Search results for: isotopic geochemistry

Authors: Saleh O. Allehabi, V. A. Dzubaa, V. V. Flambaum, Jiguang Li, A. V. Afanasjev, S. E. Agbemava

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Recently developed versions of the configuration method for open shells, configuration interaction with perturbation theory (CIPT), and configuration interaction with many-body perturbation theory (CI+MBPT) techniques are used to study the electronic structure of Er, Fm, and No atoms. Excitation energies of odd states connected to the even ground state by electric dipole transitions, the corresponding transition rates, isotope shift, hyperfine structure, ionization potentials, and static scalar polarizabilities are calculated. The way of extracting parameters of nuclear charge distribution beyond nuclear root mean square (RMS) radius, e.g., a parameter of quadrupole deformation β, is demonstrated. In nuclei with spin > 1/2, parameter β is extracted from the quadrupole hyperfine structure. With zero nuclear spin or spin 1/2, it is impossible since quadrupole zero, so a different method was developed. The measurements of at least two atomic transitions are needed to disentangle the contributions of the changes in deformation and nuclear RMS radius into field isotopic shift. This is important for testing nuclear theory and for searching for the hypothetical island of stability. Fm and No are heavy elements approaching the superheavy region, for which the experimental data are very poor, only seven lines for the Fm element and one line for the No element. Since Er and Fm have similar electronic structures, calculations for Er serve as a guide to the accuracy of the calculations. Twenty-eight new levels of Fm atom are reported.

Keywords: atomic spectra, electronic transitions, isotope effect, electron correlation calculations for atoms

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Authors: Lixin Pei, Zhilong Huang, Wenzhe Gang

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Organic geochemistry of source rocks and oils in the Nanpu Sag, Bohai Bay basin was studied on the basis of the results of Rock-Eval and biomarker. The possible source rocks consist of the third member (Es₃) and the first member (Es₁) of Shahejie formation and the third member of Dongying Formation (Ed₃) in the Nanpu Sag. The Es₃, Es₁, and Ed₃ source rock intervals in the Nanpu Sag all have high organic-matter richness and are at hydrocarbon generating stage, which are regarded as effective source rocks. The three possible source rock intervals have different biomarker associations and can be differentiated by gammacerane/αβ C₃₀ hopane, ETR ([C₂₈+C₂₉]/ [C₂₈+C₂₉+Ts]), C₂₇ diasterane/sterane and C₂₇/C₂₉ steranes, which suggests they deposited in different environments. Based on the oil-source rock correlation, the shallow oils mainly originated from the Es₃ and Es₁ source rocks in the Nanpu Sag. Through hydrocarbon generation and expulsion history of the source rocks, trap development history and accumulation history, the shallow oils mainly originated from paleo-reservoirs in the Es₃ and Es₁ during the period of Neotectonism, and the residual paleo-reservoirs in the Es₃ and Es₁ would be the focus targets in the Nanpu Sag; Bohai Bay Basin.

Keywords: source rock, biomarker association, Nanpu Sag, Bohai Bay Basin

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Authors: Raluca Popescu, Diana Costinel, Elisabeta-Irina Geana, Oana-Romina Botoran, Roxana-Elena Ionete, Yazan Falah Jadee 'Alabedallat, Mihai Botu

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Walnut production is high in Romania, different varieties being cultivated dependent on high yield, disease resistance or quality of produce. Walnuts have a highly nutritional composition, the kernels containing essential fatty acids, where the unsaturated fraction is higher than in other types of nuts, quinones, tannins, minerals. Walnut consumption can lower the cholesterol, improve the arterial function and reduce inflammation. The purpose of this study is to determine and compare the composition of walnuts of indigenous and international varieties all grown in Romania, in order to identify high-quality indigenous varieties. Oil has been extracted from the nuts of 34 varieties, the fatty acids composition and IV (iodine value) being afterwards measured by NMR. Furthermore, δ13C of the extracted oil had been measured by IRMS to find specific isotopic fingerprints that can be used in authenticating the varieties. Chemometrics had been applied to the data in order to identify similarities and differences between the varieties. The total saturated fatty acids content (SFA) varied between n.d. and 23% molar, oleic acid between 17 and 35%, linoleic acid between 38 and 59%, linolenic acid between 8 and 14%, corresponding to iodine values (IV - total amount of unsaturation) ranging from 100 to 135. The varieties separated in four groups according to the fatty acids composition, each group containing an international variety, making possible the classification of the indigenous ones. At both ends of the unsaturation spectrum, international varieties had been found.

Keywords: δ13C-IRMS, fatty acids composition, 1H-NMR, walnut varieties

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Authors: Dionisios Panagiotaras, Pavlos Avramidis, Dimitrios Papoulis, Dionysios Koulougliotis, Dionisis C. Christodoulopoulos, Dimitra Lekka, Despoina Nifora, Denisa Drouvari, Alexandra Skalioti

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This study delineates the geochemical and mineralogical characteristics of soils collected from woodland and forest areas affected by the fires of August 2021 at the Ilia prefecture, Greece. The mineralogical composition of the samples consists of quartz, calcite, albite, oligoclase, anorthite (feldspars), smectite, kaolinite and illite (clays). Quartz ranges from 38.21% to 57.49% with an average of 48.43%, calcite ranges from 2.55% to 25.09% with an average of 13.92%, feldspars ranges from 7.76% to 25.87% with an average of 17.02% and clays ranges from 4.39% to 43.43% with an average of 20.63%. Geochemical analyses of the soil samples applied for total organic carbon (TOC), total nitrogen (TN), total phosphorous (TP), Cu, Zn, Mn and Fe. Statistical analysis of the data shows a positive correlation between clays and Zn, Mn, Fe. TOC and TN show a strong positive correlation, while Fe shows a strong negative correlation with calcite.

