CH4 in a superheated vapor or supercritical water phase (>374 °C), considered to exist in the roots of the system above the magmatic heat source. Isotopologue equilibration calculations demonstrate that under such conditions (e.g. > 400 °C) kinetic signals would be erased in days to months, implying rapid migration and quenching of CH4 into the overlying subcritical (<300 °C) hydrothermal reservoir fluids. In systems with longer fluid residence times such as Nisyros, equilibrium isotopologue distributions at temperatures of ~ 350 °C are consistent with long fluid residence times on the order of > 100 years. Our calculations further reveal that CO2–CH4 isotopic equilibration requires unreasonably long fluid residence times, suggesting that any apparent 13C equilibrium may be coincidental.

WESTERN EXPLORERS AND VOLCANIC HEAT IN HAWAIʻI

This paper is the first to compile the accounts of Western explorers to Hawai‘i who used volcanic heat. During the 1800s, Western explorers used volcanic heat when climbing and surveying Kīlauea and Mauna Loa volcanoes in Hawai‘i. The explorers cooked food on steam vents and lava streams. They drank condensed water from volcanic steam and bathed in a warm basin and warm springs. They warmed themselves near steam cracks and a lava stream, lit cigarettes with Kīlauea’s lava lake, and collected rocks. To confirm the presence of volcanic heat, this study uses geothermal resource maps and data from the Hawai‘i Play Fairway project. The areas where the explorers used volcanic heat have a probability of volcanic heat of 0.7 to 1.0, and elevated temperatures in nearby water wells indicate heat sources. Kīlauea and Mauna Loa erupted numerous times, and the surrounding areas experienced volcanic steam releases and lava flows. The explorers used volcanic heat to facilitate not only their survival but also the Western exploration and scientific investigation of Kīlauea and Mauna Loa volcanoes.

Metabolic potential and survival strategies of microbial communities across extreme temperature gradients on Deception Island volcano, Antarctica.

Active volcanoes in Antarctica have remarkable temperature and geochemical gradients that could select for a wide variety of microbial adaptive mechanisms and metabolic pathways. Deception Island is a stratovolcano flooded by the sea, resulting in contrasting ecosystems such as permanent glaciers and active fumaroles, which creates steep gradients that have been shown to affect microbial diversity. In this study, we used shotgun metagenomics and metagenome-assembled genomes to explore the metabolic potentials and survival strategies of microbial communities along an extreme temperature gradient in fumarole and glacier sediments on Deception Island. We observed that communities from a 98 °C fumarole were significantly enriched in genes related to hyperthermophilic (e.g. reverse gyrase, GroEL/GroES and thermosome) and oxidative stress responses, as well as genes related to sulfate reduction, ammonification and carbon fixation. Communities from <80 °C fumaroles possessed more genes related osmotic, cold- and heat-shock responses, and diverse metabolic potentials, such as those related to sulfur oxidation and denitrification, while glacier communities showed abundant metabolic potentials mainly related to heterotrophy. Through the reconstruction of genomes, we were able to reveal the metabolic potentials and different survival strategies of underrepresented taxonomic groups, especially those related to Nanoarchaeota, Pyrodictiaceae and thermophilic ammonia-oxidizing archaeal lineages.

Alkali sulfates with aphthitalite-like structures from fumaroles of the Tolbachik volcano, Kamchatka, Russia. III. Solid solutions and exsolutions

ABSTRACT Six different exsolution types are found in crystals of aphthitalite-group alkali sulfates from exhalations of the active Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. The coexisting minerals in these exsolutions are metathénardite, ideally Na2SO4 (P63/mmc), and vanthoffite, Na6Mg(SO4)4 (P21/c) (Type I); metathénardite and belomarinaite, KNaSO4 (P3m1) (Type II); thénardite, Na2SO4 (Fddd), and aphthitalite, K3Na(SO4)2 (Pm1) (Type III); aphthitalite and arcanite, K2SO4 (Pnma) (Type IV); metathénardite and natroaphthitalite, KNa3(SO4)2 (Pm1) (Type V); and two chemical varieties of metathénardite (Type VI). The exsolution processes occur in crystals belonging to the high-temperature, hexagonal Na2SO4(I) (= metathénardite, P63/mmc) structure type with different K:Na ratios formed at temperatures higher than 500 °C. The similarity and hexagonal close-packed nature of the crystal structures of the coexisting phases, all representatives of aphthitalite-like structure types, cause the coherent conjugation of domains during diffusion and cation ordering in the parent phase. The breakdown of solid solution can be facilitated by the mosaic character of crystals of a parent phase (incoherent grain boundaries) and the presence of coherent twin boundaries. The heating of samples with exsolution Types II and V up to 700 °C over 24 h shows that diffusion of K and Na through the domain borders does not result in the complete disorder of these cations and the extinction of domains with different crystal structures.

