scholarly journals Behavior of the 238U, 235U, and 234U isotopes at weathering of volcanic rocks with u mineralization: a case study at the Tulukuevskoe deposit, Eastern Transbaikalia

2019 ◽  
Vol 27 (4) ◽  
pp. 446-467
Author(s):  
I. V. Chernyshev ◽  
V. N. Golubev ◽  
A. V. Chugaev ◽  
G. V. Mandzhieva ◽  
B. I. Gareev
Keyword(s):  
Aqueous Phase ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Volcanic Rocks ◽  
Mineral Phases ◽  
Icp Ms ◽  
Eastern Transbaikalia ◽  
Uranium Minerals ◽  
Fractionation Mechanism

The trend fractionation of the 238U and 235U isotopes and the extent of this process at the oxidative weathering of uranium minerals were evaluated by studying the variations in the U isotope composition of rocks, minerals, and fracture waters sampled in the quarry of the broadly known Tulukuevskoe uranium deposit in the Streltsovskoe ore field, eastern Transbaikalia. In the rock block in question, fine uranium minerals disseminated in the rocks were weathered under the effect of oxidizing fracture waters. Uranium isotope composition was measured in 22 water samples, eleven samples of the mineralized rocks, and eight uranium minerals. High-precision (±0.07‰, 2SD) measurements of the 238U/235U were carried out by MC-ICP-MS, using a 233U–236U double spike. The results involve the 238U/235U and 234U/238U ratios and the overall range of the δ238U variations determined in the rocks and waters (from –0.13 to –1.0‰ and from –0.22 to –0.59‰, respectively). Interaction between the waters and rocks induces U(IV) → U(VI) oxidation, U(VI) transfer into the aqueous phase, and 0.15–0.28‰ enrichment of U dissolved in the water in the 235U isotope. When the pitchblende is replaced by U(VI) minerals, the 238U and 235U isotopes also fractionate with ~0.3‰ enrichment of the younger U(VI) mineral phases in the light 235U isotope. The 238U/235U and 234U/238U ratios are proved to correlate, and hence, the fractionation of the 238U and 235U isotopes and the enrichment of the aqueous phase in the light 235U isotope proceed simultaneously with the well known shift in equilibrium the 238U–234U system with the accumulation of excess amounts of the 234U in the aqueous phase. Uranium leaching from uranium minerals, which is associated with the enrichment of the aqueous phase in excess amounts of the 234U isotope, can be viewed as a process that controls isotope fractionation in the 238U–235U system. This should be taken into account in describing the fractionation mechanism of the 238U and 235U isotopes at U(IV) → U(VI) oxidation. The fractionation of the 238U and 235U isotopes, which results in the isotopic "lightening" of U in the aqueous phase, largely controlled the complicated distribution pattern of the 238U/235U ratio in the quarry. In addition to isotope fractionation, this distribution was likely also affected by isotope exchange between uranium dissolved in the water and uranium in the finely dispersed minerals. The isotopically light uranium of the water could participate in forming U(VI) minerals at lower levels of the quarry.

Behavior of the 238U, 235U, and 234U Isotopes at Weathering of Volcanic Rocks with U Mineralization: A Case Study at the Tulukuevskoe Deposit, Eastern Transbaikalia

Petrology ◽  
2019 ◽  
Vol 27 (4) ◽  
pp. 407-424
Author(s):  
I. V. Chernyshev ◽  
V. N. Golubev ◽  
A. V. Chugaev ◽  
G. V. Mandzhieva ◽  
B. I. Gareev
Keyword(s):  
Volcanic Rocks ◽  
Eastern Transbaikalia

New data on microelement and isotope composition of thermal springs in Tajikistan

2018 ◽  
pp. 109-116
Author(s):  
T. A. Kireeva ◽  
F. S. Salikhov ◽  
A. Y. Bychkov ◽  
N. A. Kharitonova ◽  
A. V. Romashkina
Keyword(s):  
Isotope Fractionation ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Tien Shan ◽  
Thermal Springs ◽  
Thermal Waters ◽  
Water Line ◽  
Icp Ms ◽  
Mountain Systems ◽  
Subsurface Temperatures

This article provides detailed information about the geological setting and the chemical composition of some thermal springs (Garm-Chashma, Firuza-MGU, Tandykul, Obigarm, Khojaоbigarm) located within the Pamirs and the Tien Shan mountain systems. This is the first report describing the micro components data for investigated springs obtained by the ICP-MS method. The calculated ratios of B:Cl, B:Br and Li:Rb:Cs allow to define the genesis of the studied thermal springs. New data on the contents of 18O and D indicate that the studied thermal waters are most likely meteoric, while a slight drift from the meteoric water line is the result of isotope fractionation in water-rock-gas processes. The estimated subsurface temperatures for these thermal waters vary from 136 °C to 240 °C based on the K:Na geothermometer.