Keywords: soils, geochemistry, mineralogy, woodland, forest

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Authors: Fakher Eddine Messaoudi

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The M'Taguinarou North iron occurrence contains Iron and polymetallic mineralization (Fe-Zn-Cu), hosted in Turonian limestone. It manifests in metric clusters of goethite and hematite and in centimetre veins of smithsonite, malachite, and azurite. The genesis of this mineralization is clearly polyphased and results from the supergene processes superposed on hydrothermal phases where the Triassic diapirs probably generated the circulation of hydrothermal fluids through the sedimentary series, and the alteration of the Turonian limestone gave the formation of the hydrothermal primary ore composed of iron carbonates (siderite). Several uplift episodes affected the mineralization and the host rocks, generating the genesis of a polymetallic supergene assembly (goethite, malachite, azurite, quartz, and calcite). In M’taguinarou North, iron oxy-hydroxides are mainly observed in the form of fibrous stalactites, stalagmites, and Botroydale structures, where hematite precipitated first, followed immediately by goethite, limonite, and smithsonite. Siderite is completely absent. Subsequently, malachite, azurite, and calcite formed in the form of small veins intersecting the surrounding limestone.

Keywords: mineralization, genetic model, hydrothermal iron, supergene, Tebessa, Algeria

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Authors: Chatkaew Tansakul, Saovajit Nanruksa, Surasak Chonchirdsin

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Heavy metals in the environment can be occurred by both natural weathering process and human activity, which may present significant risks to human health and the wider environment. A number of heavy metals, i.e. Arsenic (As) and Manganese (Mn), are found with a relatively high concentration in the northern part of Thailand that was assumptively from natural parent rocks and materials. However, scarce literature is challenging to identify the accurate root cause and best available explanation. This study is, therefore, aim to gather heavy metals data in 5 provinces of the North of Thailand where PTT Exploration and Production (PTTEP) public company limited has operated for more than 20 years. A thousand heavy metal analysis is collected and interpreted in term of Enrichment Factor (EF). The trend and distribution of heavy metals in soil and sediment are analyzed by considering altogether the geochemistry of the regional soil and rock. . In addition, the relationship between land use and heavy metals distribution is investigated. In the first conclusion, heavy metal concentrations of (As) and (Mn) in the studied areas are equal to 7.0 and 588.6 ppm, respectively, which are comparable to those in regional parent materials (1 – 12 and 850 – 1,000 ppm for As and Mn respectively). Moreover, there is an insignificant escalation of the heavy metals in these studied areas over two decades.

Keywords: contaminated soil, enrichment factor, heavy metals, parent materials in North of Thailand

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Authors: Kazushi Murata, Fabian Watermann, O. B. Herve Gonroudobou, Le Thuy Hang, Toshiro Yamanaka, M. Larry Lopez C.

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Aims: Black pine coastal forests play an important role as a windbreak and as a natural barrier to sand and salt spray inland in Japan. The recent invasion of N₂-fxing black locust (Robinia pseudoacacia) trees in these forests is expected to have a nutritional contribution to black pine trees growth. Thus, the effect of this new source of N on black pine trees' N assimilation needs to be assessed. Methods: In order to evaluate this contribution, tree-ring isotopic composition (δ¹⁵N) and nitrogen content (%N) of black pine (Pinus thunbergii) trees in a pure stand (BPP) and a mixed stand (BPM) with black locust (BL) trees were measured for the period 2000–2019 for BPP and BL and 1990–2019 for BPM. The same measurements were conducted in plant tissues and in soil samples. Results: The tree ring δ15N values showed that for the last 30 years, BPM trees gradually switched from BPP to BL-derived soil N starting in the 1990s, becoming the dominant N source from 2000 as no significant diference was found between BPM and BL tree ring δ¹⁵N values from 2000 to 2019. No difference in root and sapwood BPM and BL δ¹⁵N values were found, but BPM foliage (−2.1‰) was different to BPP (−4.4‰) and BL (−0.3‰), which is related to the different N assimilation pathways between BP and BL. Conclusions: Based on the results of this study, the assimilation of BL-derived N inferred from the BPM tissues' δ¹⁵N values is the result of an increase in soil bioavailable N with a higher δ¹⁵N value.

Keywords: nitrogen-15, N₂-fxing species, mixed stand, soil, tree rings

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Authors: Deepanjali Gurav, Kun Qian

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In-vitro metabolic diagnosis relies on designed materials-based analytical platforms for detection of selected metabolites in biological samples, which has a key role in disease detection and therapeutic evaluation in clinics. However, the basic challenge deals with developing a simple approach for metabolic analysis in bio-samples with high sample complexity and low molecular abundance. In this work, we report a designer plasmonic nanoshells based platform for direct detection of small metabolites in clinical samples for in-vitro metabolic diagnostics. We first synthesized a series of plasmonic core-shell particles with tunable nanoshell structures. The optimized plasmonic nanoshells as new matrices allowed fast, multiplex, sensitive, and selective LDI MS (Laser desorption/ionization mass spectrometry) detection of small metabolites in 0.5 μL of bio-fluids without enrichment or purification. Furthermore, coupling with isotopic quantification of selected metabolites, we demonstrated the use of these plasmonic nanoshells for disease detection and therapeutic evaluation in clinics. For disease detection, we identified patients with postoperative brain infection through glucose quantitation and daily monitoring by cerebrospinal fluid (CSF) analysis. For therapeutic evaluation, we investigated drug distribution in blood and CSF systems and validated the function and permeability of blood-brain/CSF-barriers, during therapeutic treatment of patients with cerebral edema for pharmacokinetic study. Our work sheds light on the design of materials for high-performance metabolic analysis and precision diagnostics in real cases.

Keywords: plasmonic nanoparticles, metabolites, fingerprinting, mass spectrometry, in-vitro diagnostics

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Authors: Maris Klavins, Valery Rodinov

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The aim of this study was to analyze long term changes of surface water quality in Latvia, spatial variability of water chemical composition, possible impacts of different pollution sources as well as to analyze the measures to protect national water resources - river basin management. Within this study, the concentrations of major water ingredients and microelements in major rivers and lakes of Latvia have been determined. Metal concentrations in river and lake waters were compared with water chemical composition. The mean concentrations of trace metals in inland waters of Latvia are appreciably lower than the estimated world averages for river waters and close to or lower than background values, unless regional impacts determined by local geochemistry. This may be explained by a comparatively lower level of anthropogenic load. In the same time in several places, direct anthropogenic impacts are evident, regarding influences of point sources both transboundary transport impacts. Also, different processes related to pollution of surface waters in Latvia have been analyzed. At first the analysis of changes and composition of pollutant emissions in Latvia has been realized, and the obtained results were compared with actual composition of atmospheric precipitation and their changes in time.

