Ca Sulfate Research Articles

Effect of Na versus Ca Sulfate Salts on the Hydration of Calcium Sulfoaluminate Clinker.

This paper examined how the amount (5% or 20%) and type (CaSO4 or Na2SO4) of sulphate salt affect the hydration of calcium sulphoaluminate clinker (KCSA). The mechanical behavior of the pastes was determined at 1, 3, 28, and 90 days, the heat flow and total heat were measured with isothermal conduction calorimetry, and the reaction products were characterized using X-ray diffraction (XRD), differential thermal analysis/thermogravimetry (DTA/TG) and scanning electron microscopy (SEM). The results obtained indicated that both the amount of sulphate salt (5% or 20%) and its type (CaSO4 or Na2SO4) affect the hydration kinetics, type of reaction products formed, and development of mechanical strength. The incorporation of CaSO4 has a positive effect on the development of the mechanical strength of KCSA. However, Na2SO4 can also produce adverse side effects at older ages. The presence of Na2SO4 increases pH values, which partly destabilizes the ettringite formed, thereby favoring carbonation and thenardite precipitation, which can cause the specimens to crack and break.

Deciphering Hydrochemistry and Fluid-Mineral Equilibria from Characteristic Low-Enthalpy Geothermal Waters of Himalaya and Eastern India

Geothermal energy, with associated low-carbon emissions compared to conventional fossil fuels, is presently one of the potential renewable energy sources. The decryption of the chemistry of thermal manifestations of geothermal systems, in terms of relative abundances of various chemical facies, is mandatory before launching systematic geothermal exploration in a given area as it provides valuable information on the basic characteristics of the geothermal reservoir. For the present study, three clusters of hot springs have been selected -1) Shyok-Nubra valleys geothermal prospect in NW Himalaya, 2) Subansiri valley geothermal areas in NE Himalaya and 3) the hot spring system occurring along Munger-Saharsa Ridge Fault Zone (MSRF) in the Eastern part of India. The study of these geothermal systems with low to moderately high temperatures of 35−75°C, has been carried out with two main objectives. The first objective is to estimate reservoir temperature and other characteristics in the three above-mentioned hot spring groups using conventional chemical geothermometry techniques for the first-hand assessment of the quality of the geothermal resource and postulating its possible application. The second objective of the study is to understand the distribution of stable isotopes (δ2H and δ18O) in the studied geothermal systems to reveal reservoir-related hydrological aspects of the geothermal system. The three groups of hot springs show large variations in total dissolved solids (TDS) from <150 to about 1800 mg/L. Enigmatic and inexplicably low TDS values of 126 to 150 mg/Lare reported from the three Bhimband hot springs along MSRF Zone. These springs discharge Ca−Mg−HCO3 type water. The dearth of dissolved ionic species in these springs indicates lack of water-rock interaction in Bhimband area. Silica is the most abundant solute species and corresponds to a reservoir temperature of about 75°C. It may be inferred that relatively inert lithology in the reservoir and very high water-to-rock ratio might have rendered the observed chemical signatures to Bhimband hot springs. Shyok-Nubra springs at Changlung and Panamik are predominantly Na-HCO3 type with TDS values of about 1700 and 550 mg/L, respectively. These hot springs give an indication of water-rock interaction in different types of lithology at temperatures of 120 to >150°C resulting in the observed chemical differences between the two. Thermal water at Taksing in NE Himalaya is also Na−HCO3 type. Chetu hot spring with TDS of >1100 mg/Lis anomalous in two ways. First, it has a very high SO4 content of 358 mg/Land second, it has the lowest silica value. There is a possibility that the Chetu hot spring has its chemistry influenced by the dissolution of sulfates of Ca and Na. Preliminary stable isotope study indicates that the geothermal fluid is derived from meteoric sources. The lack of any indication for positive δ18O-shift suggests that reservoir temperatures of the springs are generally low. Keywords: Thermal Waters, Hydrogeochemistry, Reservoir Temperature, Stable Isotopes, Himalayas, Bihar

Hydration caves and cavities from the recent weathering zone of anhydrites at Dingwall (Nova Scotia, Canada)

