Application of geological benchmarks for determining groundwater residence time in the aquifer based on uranium isotope data: Evidence from the Severnaya Dvina Basin

Малов, А. И.

doi:10.1134/s002449021303005x

Cited by 17 publications

(5 citation statements)

References 10 publications

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“…As detailed above in the different regional discussions, we do not identified any general correlation between the uranium trends and these broad scale characteristics of the aquifer. In particular, our data do not seem to corroborate the conclusions from recent studies correlating uranium concentrations and 234 U/ 238 U activity ratios with the 14 C activities and residence time (Kronfled et al, 1994;Malov, 2013;Malov et al, 2016), who found that groundwater with lower residence time, have enriched δ 18 O and δ 2 H values and lower 234 U/ 238 U ratios.…”

Section: Fig10contrasting

confidence: 99%

Uranium isotopes as tracers of groundwater evolution in the Complexe Terminal aquifer of southern Tunisia

Ammar

Deschamps

Chkir

et al. 2020

Quaternary International

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Section: Fig10contrasting

confidence: 99%

Uranium isotopes as tracers of groundwater evolution in the Complexe Terminal aquifer of southern Tunisia

Ammar

Deschamps

Chkir

et al. 2020

Quaternary International

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“…The place where 5 samples were taken for this study was the sea shelf of the Mikulinian (Eemian) Sea 115-130 ka ago and marine sediments up to 50-70 m thick contained a large amount (up to 10%) of organic residues of iodine-containing algae. Organic matter could have entered sediments of the upper part of the Vendian Formation during the diagenesis of marine precipitation [42].…”

Section: Evolution Of Uranium Isotopic Compositionsmentioning

confidence: 99%

Study of the Mobilization of Uranium Isotopes in a Sandstone Aquifer in Combination with Groundwater Data

Малов

Zykov

2019

Water

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This work is part of a research project that aims to develop a method for combined radiocarbon and uranium-isotope dating of groundwater. The specific objective of this study was to investigate the mobility of uranium isotopes in the various mineral phases of rocks of an aquifer of sandy-clay deposits of the Vendian in the northwest of Russia, for which a partial extraction procedure was used. Representative aliquots of each core sample were treated with various reagents: distilled water, low mineralized fresh natural groundwater, minopolycarboxylic acid chelating agent (0.05 M EDTA), 0.5M HCl, 15 M HNO 3 , as well as total digestion, and the U isotope data for each procedure are reported in this study. The following mineral phases of core samples were characterized: sorbed material, carbonate minerals, amorphous iron oxides, partially soluble aluminosilicates and crystalline iron oxides, totally digestible aluminosilicates and a clay/quartz resistate. Red-colored siltstones and sandstones were depleted in uranium in relatively readily soluble mineral phases. The concentration of sorbed uranium was established in the range 15.8 ± 2.1-30.5 ± 3.9 µg/kg and carbonate minerals contained even less uranium. For iron hydroxides and the most readily soluble aluminosilicates, uranium concentrations were in the range 168 ± 24-212 ± 28 µg/kg. The most insoluble fraction contained uranium in the range 1.65 ± 0.21-4.32 ± 0.45 mg/kg. In green-colored siltstones, the concentration of sorbed uranium was much higher in the range 106 ± 14-364 ± 43 µg/kg. Carbonate minerals and amorphous iron oxides contained uranium in the range 1.91 ± 0.21-2.34 ± 0.26 mg/kg. In aluminosilicates and a clay/quartz resistate, uranium concentrations were in the range 5.6 ± 0.5-16.8 ± 1.4 mg/kg. Elevated values of 234 U: 238 U activity ratio prevailed in the sorbed material and iron hydroxides. In aluminosilicates and clay/quartz resistate, the values decreased. This indicates the replacement of primary sedimentogenic uranium by secondary hydrogenic uranium sorbed on the surface of minerals and coprecipitation with iron hydroxides. The results obtained made it possible to carry out preliminary quantitative estimates of the retardation factor and recoil loss factor of uranium in the groundwater of siltstones and sandstones of the studied Vendian aquifer.