Keywords: water quality, trend analysis, pollution, human impact

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Authors: Ana Maria Carmen Ilie, Carmela Vaccaro

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Gas migration through wellbore failure, in particular from abandoned wells, is repeatedly identified as the highest risk mechanism. The vadose zone was subject to monitoring system close to the wellbore in Minerbio, methane storage site. The new technology has been well-developed and used with the purpose to provide reliable estimates of leakage parameters. Of these techniques, soil flux sampling at the soil surface, via the accumulation chamber method and soil flux sampling at the depths of 100cm below the ground surface, have been an important technique for characterizing the gas concentrations at the gas storage site. We present results of soil Radon Bq/m3, CO2%, CH4% and O2% concentration gases. Measurements have been taken for radon concentrations with an Durridge RAD7 Company, Inc., USA, instrument. We used for air and soil quality an Biogas ETG instrument monitoring system, with NDIR CO2, CH4 gas sensor and electrochemical O2 gas sensor. The measurements started in September-October 2015, where no outliers have been identified. The measurements have continued in March-April-July-August-September 2016, almost at the same time in the same place around the gas storage site, values measured 15 minutes for each sampling, to determine their concentration, their distribution and to understand the relationship among gases and atmospheric conditions. At a depth of 100 cm, the maximum soil radon gas concentrations were found to be 1770 ±±582 Bq/m3, the soil consists of 64.31% sand, 20.75% silt and 14.94% clay, and with 0.526 ppm of Uranium. The maximum concentration (September 2016), in soil at 100cm below the ground surface, with 83% sand, 8.96% silt and 7.89% clay, was about 0.06% CH4, and in atmosphere 0.06% CH4 at 40°C (T). In the other months the values have been on the range of 0.01% to 0.03% CH4. Since we did not have outliers in the gas storage site, soil-gas samples for isotopic analysis have not been done.

Keywords: leakage gas monitoring, lithology, soil gas, methane

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Authors: M. Budakoglu, M. Karaman, A. Abdelnasser, D. Kiran, M. Kumral

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About 50 mg lake sediment was digested in two steps. While first stage was completed with 6 ml 37% HCl, 2 ml 65% HNO3 and 1 ml 38-40% HF in an pressure and temperature controlled Teflon beaker using Berghoff Microwave™ at average 135°C, digestion procedure was completed with the addition of 6 ml 5% boric acid solution. REE contents of sediment samples were determined by Perkin Elmer DRC II ICP-MS in Geochemistry Research Laboratories (JAL/GRL) of Faculty of Mines, Istanbul Technical University. Chondrite-normalized REE patterns of Lake Acıgöl sediments show generally high abundance of REE compared to chondritic concentrations, with particular enrichment in LREE [(La/Lu)N = 4.85-19.90], [(La/Lu)N = 7.09-15.14], [(La/Lu)N = 9.42-15.52] and [(La/Lu)N = 7.69-15.63] for the surface sediment and 0-10 cm-, 10-20 cm- and 20-30 cm-subsurface sediments respectively. Also these samples showed flat HREE normalized to chondrite as (La/Sm)N ranging from 2.98 to 4.8 for surface sediments and for subsurface sediments from 3.28 to 3.97 (0-10 cm), 3.57 to 3.94 (10-20 cm) and 3.36 to 3.94 (20-30 cm) while (Gd/Yb)N ranging from 2.14 to 2.93, from 2.03 to 2.76, from 2.26 to 2.79 and from 2.05 to 2.76 from the surface and subsurface sediments respectively. Moreover, their REE profiles are similar to profiles of the continental collision basin (CCB) with negative Eu anomalies. In addition, their REE patterns illustrate generally low abundance of REE compared to concentrations of NASC, PAAS and UCC with very slight enrichment of LREE and positive Eu* anomalies. Therefore there is no comparable between our samples of surface and subsurface sediments and these types of international sediments.

Keywords: chondrite-normalized REE patterns, hypersaline lake, surface sediments, subsurface sediments, Lake Acıgöl, Turkey

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Authors: Mojtaba Heydarizad

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Andarokh basin is one of the main karstic regions in Khorasan Razavi province NE Iran. This basin is part of Kopeh-Dagh mega zone extending from Caspian Sea in the east to northern Afghanistan in the west. This basin is covered by Mozdooran Formation, Ngr evaporative formation and quaternary alluvium deposits in descending order of age. Mozdooran carbonate formation is notably karstified. The main surface karstic features in Mozdooran formation are Groove karren, Cleft karren, Rain pit, Rill karren, Tritt karren, Kamintza, Domes, and Table karren. In addition to surface features, deep karstic feature Andarokh Cave also exists in the region. Studying Ca, Mg, Mn, Sr, Fe concentration and Sr/Mn ratio in Mozdooran formation samples with distance to main faults and joints system using PCA analyses demonstrates intense meteoric digenesis role in controlling carbonate rock geochemistry. The karst evaluation in Andarokh basin varies from early stages 'deep seated karst' in Mesozoic to mature karstic system 'Exhumed karst' in quaternary period. Andarokh cave (the main cave in Andarokh basin) is rudimentary branch work consists of three passages of A, B and C and two entrances Andarokh and Sky.

Keywords: Andarokh basin, Andarokh cave, geochemical analyses, karst evaluation

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Authors: Rotondwa P. Gunununu, Mustapha Mohammed, Felix D. Dakora

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Common bean is the most importantly high protein grain legume grown in Southern Africa for human consumption and income generation. Although common bean can associate with rhizobia to fix N₂ for bacterial use and plant growth, it is reported to be a poor nitrogen fixer when compared to other legumes. N₂ fixation can vary with legume species, genotype and rhizobial strain. Therefore, screening legume germplasm can reveal rhizobia/genotype combinations with high N₂-fixing efficiency for use by farmers. This study assessed symbiotic performance and N₂ fixation in 63 common bean genotypes under field conditions at Malkerns Station in Eswatini, using the ¹⁵N natural abundance technique. The shoots of common bean genotypes were sampled at a pod-filling stage, oven-dried (65oC for 72h), weighed, ground into a fine powder (0.50 mm sieve), and subjected to ¹⁵N/¹⁴N isotopic analysis using mass spectrometry. At maturity, plants from the inner rows were harvested for the determination of grain yield. The results revealed significantly higher modulation (p≤0.05) in genotypes MCA98 and CIM-RM01-97-8 relative to the other genotypes. Shoot N concentration was highest in genotype MCA 98, followed by KAB 10 F2.8-84, with most genotypes showing shoot N concentrations below 2%. Percent N derived from atmospheric N₂ fixation (%Ndfa) differed markedly among genotypes, with CIM-RM01-92-3 and DAB 174, respectively, recording the highest values of 66.65% and 66.22 % N derived from fixation. There were also significant differences in grain yield, with CIM-RM02-79-1 producing the highest yield (3618.75 kg/ha). These results represent an important contribution in the profiling of symbiotic functioning of common bean germplasm for improved N₂ fixation.