Hydration of anhydrite to gypsum (gypsification of anhydrite) in the weathering zone sometimes causes a volume increase. This can lead to local detachments of the surface layer of the weathering anhydrite rocks and creation of the hydration cavities and rare hydration caves (or swelling caves; German: Quellungshöhlen) inside domes formed by the uplifted layer. Currently growing hydration cavities at the anhydrite bottom of the abandoned quarry at Dingwall, Canada, were studied with the use of photogrammetric, statistic, and petrographic methods. Seventy seven cavities were documented including 48 caves (cavities with the height ≥0.30 m large enough to accommodate an adult man). Forty three caves had proper entrances (inlets large enough for an adult to get inside). The cavities contain one flat domed or, less often, tepee-like chamber generally similar in shape to the host hydration landform. The majority of cavities showed the length <4.6 m, the width <3.0 m, and the height <0.85 m. Only 3 caves had the length >8.00 m and the height ≥0.80 m. The largest and the highest cave showed the sizes 10.7 × 6.6 × 1.1 m measured in 2008 which changed into 8.87 × 2.97 × 1.35 m in 2019. The other caves and cavities exhibit also morphological changes with time due to vertical and horizontal movements of rocks slabs and collapse of the roofs depending mainly on the location of expansive gypsification and its intensity. Precipitation (rain- and meltwater) accumulating at the foot of the initial uplift intensifies the hydration in this zone causing a centripetal pressure towards the landform and contributing to its further rising and enlargement of the cavity height. The basic condition required for hydration cave formation is temperature between 0 and 30 °C in which the solubility of gypsum is much lower than that of anhydrite. The meteoric water solution infiltrating in the vadose zone is dissolving the anhydrite and gradually reaches Ca sulphate concentration higher than the level of gypsum and lower than the level of anhydrite solubility. Then, the dissolving anhydrite yields a solution supersaturated with gypsum, capable of its precipitation, and the dissolution of anhydrite is simultaneous with in situ replacive/displacive gypsum crystallization. The crystallization pressure of gypsum is a direct cause of the rock deformations and creation of hydration caves.

The Catalytic Effect of Iron and Alkali and Alkaline Earth Metal Sulfates Loading Series on the Conversion of Cellulose-Derived Hydrochars and Chars.

The catalytic effect of minerals on biomass conversion was studied focusing on Fe as well as alkali and alkaline earth metals as the metallic inorganic elements typically present in minerals found in biomass. A mineral-free reference hydrochar and an analogous char material based on cellulose were systematically doped with sulfates of the different metallic inorganic elements in various amounts via impregnation, thereby excluding differences originating from the counterion and the carbon matrix. Thermogravimetric reactivity measurements were performed in diluted O2 and CO2, and the derivative thermogravimetry curves were fitted using the random pore model. This procedure enabled a quantification of the apparent activation energy decrease due to doping as well as the influence of doping on the carbon structural parameter. Fe sulfate was always among the most active minerals, and alkali metal sulfates were typically more active than alkaline earth metal sulfates. The only exception was the high activity of very small Ca sulfate loadings during gasification. A saturation behavior of the kinetic parameter upon increasing the mineral loading was observed. The Langmuir-type modeling of this dependence further revealed that catalytically influenced devolatilization results in a char with higher oxidation reactivity, whereas for gasification, thermal annealing dominates. The systematically derived parameters provide a comprehensive description of catalytic effects, taking into account the type of mineral, the applied loading, the used atmosphere, and the fuel morphology. The derived activation energies can be used to include catalytic effects into combustion models.

Epitaxies of Ca sulfates on calcite (CaCO3). III. {010}, {001}, {100} and {011} growth forms of anhydrite (CaSO4) deposited on the {10.4} rhombohedron of calcite

Anhydrite (CaSO4) and calcite (CaCO3) are two of the main mineral structures on which there is no longer any discussion today. The problem is different when it comes to analyzing the crystal chemical relationships between them and, in particular, the crystallography arising at the epitaxial interfaces between Ca sulfates (deposits) and the peculiar {10.4} form of cleaved calcite (substrate). Recently, Ca sulfates replacing calcite have acquired great importance in addressing the epitaxy challenge. The crystallographic epi-interactions between CaSO4·2H2O gypsum and CaSO4·0.5H2O bassanite and the {10.4} form of calcite have already been analyzed in detail by this research group [Aquilano et al. (2022). CrystEngComm, 24, 5120–5127; Aquilano et al. (2022). J. Appl. Cryst. 55, 1289–1296] (parts I and II, respectively). This work is intended to complete the research, presenting the re-evaluation (part III) of anhydrite (CaSO4) epitaxially matching on the {10.4} rhombohedron of calcite.