scholarly journals Modeling Insights into Precipitation Deuterium Excess as an Indicator of Raindrop Evaporation in Lanzhou, China

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 193
Author(s):  
Fenli Chen ◽  
Mingjun Zhang ◽  
Athanassios A. Argiriou ◽  
Shengjie Wang ◽  
Qian Ma ◽  
...  
Keyword(s):  
Arid Region ◽  
Quantitative Methods ◽  
Isotope Composition ◽  
Sampling Site ◽  
Western China ◽  
Cloud Base ◽  
Deuterium Excess ◽  
Semi Arid Region ◽  
Semi Arid

The deuterium excess in precipitation is an effective indicator to assess the existence of sub-cloud evaporation of raindrops. Based on the synchronous measurements of stable isotopes of hydrogen and oxygen (δ2H and δ18O) in precipitation for several sites in Lanzhou, western China, spanning for approximately four years, the variations of deuterium excess between the ground and the cloud base are evaluated by using a one-box Stewart model. The deuterium excess difference below the cloud base during summer (−17.82‰ in Anning, −11.76‰ in Yuzhong, −21.18‰ in Gaolan and −12.41‰ in Yongdeng) is greater than that in other seasons, and difference in winter is weak due to the low temperature. The variations of deuterium excess in precipitation due to below-cloud evaporation are examined for each sampling site and year. The results are useful to understand the modification of raindrop isotope composition below the cloud base at a city scale, and the quantitative methods provide a case study for a semi-arid region at the monsoon margin.

scholarly journals Triple Isotope Fractionation Exponents of Elements Measured by MC-ICP-MS—An Example of Mg

2019 ◽  
Vol 91 (22) ◽  
pp. 14314-14322 ◽  
Author(s):  
Michael Tatzel ◽  
Jochen Vogl ◽  
Martin Rosner ◽  
Michael J. Henehan ◽  
Thomas Tütken
Keyword(s):  
Isotope Fractionation ◽  
Icp Ms

scholarly journals Wine origin authentication linked to terroir – wine fingerprint

2019 ◽  
Vol 15 ◽  
pp. 02033
Author(s):  
B. Gabel
Keyword(s):  
Pore Water ◽  
Isotope Composition ◽  
Food Product ◽  
Isotopic Signature ◽  
Original Method ◽  
Economic Problem ◽  
Red Wines ◽  
Table Grapes ◽  
Mineral Phases

Global wine and alcohol trade faces a serious economic problem linked to counterfeiting of these commodities. Recently applied authentication methods and techniques pose more difficulties for counterfeiters but they are apparently not effective once we consider economical losses identified by EU legal authorities. The presented solution links isotopic characteristics of the soil, plant, technological intermediate product and the final food product (wine, grapes) on the basis of 87Sr/86Sr isotopes ratios. For the isotopic signature of wines, the average isotope composition of the substrate cannot be a reliable indicator. Only the isotopic composition of pore water can, as it leaches various mineral phases at different stages and passes into vine root system. Instead of complicated sampling of pore water, an original method of preparing and processing soil samples and consequently must & wine samples was developed. Based on both, soil and biological material analysis, we can unquestionably determine not only geographical but also regional and local authenticity of the wine. Determination of red wines isotopic signature is more straightforward process in comparison to white wines, because of technologically different processing of grapes. That is the reason why, in case of white vines, the 87Sr/86Sr ratio of bentonites (natural purifier and absorbent useful in the process of winemaking) must also be taken into consideration. Results of analyses of Slovak wines from geographically diverse regions as well as from sites in close-by distances have clearly established reliability of presented concept, in which the soil is linked to the plant and to the final food product (wine or table grapes).

Geochemistry and Isotope Composition of Paleoproterozoic Granites and Felsic Volcanics of the Elash Graben: Evidence of the Heterogeneity of the Early Precambrian Crust

2021 ◽  
Vol 62 (10) ◽  
pp. 1175-1187
Author(s):  
A.D. Nozhkin ◽  
O.M. Turkina ◽  
K.A. Savko
Keyword(s):  
Isotope Composition ◽  
Volcanic Rocks ◽  
Rare Metal ◽  
Temporal Association ◽  
Metal Deposit ◽  
Wide Range ◽  
Rare Metal Deposit ◽  
Geochronological Study ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Abstract —The paper presents results of a petrogeochemical and isotope–geochronological study of the granite–leucogranite association of the Pavlov massif and felsic volcanics from the Elash graben (Biryusa block, southwest of the Siberian craton). A characteristic feature of the granite–leucogranites is their spatial and temporal association with vein aplites and pegmatites of the East Sayan rare-metal province. The U–Pb age of zircon from granites of the Pavlov massif (1852 ± 5 Ma) is close to the age of the pegmatites of the Vishnyakovskoe rare-metal deposit (1838 ± 3 Ma). The predominant biotite porphyritic granites and leucogranites of the Pavlov massif show variable alkali ratios (K2O/Na2O = 1.1–2.3) and ferroan (Fe*) index and a peraluminous composition; they are comparable with S-granites. The studied rhyolites of the Tagul River (SiO2 = 71–76%) show a low ferroan index, a high K2O/Na2O ratio (1.6–4.0), low (La/Yb)n values (4.3–10.5), and a clear Eu minimum (Eu/Eu* = 0.3–0.5); they are similar to highly fractionated I-granites. All coeval late Paleoproterozoic (1.88–1.85 Ga) granites and felsic volcanics of the Elash graben have distinct differences in composition, especially in the ferroan index and HREE contents, owing to variations in the source composition and melting conditions during their formation at postcollisions extension. The wide range of the isotope parameters of granites and felsic volcanic rocks (εNd from +2.0 to –3.7) and zircons (εHf from +3.0 to +0.8, granites of the Toporok massif) indicates the heterogeneity of the crustal basement of the Elash graben, which formed both in the Archean and in the Paleoproterozoic.