Keywords: nitrogen fixation, %Ndfa, ¹⁵N natural abundance, grain yield

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Authors: Hai Zhou, Wenzhi Zhao

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Water is one of the most important factors limiting plant growth and development in desert ecosystems. In order to understand how desert shrubs cope with variation in water sources over time, it is important to understand plant–water relations in desert-oasis ecotone. We selected the typical desert shrubs: Nitraria sibirica, Calligonum mongolicum and Haloxylon ammodendron of 5-, 10-, 20- and 40-year old as the research species, to study the seasonal variation of plant water sources and response to precipitation in the desert-oasis ecotone of Linze, Northwestern China. We examined stable isotopic ratios of oxygen (δ18O) in stem water of desert shrubs as well as in precipitation, groundwater, and soil water in different soil layers and seasons to determine water sources for the shrubs. We found that the N. sibirica and H. ammodendron of 5-, 10-year old showed significant seasonal variation characteristics of δ18O value of stem water and water sources. However, the C. mongolicum and 20- and 40-year H. ammodendron main water sources were from deep soil water and groundwater, and less response to precipitation pulse. After 22.4 mm precipitation, the contribution of shallow soil water (0-50cm) to the use of N. sibirica increased from 6.7% to 36.5%; the C. mongolicum rarely use precipitation that were about 58.29% and 23.51%, absorbed from the deep soil water and groundwater; the contribution of precipitation to use of H. ammodendron had significantly differences among the four ages. The H. ammodendron of 5- and 10-year old about 86.3% and 42.5% water sources absorbed from the shallow soil water after precipitation. However, the contribution to 20- and 40-year old plant was less than 15%. So, the precipitation was one of the main water sources for desert shrubs, but the species showed different water utilization. We conclude that the main water source of the N. sibirica and H. ammodendron of 5-, 10-year was soil water recharged by precipitation, but the deeply rooted H. ammodendron of 20‐ and 40‐year‐old and the C. mongolicum have the ability to exploit a deep and reliable water source.

Keywords: water use pattern, water resource, stable isotope, seasonal change, precipitation pulse

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Authors: Zayre I. Gonzalez-Acevedo, Marco A. Garcia-Zarate

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Environmental pollution by heavy metals is due to several processes, whether natural as weathering, or anthropogenic, related to human activities. Geysers may content dissolved heavy metals, related with their geothermal origin, and they are widely used by local people and tourists for treatment of dermal diseases and other therapeutic applications. In this study, 20 geysers with temperatures between 32 to 94 °C, located in the vicinity of Queretaro and Guanajuato in Central Mexico, were studied. These geysers were sampled in dry and rainy seasons in order to investigate seasonal changes of trace elements. The samples were analyzed in SWAMP Lab, University of Alberta, Canada for 34 elements. Most of the analyzed trace elements sowed concentrations below guidelines for natural waters. The elements showed seasonal variability with higher concentrations during rainy season. Arsenic varied from 49.29 to 2.16 µg L⁻¹. Arsenic was highly correlated with Fe, Sr, Th and Tl. Barium varied from 93.52 to 1.79 µg L⁻¹. Barium was highly correlated with Co, Cr, Mo, Ni, U, V, and Y. Copper and Zinc were correlated as well. According to the comparison of sites and the correlations between trace elements, their source was identified as natural regional, geothermal or anthropogenic origin. Because of application of geyser's water to balneology and health treatments, and also, because they are located in an urban zone in development, advise on their direct uses, according to their environmental quality is appointed in this research.

Keywords: balneology, direct uses, environmental quality and trace elements

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Authors: Yue Feng, Chun-jiang Wang, Zhi-long Huang

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The study of the sedimentary environment of Mesoproterozoic marine deposits in North China has attracted special attention in recent years. It is not clear that the sedimentary environment and the cause of formation of the sandstone strip and its internal carbonate cements and pyrite in the Mesoproterozoic Chuanlinggou Formation in North China. In this study, drilling core samples in North China were identified by microscopy, and their petrological characteristics such as mineral composition and structure were identified. The geochemical data of carbon and oxygen isotopes, total organic carbon (TOC) contents and total sulfur (TS) contents were obtained by processing and analyzing the samples. The samples are mainly quartz particles with low compositional maturity, combined with low value of TOC, it shows that the sedimentary environment of the sandy clastic is a sandy littoral sedimentary environment with relative strong hydrodynamic force, and then the sandstone strip in black shale are formed by the deposition of gravity flow. Analysis of TS values reflect sandstone bands formed in hypoxic environments. The carbonate cements and the pyrite in the sandstone belt are authigenic. The carbon isotope values of authigenic carbonate cements are negatively biased in comparison with the carbonate isotope of carbonate rocks in the same period, but it is more biased than the carbon isotopic values of anaerobic oxidation of methane (AOM) genetic carbonate rocks. Authigenic pyrite may be mainly due to the formation of HS- by the action of bacterial sulfate reduction (BSR) and Fe²⁺, their causes are in contact. This indicates that authigenic carbonate cements are mainly carbonate precipitates formed but are significantly affected by the effects of AOM. Summary, the sedimentary environment of the sandstone zone in the Chuanlinggou Formation in the North China is a shallow sea facies with iron rich and anoxic.