ЦЕМЕНТИРУЮЩИЙ СЛОЙ ОТВАЛОВ КОУНРАДСКОГО РУДНИКА, ПРЕПЯТСТВУЮЩИЙ ДЕФЛЯЦИИ: МИНЕРАЛЬНЫЙ СОСТАВ, ГЕОХИМИЧЕСКИЕ ОСОБЕННОСТИ

The paper is devoted to the study of composition of the surface matter of the man-made mineral formation (MMMF), namely, tailings of the Kounradsky mine (Konyrat, Karaganda region, the Republic of Kazakhstan), and the comparison of its geochemical characteristics with the composition of aerosols. The deposit is located in an arid area of steppe zone, which is characterized by wind-formed processes, therefore, an assessment of the degree of exposure of tailing substance to them is one of the important geoecological tasks. Most of the surface of the MMMF tailings of the Kounradsky mine is composed of coarse-grained material. At the sampling points the fraction content greater 1 mm amounted to 58.7–82.5%. The moisture content for the sampling period ranged from 1.9% to 4%. It is shown that the process of an oxidation leaching of sulphide-containing substance of MMMF led to the formation of acid sulphate detached waters, which dry out quickly in dry climates, that brings about the formation of sulphate efflorescences on the surface of tailings and cementing layer. It has been determined that cement is a complex and consists of newly formed kaolinite and/or illite, jarosite, gypsum and water-soluble sulphates of Fe, Ca, Al, Mg, Na and Cu. Comparison of geochemical characteristics of aerosols collected directly at tailings and at the background point with geochemical characteristics of MMMF of the Kounradsky mine shows that today tailings are not a source of air pollutants. The source of high concentrations of Pb, Cu, Zn, As, Se, Ad, Cd in aerosols recorded at one of the points is industrial enterprises of Balkhash.

Evaluation of the effect of calcium and nano calcium on Agonoscena pistaciae (Hem.: Aphalaridae) in pistachio orchards

Calcium (Ca) is necessary for the construction of cell walls and a wide range of physiological activities in plants. In this study Ca nanoparticles were produced from a solution containing Ca Sulfate by solvothermal method and were investigated in relation to varying fertilization of macroscales and nanoparticles of Ca on one of the important pistachios pests, the common pistachio psylla, Agonoscena pistaciae, fed on pistachio saplings of Ahmadaghaei rootstock (20-year-old) in pistachio orchard. The population density of A. pistaciae was tested using complete randomized blocks with three replications and four treatments: Ca, nano-Ca, pesticide (acetamiprid), and control (distilled water). The results revealed that the influence of feeding solution on nymph and egg populations differed significantly at the % 1 level, with acetamiprid having the highest measure of control on eggs and Ca having the lowest. In addition, acetamiprid boosted nymph abundance whereas Ca lowered it.

Fossilization of Precambrian microfossils in the Volyn pegmatite, Ukraine

Abstract. We report on Precambrian microfossils from igneous rocks of the Volyn pegmatite district, associated with the Paleoproterozoic Korosten pluton, northwestern Ukraine. The fossils were recovered from meter-sized miarolitic cavities and show a well-preserved 3D morphology, mostly filamentous but with a large variety of types and also in irregular, flaky shapes reminiscent of former biofilms, as well as rare spherical objects. Based on literature data, pyrolysis experiments, and reflected light microscopy results, the organic matter (OM) is characterized as (oxy-)kerite. Further investigations with microscopic techniques, including scanning and transmission electron microscopy, and electron microprobe analysis show that fossilization likely occurred during a hydrothermal, post-pegmatitic event by silicification dominantly in the outermost 1–2 µm of the microfossils. The hydrothermal fluid, derived from the pegmatitic environment, was enriched in SiF4, Al, Ca, Na, K, Cl, and S. The OM shows O enrichment in which N and S content is low, indicating simultaneous N and S loss during anaerobic oxidation. Mineralization with Al silicates starts at the rim of the microfossils, continuing in its outer parts into identifiable encrustations and intergrowths of clay minerals, feldspar, Ca sulfate, Ca phosphate, Fe sulfide, and fluorite. Breccias, formed during collapse of some the miarolitic cavities, contain decaying OM, which released high concentrations of dissolved NH4+, responsible for the late-stage formation of tobelite-rich muscovite and buddingtonite. The age of the fossils can be restricted to the time between the pegmatite formation, at ∼1.760 Ga, and the breccia formation at ∼1.49 Ga. As the geological environment for the growth of the microorganisms and fossilization, we assume a geyser system in which the essential biological components C, N, S, and P for growth of the organisms in the miarolitic cavities were derived from microorganisms at the surface. Fossilization was induced by magmatic SiF4-rich fluids. The Volyn occurrence is a distinct and uncommon example of Precambrian fossils, and the results underline the importance of cavities in granitic rocks as a possible habitat for microorganisms preserved in the deep biosphere.