الخصائص الجغرافیة والتغیرات المناخیة بمنطقة العین السخنة وعلاقتها بالنشاط البشری

تقع منطقة العين السخنة شمال غرب خليج السويس بين دائرتى عرض 29، 35o و 46، 29 شمالا وخطى طول 10، o32 و 25، o32 شرقا. تبعد منطقة الدراسة جنوب مدينة السويس بحوالي 55کم وعن مدينة القاهرة بحوالي 140کم، بينما تنحصر جغرافيا بين جبل عتاقة شمالا وهضبه الجلالة البحرية جنوبا. تتميزمنطقة الدراسة بموقع جغرافي متميز فهى محاطة بمجموعة من العوامل الجغرافية الطبيعية جعلت منها منتجع سياحي واستثماري وصناعي مهم على ساحل البحر الأحمر. يرجع تسمية منطقة الدراسة بالعين السخنة نظرا لکثرة العيون الکبريتية الساخنة بها، والتى تستخدم فى السياحة العلاجية، کما تتميز بشواطئها الرملية البيضاء غير الصخرية، حيث تنتشر على شواطئها مجموعة من القرى السياحية والفنادق. کما تتميز بمجموعة من مصانع الأسمنت والسيراميک والرخام والأمونيا وتکرير السکر، بالاضافة إلى وجود ميناء العين السخنة الذى يخدم النشاط الصناعى والسياحى. تتميز منطقة الدراسة باعتدال ظروفها المناخية مما جعلها مصيف ومشتى، بالاضافة إلى نشاط السياحة العلاجية مما جعلها مقصد للسائحين. نظرا لتدخل الانسان السلبي فى افساد الطبيعة وبناء المصانع بجوار المنشأت السياحية، والذي نتج عنه تغير بيئة منطقه الدراسة وخاصة التغير الحراري بمنطقة تصنف کمنتجع سياحي. لذلک اعتمدت الدراسة اعتمادا مباشرا على دراسة المرئيات الفضائية عبر فترات زمنية مختلفة لتوضح الاختلاف فى درجة حرارة المنطقة قبل تدخل الانسان ببناء المصانع وبعدها، کذلک المقارنة في استخدامات الأراضي قبل وبعد التدخل البشري، ومدي تأثير الرياح في تلوث البيئة المحيطة، لنضع أيدينا فوق المشکلة ومن ثم ايجاد الحلول وصياغاتها ومحاولة تطبيقها بأفضل وأحدث الوسائل الحديثة. The study area is located northwest of the Gulf of Suez, about 55km., away from Suez city and about 140km., away from Cairo. It is confined between latitudes 29 35 to 29 46 north and longitudes 32 10 to 32 25 east. Geographically, the studied area confined between Mount Ataqa to the north and plateau of Galala Al Bahariya to the south. The studied area is distinguished by a distinct geographical location, as it is surrounded by a set of natural geographical factors that made it an important tourist, investment and industrial resort on the Red Sea coast. The studied area is called Ain El Sokhna due to the large number of hot sulfur springs in it, which are used in medical tourism. It is also distinguished by its white sandy beaches that are not rocky, as there are a group of tourist villages and hotels on the shore line. The studied area is also characterized by a group of cement, ceramics, ammonia and sugar refining factories, in addition to the presence of the Ain El Sokhna port, which serves industrial and tourism activities. The studied area is characterized by moderately climatic conditions, which made it a resort and a winter resort, in addition to its medical tourism activity. However, due to the passive human intervention in spoiling nature and building factories next to the tourist facilities, which resulted in a change in the environment of the study area, especially thermal change in an area classified as a tourist resort. The study relied directly on the study of satellite visuals over different periods of time to clarify the difference in the temperature of the area before and after human intervention in building factories, as well as the comparison in land use before and after human intervention, and the extent of the impact of the winds on pollution of the surrounding environment, to put our hands above the problem and then find Solutions and their formulations and trying to implement them with the best and latest modern means.