Keywords: sandstone strip, sedimentary environment, authigenic carbonate cements, authigenic pyrite, The Chuanlinggou group, North China

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Authors: Anis Belhaj Mohamed, Moncef Saidi, Mohamed Soussi, Ibrahim Bouazizi, Monia Ben Jrad

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This paper summarizes the results of Rock-Eval pyrolysis and biomarker data of shale samples collected from the Ordovician age (Llanvirnian-Llandeilian) (Azzel Formation) in the Chotts basin southern part of Tunisia. The results are supported by analysis of cutting samples from wells. The Azzel shales has poor to moderate, occasionally good, potential for sourcing oil and gas with Total Organic Carbon (TOC) content varying from 0.80 to 4.49 % and petroleum potential (PP) values varying between 0.68 to 9.20 Kg of HC/t rock in Baguel and Alaguia wells. However, the Azzel Formation show poor to fair TOC and PP in Elfranig and HajBrahim wells not exceeding 1.10% and 1.05 kg HC/t of rock respectively. The Hydrogen Index (HI) and the Oxygen Index (OI) values of 95–165 mg S2/g TOC and of 33–108 mg CO2/g rock relatively show that the Ordovician shales exhibit type II Kerogen that reached the main oil window stage and that the organic matter was bad preserved, Tmax values of 435 – 448°C indicate the organic matter is mature. The biomarker features of the extract samples are characterized by high proportion of tricyclic terpanes that are dominated by C23 and C21 tricyclic terpanes. The hopanes fraction is dominated by C29 and C30 hopanes. The Ordovician shales show a predominance of C27 over C29 steranes (C27/C29>1) and relatively high proportions of diasteranes supporting the shaly character of the source rock.

Keywords: biomarkers, organic geochemistry, ordovician source rock, diasteranes

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Authors: Abdelbasset Tounekti, Kamel Boukhalfa, Tathagata Roy Choudhury, Mohamed Soussi, Santanu Banerjee

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The exceptionally glauconite-rich Miocene strata are superbly exposed throughout the front of the nappes zone of northern Tunisia. Each of the glauconitic fine-grained intervals coincide with the peak rise of third order sea-level cycles during the Burdigalian-Langhiantime. These deposits show coarsening- and thickening-upward glauconitic shale and sandstone, recording a shallowing upward progression across offshore-shoreface settings. Petrographic investigation reveals that the glauconite was originated from the alteration of fecal pellets, and lithoclast including feldspar, volcanic particle, and quartz and infillings with intraparticle pores. Mineralogical analysis of both randomly oriented and air-dried, ethylene-glycolate, and heated glauconite pellets show the low intensity of (002) reflection peaks, indicating high iron substitution for aluminum in octahedral sites. Geochemical characterization of the Miocene glauconite reveals a high K2O and variable Fe2O3 (total) content. A combination of layer lattice and divertissement theories explains the origin of glauconite. The formation of glauconite was facilitated by the abundant supply of Fe through contemporaneous volcanism in Algeria and surrounding areas, which accompanied the African-European plate convergence. Therefore, the occurrence of glauconite in the Miocene succession of Tunisia is influenced by the combination of eustacy and volcanism.

Keywords: glauconite, autogenic, volcanism, geochemistry, chamosite, northern Tunisia, miocene

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Authors: Rodrigo Antunes, Olga Borisevich, David Demange

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In future nuclear fusion reactors, tritium self-sufficiency will be ensured by tritium (3H) production via reactions between the fusion neutrons and lithium. To favor tritium breeding, a neutron multiplier must also be used. Both tritium breeder and neutron multiplier will be placed in the so-called Breeding Blanket (BB). For the European Helium-Cooled Pebble Bed (HCPB) BB concept, the tritium production and neutron multiplication will be ensured by neutron bombardment of Li4SiO4 and Be pebbles, respectively. The produced tritium is extracted from the pebbles by purging them with large flows of He (~ 104 Nm3h-1), doped with small amounts of H2 (~ 0.1 vol%) to promote tritium extraction via isotopic exchange (producing HT). Due to the presence of oxygen in the pebbles, production of tritiated water is unavoidable. Therefore, the purging gas downstream of the BB will be composed by Q2/Q2O/He (Q = 1H, 2H, 3H), with Q2/Q2O down to ppm levels, which must be further processed for tritium recovery. A two-stage continuous approach, where zeolite membranes (ZMs) are followed by a catalytic membrane reactor (CMR), has been recently proposed to fulfil this task. The tritium recovery from Q2/Q2O/He is ensured by the CMR, that requires a reduction of the gas flow coming from the BB and a pre-concentration of Q2 and Q2O to be efficient. For this reason, and to keep this stage with reasonable dimensions, ZMs are required upfront to reduce as much as possible the He flows and concentrate the Q2/Q2O species. Therefore, experimental activities have been carried out at the Tritium Laboratory Karlsruhe (TLK) to test the separation performances of different zeolite membranes for H2/H2O/He. First experiments have been performed with binary mixtures of H2/He and H2O/He with commercial MFI-ZSM5 and NaA zeolite-type membranes. Only the MFI-ZSM5 demonstrated selectivity towards H2, with a separation factor around 1.5, and H2 permeances around 0.72 µmolm-2s-1Pa-1, rather independent for feed concentrations in the range 0.1 vol%-10 vol% H2/He. The experiments with H2O/He have demonstrated that the separation factor towards H2O is highly dependent on the feed concentration and temperature. For instance, at 0.2 vol% H2O/He the separation factor with NaA is below 2 and around 1000 at 5 vol% H2O/He, at 30°C. Overall, both membranes demonstrated complementary results at equivalent temperatures. In fact, at low feed concentrations ( ≤ 1 vol% H2O/He) MFI-ZSM5 separates better than NaA, whereas the latter has higher separation factors for higher inlet water content ( ≥ 5 vol% H2O/He). In this contribution, the results obtained with both MFI-ZSM5 and NaA membranes for H2/He and H2O/H2 mixtures at different concentrations and temperatures are compared and discussed.

Keywords: nuclear fusion, gas separation, tritium processes, zeolite membranes

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Authors: Naresh Kumar, Radhika Sharma, A. K. Singh

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Acid plutonic rocks from the Khanak and Devsar areas of southwestern Haryana were investigated to understand their geochemical and petrogenetic characteristics and tectonic environments. Three dominant rock types (grey, grayish green and pink granites) are the principal geochemical features of Khanak and Devsar areas which reflect the dependencies of their composition on varied geological environment during the anorogenic magmatism. These rocks are enriched in SiO₂, Na₂O+K₂O, Fe/Mg, Rb, Zr, Y, Th, U, REE (Rare Earth Elements) enriched and depleted in MgO, CaO, Sr, P, Ti, Ni, Cr, V and Eu and exhibit a clear affinity to the within-plate granites that were emplaced in an extensional tectonic environment. Chondrite-normalized REE patterns show enriched LREE (Light Rare Earth Elements), moderate to strong negative Eu anomalies and flat heavy REE and grey and grayish green is different from pink granite which is enriched by Rb, Ga, Nb, Th, U, Y and HREE (Heavy Rare Earth Elements) concentrations. The composition of parental magma of both areas corresponds to mafic source contaminated with crustal materials. Petrogenetic modelling suggest that the acid plutonic rocks might have been generated from a basaltic source by partial melting (15-25%) leaving a residue with 35% plagioclase, 25% alkali feldspar, 25% quartz, 7% orthopyroxene, 5% biotite and 3% hornblende. Granites from both areas might be formed from different sources with different degree of melting for grey, grayish green and pink granites.