Lithogeochemical characteristics of metasandstones of the Chetlas series (Chetlassky Kamen, Middle Timan)

2021 ◽  
pp. 3-12
Author(s):  
N. Y. Nikulova ◽  
◽  
O. V. Udoratina ◽  
I. V. Kozyreva
Keyword(s):  
Inductively Coupled Plasma ◽  
Volcanic Rocks ◽  
Rare Metal ◽  
Weathering Crust ◽  
Terrigenous Material ◽  
Inductively Coupled ◽  
Coastal Marine ◽  
Icp Ms ◽  
Middle Timan ◽  
Destruction Of Rocks

The lithological and geochemical features of the metasandstones of the Svetlinskaya and Vizingskaya formations of the Middle Late Riphean Chetlas series in the Middle Timan, which are a substrate of rare-metal-rare-earth mineralization in several ore occurrences of the Kosyus ore cluster, have been investigated. The interpretation of the results of traditional weight chemical and mass spectrometric inductively coupled plasma (ICP MS) analyses allowed us to identify differences in the material composition of metapesanics, mainly due to changes in the degree of sedimentation maturity of terrigenous material coming from the demolition areas. The composition of metasandstones in various ratios includes both weakly weathered products of destruction of volcanic rocks of intermediate/basic composition, and altered, including under conditions of the weathering crust, metaterrigenous formations. The accumulation of sediments took place in a shallow coastal-marine environment with changing hydrodynamics, which affected the rate of destruction of rocks in paleo-catchments.

Application of LA-ICP-MS trace-element analysis for precious metal deportment: a case study of the Kevitsa mine, Finland

2017 ◽  
Vol 29 (4) ◽  
pp. 635-644 ◽  
Author(s):  
Louis J Cabri ◽  
Michelle Kelvin ◽  
Zhaoping Yang ◽  
Simon E Jackson ◽  
Okan Altun
Keyword(s):  
Trace Element ◽  
Precious Metal ◽  
Trace Element Analysis ◽  
Element Analysis ◽  
Icp Ms

scholarly journals Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

2015 ◽  
Vol 15 (12) ◽  
pp. 6867-6877 ◽  
Author(s):  
S. J. Allin ◽  
J. C. Laube ◽  
E. Witrant ◽  
J. Kaiser ◽  
E. McKenna ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Isotope Composition ◽  
Stratospheric Ozone ◽  
Standard Uncertainty ◽  
Gas Chromatography Mass Spectrometry ◽  
Sources And Sinks ◽  
Chlorine Isotope ◽  
Tropospheric Measurements ◽  
Single Detector

Abstract. The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010a), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (ϵapp) for mid- and high-latitude stratospheric samples are respectively −2.4 (0.5) and −2.3 (0.4) ‰ for CFC-11, −12.2 (1.6) and −6.8 (0.8) ‰ for CFC-12 and −3.5 (1.5) and −3.3 (1.2) ‰ for CFC-113, where the number in parentheses is the numerical value of the standard uncertainty expressed in per mil. Assuming a constant isotope composition of emissions, we calculate the expected trends in the tropospheric isotope signature of these gases based on their stratospheric 37Cl enrichment and stratosphere–troposphere exchange. We compare these projections to the long-term δ (37Cl) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978–2010) and tropospheric firn air samples from Greenland (North Greenland Eemian Ice Drilling (NEEM) site) and Antarctica (Fletcher Promontory site). From 1970 to the present day, projected trends agree with tropospheric measurements, suggesting that within analytical uncertainties, a constant average emission isotope delta (δ) is a compatible scenario. The measurement uncertainty is too high to determine whether the average emission isotope δ has been affected by changes in CFC manufacturing processes or not. Our study increases the suite of trace gases amenable to direct isotope ratio measurements in small air volumes (approximately 200 mL), using a single-detector gas chromatography–mass spectrometry (GC–MS) system.

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