Hydrothermal Activities on C-Complex Asteroids Induced by Radioactivity

Abstract C-complex asteroids, rich in carbonaceous materials, are potential sources of Earth’s volatile inventories. They are spectrally dark resembling primitive carbonaceous meteorites, and thus, C-complex asteroids are thought to be potential parent bodies of carbonaceous meteorites. However, the substantial number of C-complex asteroids exhibits surface spectra with weaker hydroxyl absorption than water-rich carbonaceous meteorites. Rather, they best correspond to meteorites showing evidence for dehydration, commonly attributed to impact heating. Here, we report an old radiometric age of 4564.7 million years ago for Ca carbonates from the Jbilet Winselwan meteorite analogous to dehydrated C-complex asteroids. The carbonates are enclosed by a high-temperature polymorph of Ca sulfates, suggesting thermal metamorphism at &gt;300°C subsequently after aqueous alteration. This old age indicates the early onset of aqueous alteration and subsequent thermal metamorphism driven by the decay of short-lived radionuclides rather than impact heating. The breakup of original asteroids internally heated by radioactivity should result in asteroid families predominantly consisting of thermally metamorphosed materials. This explains the common occurrence of dehydrated C-complex asteroids.

Horizontal Augmentation of Chronic Mandibular Defects by the Guided Bone Regeneration Approach: A Randomized Study in Dogs.

Various biomaterial combinations have been studied focusing on their ability to stabilize blood clots and maintain space under soft tissue to support new bone formation. A popular combination is Deproteinized Bovine Bone Mineral (DBBM) placed with a native collagen membrane (NCM) tacked to native bone. In this study, we compared the outcome of this treatment option to those achieved with three different graft/membrane combinations with respect to total newly occupied area and the mineralized compound inside. After bi-lateral extraction of two mandibular premolars in five adult beagles L-shaped alveolar defects were created. A total of 20 defects healed for 6 weeks resulting in chronic type bone defects. At baseline, four options were randomly allocated to five defects each: a. DBBM + NCM with a four-pin fixation across the ridge; b. DBBM + RCLC (ribose cross-linked collagen membrane); c. DBBM + NPPM (native porcine pericardium membrane); and d. Ca-sulfate (CS) + RCLC membrane. Membranes in b/c/d were not fixed; complete tensionless wound closure was achieved by CAF. Termination after 3 months and sampling followed, and non-decalcified processing and toluidine blue staining were applied. Microscopic images obtained at standardized magnification were histomorphometrically assessed by ImageJ software (NIH). An ANOVA post hoc test was applied; histomorphometric data are presented in this paper as medians and interquartile ranges (IRs). All sites healed uneventfully, all sites were sampled and block separation followed before Technovit embedding. Two central sections per block for each group were included. Two of five specimen were lost due to processing error and were excluded from group b. New bone area was significantly greater for option b. compared to a. (p = 0.001), c. (p = 0.002), and d. (p = 0.046). Residual non-bone graft area was significantly less for option d. compared to a. (p = 0.026) or c. (p = 0.021). We conclude that collagen membranes with a prolonged resorption/barrier profile combined with bone substitutes featuring different degradation profiles sufficiently support new bone formation. Tacking strategy/membrane fixation appears redundant when using these biomaterials.

Partition of Rare Earth Elements Between Sulfate Salts Formed by the Evaporation of Acid Mine Drainage

Acid mine drainage (AMD) contains rare earth element (REE) concentrations several orders of magnitude higher than those of the rest of natural waters and could be a secondary source of REEs. In arid to semiarid climates with a long dry season, the precipitation of efflorescent sulfates constitutes a transient storage of REEs. The REE partition among the Al–Fe–Mg–Ca sulfates formed by the evaporation to dryness of six different AMDs was investigated by statistical methods and by selective dissolution. The chemical composition of the evaporitic salts showed that only three principal components (PCs) could explain more than 80% of the variability in the six samples analyzed. PC1 was associated with Ca and light REEs and interpreted as gypsum, whereas PC2 was associated with Y and heavy REEs, which were not clearly associated with a major sulfate. Finally, PC3 included Mg, Fe and several transition metals (Cu, Ni, Co, Mn and Zn) and was interpreted as Fe(II)-Mg sulfates. Selective dissolution of the salt mixtures with solutions saturated in the major sulfates revealed that the REEs were only retained in gypsum and were practically absent from the rest of the sulfates. The incorporation of REEs into gypsum decreased from Pr-Nd to La and Lu and was strictly ruled by the differences in their atomic radii and that of Ca in eight-fold coordination. However, gypsum concentrated less than 20% of the REE inventory (< 1% for Sc); the rest probably formed one or more unidentified trace minerals. This indicates that gypsum may not be an efficient way to concentrate REEs from AMD.