Keywords: A-type granite, anorogenic, Malani igneous suite, Khanak and Devsar

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Authors: Ghodratollah Rostami Paydar

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The Baba-Ali and Galali iron deposits are located in northwest Hamedan and the Iranian Sanandaj-Sirjan geological structural zone. The host rocks of these deposits are metavolcanosedimentary successions of Songhor stratigraphic series with permo-trriassic age. Field investigation, ore geometry, textures and structures and paragenetic sequence of minerals, all indicate that the ore minerals are crystallized in four stages: primary volcanosedimentary stage, secondary regional metamorphism with formation of ductile shear zones, contact metamorphism and metasomatism stage and the finally late hydrothermal mineralization within uplift and exposure. Totally 29 samples of sulfide, oxide-silicate and carbonate minerals of iron orees and gangue has been purified for stable isotope analysis. The isotope ratio data assure that occurrence of dynamothermal metamorphism in these areas typically involves a lengthy period of time, which results in a tendency toward isotopic homogenization specifically in O and H stable isotopes and showing the role of metamorphic waters in mineralization process. Measurement of δ34S (CDT) in first generation of pyrite is higher than another ones, so it confirms the volcanogenic origin of primary iron mineralization. δ13C data measurements in Galali carbonate country rocks show a marine origin. δ18O in magnetite and skarn forming silicates, δ18O and δ13C in limestone and skarn calcite and δ34S in sulphides are all consistent with the interaction of a magmatic-equilibrated fluid with Galali limestone, and a dominantly magmatic source for S. All these data imply skarn formation and mineralisation in a magmatic-hydrothermal system that maintained high salinity to relatively late stages resulting in the formation of the regional Na metasomatic alteration halo. Late stage hydrothermal quartz-calcite veinlets are important for gold mineralization, but the economic evaluation is required to detailed geochemical studies.

Keywords: iron, polygenetic, stable isotope, BabaAli, Galali

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Authors: C. G. Mendez-Garcia, E. T. Romero-Guzman, H. Hernandez-Mendoza, C. Solis, E. Chavez-Lomeli, E. Chamizo, R. Garcia-Tenorio

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Plutonium is present in different concentrations in the environment and biological samples related to nuclear weapons testing, nuclear waste recycling and accidental discharges of nuclear plants. This radioisotope is considered the most radiotoxic substance, particularly when it enters the human body through inhalation of powders insoluble or aerosols. This is the main reason of the determination of the concentration of this radioisotope in the atmosphere. Besides that, the isotopic ratio of ²⁴⁰Pu/²³⁹Pu provides information about the origin of the source. PM₂.₅ sampling was carried out in the Metropolitan Zone of the Valley of Mexico (MZVM) from February 18th to March 17th in 2015 on quartz filter. There have been significant developments recently due to the establishment of new methods for sample preparation and accurate measurement to detect ultra trace levels as the plutonium is found in the environment. The accelerator mass spectrometry (AMS) is a technique that allows measuring levels of detection around of femtograms (10-15 g). The AMS determinations include the chemical isolation of Pu. The Pu separation involved an acidic digestion and a radiochemical purification using an anion exchange resin. Finally, the source is prepared, when Pu is pressed in the corresponding cathodes. According to the author's knowledge on these aerosols showed variations on the ²³⁵U/²³⁸U ratio of the natural value, suggesting that could be an anthropogenic source altering it. The determination of the concentration of the isotopes of Pu can be a useful tool in order the clarify this presence in the atmosphere. The first results showed a mean value of activity concentration of ²³⁹Pu of 280 nBq m⁻³ thus the ²⁴⁰Pu/²³⁹Pu was 0.025 corresponding to the weapon production source; these results corroborate that there is an anthropogenic influence that is increasing the concentration of radioactive material in PM₂.₅. According to the author's knowledge in Total Suspended Particles (TSP) have been reported activity concentrations of ²³⁹⁺²⁴⁰Pu around few tens of nBq m⁻³ and 0.17 of ²⁴⁰Pu/²³⁹Pu ratios. The preliminary results in MZVM show high activity concentrations of isotopes of Pu (40 and 700 nBq m⁻³) and low ²⁴⁰Pu/²³⁹Pu ratio than reported. These results are in the order of the activity concentrations of Pu in weapons-grade of high purity.

Keywords: aerosols, fallout, mass spectrometry, radiochemistry, tracer, ²⁴⁰Pu/²³⁹Pu ratio

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Authors: Mohamed Hrouda

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The Principal Component Analysis (PCA) was performed on a dataset comprising 41 biomarker concentrations from twenty-three core source rocks samples and seven oil samples from different location, with the objective of establishing the major sources of variance within the steranes, tricyclic terpanes, hopanes, and triaromatic steroid. This type of analysis can be used as an aid when deciding which molecular biomarker maturity, source facies or depositional environment parameters should be plotted, because the principal component loadings plots tend to extract the biomarker variables related to maturity, source facies or depositional environment controls. Facies characterization of the source rock samples separate the Silurian and Devonian source rock samples into three groups. Maturity evaluation of source rock samples based on biomarker and aromatic hydrocarbon distributions indicates that not all the samples are strongly affected by maturity, the Upper Devonian samples from wells located in the northern part of the basin are immature, whereas the other samples which have been selected from the Lower Silurian are mature and have reached the main stage of the oil window, the Lower Silurian source rock strata revealed a trend of increasing maturity towards the south and southwestern part of Ghadames Basin. Most of the facies-based parameters employed in this project using biomarker distributions clearly separate the oil samples into three groups. Group I contain oil samples from wells within Al-Wafa oil field Located in the south western part of the basin, Group II contains oil samples collected from Al-Hamada oil field complex in the south and the third group contains oil samples collected from oil fields located in the north