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“…Таблица 2. Возможные связи изотопного состава термальных вод с геохимическими процессами в водоносных горизонтах и климатическими изменениями (по [5][6] Некоторая добавка CO 2 может оставаться в воде в виде CO 2 (aq) без дальнейшей реакции с карбонатами с образованием бикарбоната. В этом случае снижается δ 13 С. Если весь CO 2 прореагировал с карбонатами, δ 13 С может остаться без изменения (5) Эффекты изменений климата и 14 C atm от плейстоцена к голоцену ↓ ↓ Изменения в геохимическом состоянии окружающей среды: Снижение δ 13 С почвенного CO 2 в связи с более теплым и влажным климатом, снижение 14 C atm Наши результаты: со снижением возраста воды от 13.9 ± 1.5 до 6.2 тысяч лет, оба 14 C 0 и δ 13 С снижаются ↓ ↓ * Изменения 14 C 0 и δ 13 С (↑: возрастание; ↓: снижение; →: без изменений).…”

Section: заключениеunclassified

“…Повышенное значение среднего отношения активностей изотопов 234 U/ 238 U в травертинах (5,2 ± 0,85) по сравнению с водами современных термальных источников (3,8 ± 0,58) подтверждает это предположение [5][6]. Однако этот процесс должен привести к увеличению δ 13 С. У нас же наблюдается снижение и 14 C 0 и δ 13 С (рис.…”

Section: Introductionunclassified

Evolution of Thermal Water Isotopic Composition in Connection With Geochemical Processes in Aquifers and Climatic Changes

Малов¹

2018

The Geological Evolution of the Water-Rock Interaction

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АННОТАЦИЯ: Данные о современной активности 14 С в травертинах гидротермальной системы использовались в сочетании с 230 Th/U датированием травертина для оценки 14 C TDIC в древней термальной воде во время осаждения травертина ( 14 C calc ) и для расчета исходной активности 14 C ( 14 C 0 ) в этой воде. Установлено что 14 C 0 и δ 13 С снизились в молодых водах по сравнению с древними. Это связывается с климатическими изменениями. Снижение δ 13 С почвенного CO 2 и уменьшение 14 C 0 были вызваны преимущественно более теплым и влажным климатом, разложением ископаемого органического вещества и снижением активности атмосферного радиоуглерода ( 14 C atm ). Возможно также повышение растворения карбонатов и увеличение углеродного обмена между DIC и почвенным CO 2 , в связи с таянием вечной мерзлоты.ABSTRACT: Data on modern 14С activity in the travertine formations of the Pymvashor hydrothermal system were used, in combination with 230Th/U dating of the travertine, to estimate the 14C contents of the TDIC in the ancient thermal water at the time of precipitation of the travertine (14Ccalc) and to calculate the initial 14C contents (14C0) in this water. The finding in this study is that both 14C0 and δ13С have decreased in young waters compared to the ancient waters. One could link changes in 14C0 and δ13C to climate change. Decrease in δ13С of soil CO2 and decrease in 14C0 was caused predominantly by warmer and wetter climate, decomposition of fossil organic matter, and decrease in 14Catm. There could be also increased dissolution of solid carbonate and increased carbon exchange between DIC and soil CO2, caused by thawing permafrost.

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Application of geological benchmarks for determining groundwater residence time in the aquifer based on uranium isotope data: Evidence from the Severnaya Dvina Basin

Cited by 17 publications

References 10 publications

Uranium isotopes as tracers of groundwater evolution in the Complexe Terminal aquifer of southern Tunisia

Uranium isotopes as tracers of groundwater evolution in the Complexe Terminal aquifer of southern Tunisia

Study of the Mobilization of Uranium Isotopes in a Sandstone Aquifer in Combination with Groundwater Data

Evolution of Thermal Water Isotopic Composition in Connection With Geochemical Processes in Aquifers and Climatic Changes

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