Investigation on ash deposition formation during co-firing of coal with wheat straw

Co-firing with coal is a promising technology for alleviating the ash-related issues during biomass combustion. This paper examines the effects of co-firing coal and straw on deposition characteristics under various biomass fractions and illustrates the mechanism of deposition formation during co-firing. Deposition experiments were conducted on a drop tube furnace with an air-cooled probe simulating the surface of the superheater. To clarify the detailed formation process of deposition, the micromorphology of deposits collected at different depths along the perpendicular direction to the deposition probe, as well as the elemental composition and mineralogy were characterized by SEM/EDS, XRF and XRD. Results showed that co-firing with coal reduced the serious slagging observed during biomass combustion, whereas resulted in higher deposition efficiency than that occurred in unblended coal/biomass combustion. As biomass fractions increased, the deposition efficiency exhibited a non-monotonic downward trend, whereas the sintering degree intensified remarkably. The formation of Ca sulfates and Fe-AAEMs aluminosilicates during co-firing led to the enrichment of Ca, S, Al, and Fe in deposits, and thus promoted melt-induced agglomeration. Viscous particles and adhesive films rich in alkali sulfates adhered closely to the probe surface were believed to be the initial layer, which triggered the deposition formation during co-firing. The inner layer composed of low-melting particles accelerated the formation and growth of deposition. Meanwhile, the fusion characteristics of coarse particles in the outer layer dominated the sintering degree. Co-firing with coal greatly alleviated the slagging tendency compared with biomass combustion, but we should be aware of the negative glue effect of AAEMs sulfates.

Response of Hybrid Tomato (Solanum lycopersiucm L) for Calcium Nutrition: Growth, Root Traits and SPAD Index

Aims: To evaluate the effect of various sources and levels of calcium fertilisation in improving the growth and SPAD index of hybrid tomato at different growth stages.&#x0D; Study Design: Factorial randomized block design (FRBD) with three replications.&#x0D; Place and Duration of Study: A field experiment was conducted in the farmer’s field at Devarayapuram village, Thondamuthur block, Coimbatore from January to April, 2021.&#x0D; Methodology: A field experiment was conducted with hybrid tomato (Solanum lycopersiucm L) Shivam by using various organic and inorganic calcium sources viz., calcium sulphate, calcium nitrate, calcium silicate, poultry manure and pressmud applied at different levels (0, 20, 40, 60, 80 kg Ca ha-1) in a factorial randomized block design with three replications. The growth parameters such as plant height, root length, lateral root length, root volume and SPAD index were recorded as per standard protocols at different plant growth stages.&#x0D; Results: A linear increase in the plant growth, root traits and SPAD index of hybrid tomato was noted by the addition of organic and inorganic sources of calcium and the highest values were observed with the application of 80 kg Ca ha-1. Higher plant height (93.8 cm), root length (16.8 cm), lateral root length (13.3 g cc-1) and SPAD index (62.0) was registered with poultry manure applied at 80 kg Ca ha-1 which was followed by pressmud applied at the same level. Skipping of calcium in the fertiliser schedule registered the lowest growth response of hybrid tomato at all the growth stages.&#x0D; Conclusion: Inorganic Ca fertiliser sources though improved the growth, root traits and SPAD index of hybrid tomato at different growth stages, and it was comparatively lesser than the organic sources such as poultry manure and pressmud as calcium sources. The order of better growth performance was: Poultry manure &gt; Pressmud &gt; Ca silicate &gt; Ca Nitrate &gt; Ca sulphate. The lowest values of all the growth attributes were noted with NPK control. It was concluded that application of poultry manure at 80 kg Ca ha-1 would be effective in improving the growth, root traits and SPAD index of hybrid tomato.