Keywords: Ghadamis basin, geochemistry, silurian, devonian

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Authors: Silvano Salvador, Maryam Zarrinderakht, Alan Martin

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Open pits, which are the result of mining, are filled by water over time until the water reaches the elevation of the local water table and generates mine pit lakes. There are several specific regulations about the water quality of pit lakes, and mining operations should keep the quality of groundwater above pre-defined standards. Therefore, an accurate, acceptable numerical model predicting pit lakes’ water balance and water quality is needed in advance of mine excavation. We carry on analyzing and developing the model introduced by Crusius, Dunbar, et al. (2002) for pit lakes. This model, called “PitMod”, simulates the physical and geochemical evolution of pit lakes over time scales ranging from a few months up to a century or more. Here, a lake is approximated as one-dimensional, horizontally averaged vertical layers. PitMod calculates the time-dependent vertical distribution of physical and geochemical pit lake properties, like temperature, salinity, conductivity, pH, trace metals, and dissolved oxygen, within each model layer. This model considers the effect of pit morphology, climate data, multiple surface and subsurface (groundwater) inflows/outflows, precipitation/evaporation, surface ice formation/melting, vertical mixing due to surface wind stress, convection, background turbulence and equilibrium geochemistry using PHREEQC and linking that to the geochemical reactions. PitMod, which is used and validated in over 50 mines projects since 2002, incorporates physical processes like those found in other lake models such as DYRESM (Imerito 2007). However, unlike DYRESM PitMod also includes geochemical processes, pit wall runoff, and other effects. In addition, PitMod is actively under development and can be customized as required for a particular site.

Keywords: pit lakes, mining, modeling, hydrology

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Authors: Gayathri Devi V, Aravamudan Kannan, Amit Sircar

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In the inner fuel cycle system of a nuclear fusion reactor, the Hydrogen Isotopes Removal System (HIRS) plays a pivoted role. It enables the effective extraction of the hydrogen isotopes from the breeder purge gas which helps to maintain the tritium breeding ratio and sustain the fusion reaction. One of the components of HIRS, Cryogenic Molecular Sieve Bed (CMSB) columns with zeolites adsorbents are considered for the physisorption of hydrogen isotopes at 1 bar and 77 K. Even though zeolites have good thermal stability and reduced activation properties making them ideal for use in nuclear reactor applications, their modest capacity for hydrogen isotopes adsorption is a cause of concern. In order to enhance the adsorbent capacity in an informed manner, it is helpful to understand the adsorption phenomena at the quantum electronic structure level. Physicochemical modifications of the adsorbent material enhances the adsorption capacity through the incorporation of active sites. This may be accomplished through the incorporation of suitable metal ions in the zeolite framework. In this work, molecular hydrogen isotopes adsorption on the active sites of functionalized zeolites are investigated in detail using Density Functional Theory (DFT) study. This involves the utilization of hybrid Generalized Gradient Approximation (GGA) with dispersion correction to account for the exchange and correlation functional of DFT. The electronic energies, adsorption enthalpy, adsorption free energy, Highest Occupied Molecular Orbital (HOMO), Lowest Unoccupied Molecular Orbital (LUMO) energies are computed on the stable 8T zeolite clusters as well as the periodic structure functionalized with different active sites. The characteristics of the dihydrogen bond with the active metal sites and the isotopic effects are also studied in detail. Validation studies with DFT will also be presented for adsorption of hydrogen on metal ion functionalized zeolites. The ab-inito screening analysis gave insights regarding the mechanism of hydrogen interaction with the zeolites under study and also the effect of the metal ion on adsorption. This detailed study provides guidelines for selection of the appropriate metal ions that may be incorporated in the zeolites framework for effective adsorption of hydrogen isotopes in the HIRS.

Keywords: adsorption enthalpy, functionalized zeolites, hydrogen isotopes, nuclear fusion, physisorption

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Authors: Milad Mirzaei Aminiyan, Abdolreza Akhgar, Farzad Mirzaei Aminiyan

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Water quality is the critical factor that influence on human health and quantity and quality of grain production in semi-humid and semi-arid area. Pistachio is a main crop that accounts for a considerable portion of Iranian agricultural exports. Give that pistachio tree is a tolerant type of tree to saline and alkaline soil and water conditions, but groundwater and irrigation water quality play important roles in main production this crop. For this purpose, 94 well water samples were taken from 25 wells and samples were analyzed. The results showed give that region’s geological, climatic characteristics, statistical analysis, and based on dominant cations and anions in well water samples (piper diagram); four main types of water were found: Na-Cl, K-Cl, Na-SO4, and K-SO4. It seems that most wells in terms of water quality (salinity and alkalinity) and based on Wilcox diagram have critical status. The analysis suggested that more than eighty-seven percentage of the well water samples have high values of EC that these values are higher than into critical limit EC value for irrigation water, which may be due to the sandy soils in this area. Most groundwater were relatively unsuitable for irrigation but it could be used by application of correct management such as removing and reducing the ion concentrations of Cl‾, SO42‾, Na+ and total hardness in groundwater and also the concentrated deep groundwater was required treatment to reduce the salinity and sodium hazard. Given that irrigation water quality in this area was relatively unsuitable for most agriculture production but pistachio tree was adapted to this area conditions. The integrated management of groundwater for irrigation is the way to solve water quality issues not only in Rafsanjan area, but also in other arid and semi-arid areas.

Keywords: groundwater quality, irrigation water quality, salinity, alkalinity, Rafsanjan plain, pistachio

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Authors: Morteza Taherinezhad, Ahmad Reza Rabbani, Morteza Asemani, Rudy Swennen

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Oil-oil correlation is one of the most important issues in geochemical studies that enables to classify oils genetically. Oil-oil correlation is generally estimated based on non-polar fractions of crude oil (e.g., saturate and aromatic compounds). Despite several advantages, the drawback of using these compounds is their susceptibility of being affected by secondary processes. The polar fraction of crude oil (e.g., asphaltenes) has similar characteristics to kerogen, and this structural similarity is preserved during migration, thermal maturation, biodegradation, and water washing. Therefore, these structural characteristics can be considered as a useful correlation parameter, and it can be concluded that asphaltenes from different reservoirs with the same genetic signatures have a similar origin. Hence in this contribution, an integrated study by using both non-polar and polar fractions of oil was performed to use the merits of both fractions. Therefore, five oil samples from oil fields in the Persian Gulf were studied. Structural characteristics of extracted asphaltenes were investigated by Fourier transform infrared (FTIR) spectroscopy. Graphs based on aliphatic and aromatic compounds (predominant compounds in asphaltenes structure) and sulphoxide and carbonyl functional groups (which are representatives of sulphur and oxygen abundance in asphaltenes) were used for comparison of asphaltenes structures in different samples. Non-polar fractions were analyzed by GC-MS. The study of asphaltenes showed the studied oil samples comprise two oil families with distinct genetic characteristics. The first oil family consists of Salman and Reshadat oil samples, and the second oil family consists of Resalat, Siri E, and Siri D oil samples. To validate our results, biomarker parameters were employed, and this approach completely confirmed previous results. Based on biomarker analyses, both oil families have a marine source rock, whereby marl and carbonate source rocks are the source rock for the first and the second oil family, respectively.

Keywords: biomarker, non-polar fraction, oil-oil correlation, petroleum geochemistry, polar fraction

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Authors: Rosendo Mendoza, María Carmen Hidalgo, María José Campos-Suñol, Julián Martínez, Javier Rey

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The impact of mining environmental liabilities and mine drainage on surface water quality has been investigated in the hydrographic basin of the La Carolina mining district (southern Spain). This abandoned mining district is characterized by the existence of important mineralizations of sulfoantimonides of Pb - Ag, and sulfides of Cu - Fe. All surface waters reach the main river of this mining area, the Grande River, which ends its course in the Rumblar reservoir. This waterbody is intended to supply 89,000 inhabitants, as well as irrigation and livestock. Therefore, the analysis and control of the metal(loid) concentration that exists in these surface waters is an important issue because of the potential pollution derived from metallic mining. A hydrogeochemical campaign consisting of 20 water sampling points was carried out in the hydrographic network of the Grande River, as well as two sampling points in the Rumbler reservoir and at the main tailings impoundment draining to the river. Although acid mine drainage (pH below 4) is discharged into the Grande river from some mine adits, the pH values in the river water are always neutral or slightly alkaline. This is mainly the result of a dilution process of the small volumes of mine waters by net alkaline waters of the river. However, during the dry season, the surface waters present high mineralization due to a constant discharge from the abandoned flooded mines and a decrease in the contribution of surface runoff. The concentrations of dissolved Cd and Pb in the water reach values of 2 and 81 µg/l, respectively, exceeding the limit established by the Environmental Quality Standard for surface water. In addition, the concentrations of dissolved As, Cu, and Pb in the waters of the Rumblar reservoir reached values of 10, 20, and 11 µg/l, respectively. These values are higher than the maximum allowable concentration for human consumption, a circumstance that is especially alarming.

Keywords: environmental quality, hydrogeochemistry, metal mining, surface water

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Authors: Temesgen Oljira, Olugbenga Akindeji Okunlola, Akinade Shadrach Olatunji, Dereje Ayalew, Bekele Ayele Bedada

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The Western Ethiopian Shield (WES) is underlain by volcano-sedimentary terranes, gneissic terranes, and ophiolitic rocks intruded by different granitoid bodies. For the past few years, Neoproterozoic rocks of the Megele area in the western part of the WES have been explored. Understanding the geology of the area and assessing the mineralized area's economic potential requires petrological, geochemical, and geological characterization of the Neoproterozoic granitoids and associated metavolcanic rocks. Thus, the geological, geochemical, and petrogenetic features of Neoproterozoic granitoids and associated metavolcanic rocks were elucidated using a combination of field mapping, petrological, and geochemical study. The Megele area is part of a low-grade volcano-sedimentary zone that has been intruded by mafic (dolerite dyke) and granitoid intrusions (granodiorite, diorite, granite gneiss). The granodiorite, associated diorite, and granite gneiss are calc-alkaline, peraluminous to slightly metaluminous, S-type granitoids formed in volcanic arc subduction (VAG) to syn-collisional (syn-COLD) tectonic setting by fractionation of LREE-enriched, HREE-depleted basaltic magma with considerable crustal input. While the metabasalt is sub-alkaline (tholeiitic), metaluminous bodies are generated at the mid-oceanic ridge tectonic setting by partially melting HREE-depleted and LREE-enriched basaltic magma. The reworking of sediment-loaded crustal blocks at depth in a subduction zone resulted in the production of S-type granitoids. This basaltic magma was supplied from an LREE-enriched, HREE-depleted mantle.

Keywords: fractional crystallization, geochemistry, Megele, petrogenesis, s-type granite

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Authors: Tahani Hallek, Dhaou Akrout, Riadh Ahmadi, Mabrouk Montacer

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The present work is an organic geochemical study of the Fahdene Formation outcrops at the Mahjouba region belonging to the Eastern part of the Kalaat Senan structure in northwestern Tunisia (the Kef-Tedjerouine area). The analytical study of the organic content of the samples collected, allowed us to point out that the Formation in question is characterized by an average to good oil potential. This fossilized organic matter has a mixed origin (type II and III), as indicated by the relatively high values of hydrogen index. This origin is confirmed by the C29 Steranes abundance and also by tricyclic terpanes C19/(C19+C23) and tetracyclic terpanes C24/(C24+C23) ratios, that suggest a marine environment of deposit with high plants contribution. We have demonstrated that the heterogeneity of organic matter between the marine aspect, confirmed by the presence of foraminifera, and the continental contribution, is the result of an episodic anomaly in relation to the sequential stratigraphy. Given that the study area is defined as an outer platform forming a transition zone between a stable continental domain to the south and a deep basin to the north, we have explained the continental contribution by successive forced regressions, having blocked the albian transgression, allowing the installation of the lowstand system tracts. This aspect is represented by the incised valleys filling, in direct contact with the pelagic and deep sea facies. Consequently, the Fahdene Formation, in the Kef-Tedjerouine area, consists of transgressive system tracts (TST) brutally truncated by extras of continental progradation; resulting in a mixed influence deposition having retained a heterogeneous organic material.

Keywords: molecular geochemistry, biomarkers, forced regression, deposit environment, mixed origin, Northern Tunisia

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