Characterization and pH neutralization products of efflorescent salts from mine tailings of (semi-)arid zones

Acidic water-soluble efflorescent salts in mining residues commonly form from sulfide oxidation and are particularly prevalent in semi-arid to arid environments. These salts are easily carried by winds and may contaminate the environment and affect human health, especially because they contain potentially toxic metals and have high solubilities. In this work, efflorescent salts from four mining sites in Mexico were characterized by X-ray diffraction and chemical analysis. They produced acidic pH values upon dissolution, and were found to be composed mostly of soluble sulfates of Ca(II), Mg(II), Zn(II) and/or Cu(II), and to a lesser extent of Fe(II/III) and/or Al, of variable stoichiometries, crystal water contents and crystallinity. Their physical and chemical characteristics varied highly depending on the underlying geochemical matrix and on the composition of the original mining residues, but gypsum was present in all samples. Two selected samples were dissolved and the solution neutralized, causing substantial precipitation of solids. The precipitates, at pH 7 were found to contain the Cu and/or Zn - rich hydroxysulfates: lahnsteinite [Zn4(OH)6SO4·3H2O], or schulenbergite [Cu3Zn4(OH)10(SO4)2]. Solubility product constants were determined on these, and on other solids produced in the absence of certain major components [such as sulfate or Zn(II)], by a combination of chemical measurements and geochemical code calculations to speciate some of the components found. These results should enhance thermodynamic properties of databases and help to predict what phases form if pH neutralization occurs or is used for remediation purposes.

On the origin of saline compounds in acidic salt flats (Central Andean Altiplano)

Volcanism, aridity, and endorheism converge in the central zone of the Andean Cordillera (Bolivia, Chile, and Argentina, between latitudes 19° S and 27° S). The Gorbea and Ignorado basins are pristine Andean sites in which the transfer of saline compounds from endogenous to exogenous environments occurs. In this area the regional volcanic rocks display strong argillic alteration, with Al and Fe (alunite, jarosite) and Ca (gypsum/anhydrite) sulfates. Native sulfur is also present in paleosolfataras. The Gorbea salt flat is covered by a discontinuous layer of selenitic gypsum of varying thickness (maximum 2 m). The discontinuity of the layer as well as its variable thickness is due to the fact that the original bed has been partially destroyed mainly by dissolution but also by deflation. Saline pond brines (Cl-SO4-Na [-Mg]) are strongly acidic reaching pH values lower than 2. The high temperature processes that caused the hydrothermal alteration in the Gorbea and Ignorado basins occurred in the Miocene (14 Ma) coinciding with a wet period that reached 9 Ma. Subsequently, the weather up to 120 ka was predominantly hyper-arid with a less arid interval between 6 and 3 Ma and the epithermal sulfates were recycled in saline lakes mainly in the Late Pleistocene wet period (120 to 11.7 ka). Evolution into the current salt flat occurred in the mid-early Holocene (11.7 to 4 ka), through a salt lake that first evolved into a ‘salina’ environment that gave rise to a selenitic gypsum layer (6.4 ka), and later to the final dryness. The highest values of δ34SVCDT and δ18OVSMOW found in the selenitic gypsum layer (+20‰ and + 28‰, respectively) show that the recycling was locally produced, mainly from isotopically heavier hypogene sulfates. The δ18OVSMOW (and less clearly, δ34SVCDT) values are higher in the basal part of the gypsum crust (about +27‰), which suggests an initial hypogene source that decreased towards the top due to mixing with supergene sulfate inputs. Bacterial activity, although catalyzing the supergene reactions, does not appear to have had a significant influence on the isotopic composition of sulfates. The crystallization water of the gypsum is isotopically lighter in the basal part of the selenitic layer (δ18OVSMOW ≈ +7‰), which indicates that the brines of the saline lake were still poorly evolved. These brines evolved to heavier (approximately +13‰) towards the top of the layer and towards the center of the salt flat, before the final drying. The partial destruction of the selenitic gypsum layer occurred during more recent wet periods over the last 4 ka that have been identified in wetlands and lakes in the Central Andean area. Isotopic data (δ34SVCDT and δ18OVSMOW) clearly suggest that sulfates in the saline compounds and evaporites from the entire Central Andean arid area have mostly a thermal origin with contributions from atmospheric deposition and locally, near the Pacific coast, marine aerosols. In addition, the great difference in altitude (approximately 3000 m) between the Altiplano and the lands located to the west, up to the Pacific coast, generated a constant flow of groundwater containing saline compounds that gave rise, to the salt flats of the basins located in lower topographic areas (Atacama, Punta Negra, Hilaricos, Soledad, Tamarugal, Salar de Pintados, Salar Grande) throughout the Cenozoic. Such salt flats have lower δ34SVCDT and δ18OVSMOW values mostly for two reasons: the secular mixing with atmospheric sulfate, and the isotope fractionation related to repetitive dissolution (or leaking)—migration—precipitation along the hydraulic gradient, a process that occurred throughout a large part of the Cenozoic. The last process also explains that the evaporites of some of these salt flats (e.g., Salar de Atacama, Salar Grande) display very high Cl/SO4 ratios.

Identification of the processes controlling groundwater quality in shallow aquifers of Moradabad city, west Uttar Pradesh, India

Present study has been carried out to identify the processes controlling groundwater quality of Moradabad city, Uttar Pradesh. A total 188 groundwater samples were collected and analyzed for major ions in pre- and post-monsoon seasons of years 2012 and 2013. Analysis results showed higher concentration of Na, K, Cl, SO4 and NO3. LL diagram showed dominance of alkalis and Cl + SO4, in three sampling seasons except in post-monsoon 2012, when Na + K–Cl + SO4 facies is recorded in 50% samples. There is dearth of HCO3 complexes in the pre-monsoon season of 2012, and then, their appearance in the post-monsoon season with alkali bicarbonates being 50%. This trend is reversed in 2013. Groundwater composition showed potential impact of varying rainfall pattern suggesting that chemistry of groundwater is intimately related to meteorological parameters. To predict minerals and their reactivity in groundwater, saturation index (SI) was calculated for pre- and post-monsoon of 2012. Groundwater is highly under-saturated with respect to halite, sulphates of Ca and fluorite and super-saturated with respect to chalcedony, quartz and talc, and these minerals may possibly be precipitated out. Relationship of SiO2 with Cl and TDS gives unequivocal evidence of anthropogenic factors having significant effect in determining the chemical characteristics of groundwater. Groundwater chemistry of the area is sum total of factors, such as, meteorological, hydrological and lithological and a set of processes related to various domains of anthropogenic activities, where variation in intensity and distribution of rainfall seems to be one of the driving factors responsible for overall temporal variations in groundwater chemistry.

Effects of oral calcium bolus supplementation on intracellular polymorphonuclear leukocyte calcium levels and functionality in primiparous and multiparous dairy cows

The objectives of this study were (1) to characterize Ca levels and polymorphonuclear leukocyte (PMN) function in primiparous and multiparous animals following oral Ca bolus supplementation, and (2) to determine differential responses of boluses containing a lower dose of Ca than traditionally used in primiparous animals on Ca levels and PMN function. Jersey × Holstein crossbred animals (n = 104) were enrolled within 24 h of parturition. All animals were blocked by time relative to calving and randomly assigned to treatment. The Ca boluses were composed of a mixture of Ca chloride, Ca sulfate, and Ca propionate. For objective 1, animals were assigned to control (CON; no Ca supplementation), or a series of 2 Ca boluses given 24 h apart for a total of 50 g of Ca. Objective 2 treatments included control (CON; no Ca supplementation), a series of 2 Ca boluses given 24 h apart containing 50 g of Ca, or a series of 2 Ca boluses given 24 h apart containing 25 g of Ca. Blood samples were collected on d 1 (<24 h), 2, 3, 5, and 7 relative to parturition. Total serum Ca, serum haptoglobin, PMN intracellular Ca, PMN intracellular Ca after stimulation with an environmental Escherichia coli, PMN L-selectin surface expression, and PMN phagocytic and oxidative burst activities were analyzed. For objective 1 a tendency was detected for a treatment difference on basal intracellular PMN Ca and a treatment difference on E. coli-stimulated intracellular PMN Ca. We detected a parity × DIM effect for PMN oxidative burst intensity. However, no other interactions or parity effects on other functional PMN variables were detectable. In primiparous animals, we found a treatment difference for E. coli-stimulated intracellular PMN Ca among animals given 50 g of Ca but no treatment difference on basal intracellular PMN Ca. The 50 g of Ca treatment increased both PMN phagocytosis and oxidative burst intensities. Supplementing animals with 50 g of oral Ca increased intracellular PMN Ca and influenced PMN function.

Hydrogen Variability in the Murray Formation, Gale Crater, Mars.

The Mars Science Laboratory (MSL) Curiosity rover is exploring the Murray formation, a sequence of heterolithic mudstones and sandstones recording fluvial deltaic and lake deposits that comprise over 350 m of sedimentary strata within Gale crater. We examine >4,500 Murray formation bedrock points, employing recent laboratory calibrations for ChemCam laser‐induced breakdown spectroscopy H measurements at millimeter scale. Bedrock in the Murray formation has an interquartile range of 2.3–3.1 wt.% H2O, similar to measurements using the Dynamic Albedo of Neutrons and Sample Analysis at Mars instruments. However, specific stratigraphic intervals include high H targets (6–18 wt.% H2O) correlated with Si, Mg, Ca, Mn, or Fe, indicating units with opal, hydrated Mg sulfates, hydrated Ca sulfates, Mn‐enriched units, and akageneite or other iron oxyhydroxides, respectively. One stratigraphic interval with higher hydrogen is the Sutton Island unit and Blunts Point unit contact, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Mg‐rich points. A second interval with higher hydrogen occurs in the Vera Rubin ridge portion of the Murray formation, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Si‐rich points. We also observe trends in the H signal with grain size, separate from chemical variation, whereby coarser‐grained rocks have higher hydrogen. Variability in the hydrogen content of rocks points to a history of water‐rock interaction at Gale crater that included changes in lake water chemistry during Murray formation deposition and multiple subsequent groundwater episodes.

Using stable isotopes to assess river water dynamics and groundwater input in the largest European Arctic river (Severnaya Dvina).

Rivers play a key role in the water cycle on the earth via integrating all hydrological channels to return terrestrial precipitations back to the oceans. In addition, rivers, together with groundwater, are powerful transformers of the surface lithosphere, responsible for chemical weathering of rocks and the removal of solute into the ocean. Tracing the dynamics of surface water and groundwater versus atmospheric feeding of rivers presents important issues in Arctic regions due to the ongoing change of the structure of hydrological runoff. In this study, stable water isotopes were used to reveal the temporal dynamics of water sources and to predict their possible change under the conditions of ongoing climate warming of the largest European Arctic river, the Severnaya Dvina, and adjacent groundwater. The isotopic composition of the river waters of the studied region is formed by the mixing of atmospheric precipitation with groundwater. The isotopic depletion in the springtime is mainly due to the recharge of thawed snow waters. A less pronounced effect in the autumn-winter period is provided by the discharge of groundwater into rivers, including the meltwater of the Last Glacial Period. This depletion is partially offset due to discharge of isotopically light thawed snow waters and is linked to evaporation in headwater streams, reservoirs, and wetlands. The isotopic composition of groundwater with low mineralization was formed throughout the Holocene and to a large extent depends on paleoclimatic conditions in the study area. In addition to fresh groundwater, brackish groundwater also takes part in the river's recharge. These brackish waters are associated with ancient and modern marine transgressions on the estuarine site and with the dissolution of Ca sulfate rocks in a karst region located in the middle reaches of the river. According to isotope data, the average annual input of the underground source to the total river flow is 25%. The results of this work will serve as the basis for continuing monitoring of the isotopic composition of river waters with an assessment of hydrological processes and observation of short as well as long-term climatic and anthropogenic impacts.

Mineralogy and Origin of Aerosol From an Arc Basaltic Eruption: Case Study of Tolbachik Volcano, Kamchatka

AbstractIntense emission of volcanic aerosol accompanied the 2012–2013 basaltic effusive eruption of Tolbachik volcano, Kamchatka. The aerosols sampled contain sulfuric acid droplets, glassy particles, and 70 mineral phases. All aerosol particles may be classified by their origin. The fragmentation aerosol includes magma fragments: silicate glass clasts, silicate microspheres, and small phenocrysts (olivine, pyroxene, and magnetite). The alteration aerosol comprises particles of quenched silicate melt covered with secondary minerals (fluorides, sulfates, and oxides/hydroxides of rock‐forming elements) and fragments of altered rocks composed solely of secondary minerals. The condensation aerosol dominated the mass during the later stages of the eruption when the explosive activity had ceased, and was characterized by the greatest variety of particle compositions. Na‐K sulfate and Fe (III) oxide comprised more than 95% of the solid fraction of the condensation aerosol. The remaining 5% was represented by native elements (Au, Ag‐Pt alloy, and Pt); sulfides of Fe, Cu, Ag, and Re; oxides and hydroxides of Al, Fe, Cu, Zn, Mo, W, Ta, and Zr; halides of Al, Mg, Na, K, Ca, Cd, Pb, Ag, and Tl; and sulfates of Na, K, Pb, Ca, and Ba; the only silicate was As‐bearing orthoclase. Droplets of H2SO4 formed the liquid phase of the condensation aerosol. Some of the aerosol components, such as magnetite spherules or phosphate‐carbonate‐fluorite association, likely had a nonvolcanic origin (country rocks and wood fly ash). The volcanic aerosols and their contained minerals, discharged at Tolbachik and elsewhere, result in a physical and chemical effect on the environment in the region of such volcanoes.