Evolution of groundwater chemistry in coastal aquifers of the south-eastern White Sea area (NW Russia) using 14C and 234U-238U dating

Малов, А. И.

doi:10.1016/j.scitotenv.2017.10.197

Cited by 21 publications

(14 citation statements)

References 37 publications

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“…The borehole GGS2-11 is located at the diamond deposit area with coordinates N65 • 20 48" E41 • 06 10" in the northwest of Russia and was drilled using a diamond drill bit (92 mm inner diameter, 112 mm outer diameter) and mud rotary methods to 101.2 m below the ground surface in July 2018. This core was selected because the sampled section traverses the aquifer of the Padun formation of the Vendian (Vpd) [27,28] which is of interest in the present study. Five samples were taken from the intervals of 66.7-66.…”

Section: Methodsmentioning

confidence: 99%

“…A volume of 500 mL of low mineralized water of Ca-Mg-Na-HCO 3 composition from the borehole had total dissolved solids (TDS) of 285 mg/L (see [28]) and was mixed with 50 g of core sample in centrifuge tubes and shaken for 1 h on an end-over-end shaker at room temperature. The boundary conditions when using low-mineralized fresh natural groundwater were as follows: temperature 20 • C, pH 7.7 and redox potential of 230 mV.…”

Section: Low Mineralized Fresh Natural Groundwatermentioning

confidence: 99%

“…A significantly higher content of uranium in them compared to red siltstones and sandstones shows a considerable variability in the permeability values of the aquifer, whereby they were away from the paths of groundwater filtration and have retained uranium. The green siltstones that were studied in the present work occur in the oxidative conditions of the aquifer which contains young fresh water [28]. They have high concentrations of uranium in readily soluble fractions and high 234 U: 238 U activity ratios.…”

Section: Evolution Of Uranium Isotopic Compositionsmentioning

confidence: 99%

“…For the study area, the following values of the parameters included in Equation (2) were previously obtained: C W = 5 µg/kg (from 23 definitions of uranium concentrations in fresh water in a Vendian aquifer [28]; n = 0.23 (from 52 determinations) and ρ m = 2.75 g/cm 3 (from 52 determinations); M s = 9.2065 [27].…”

Section: Retardation Factormentioning

confidence: 99%

“…In previous papers [27,28], the possibility of sharing uranium and carbon isotopes for dating groundwater has been discussed and the transport of uranium in solution is reasonably well described with a standard advection-dispersion-exchange formulation: ∆time = advection + weathering + recoil + desorption + production − precipitation − decay − adsorption [5][6][7]. Among the many factors, the main ones are t-Groundwater residence time in the aquifer (time), v-Groundwater flow velocity (advection), R d -Dissolution rate (weathering-precipitation), R-Retardation factor (sorption-desorption), p-Recoil loss factor (recoil + production), and λ 4 -Decay constants for 234 U (decay).…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 99%

Section: Low Mineralized Fresh Natural Groundwatermentioning

confidence: 99%

Section: Evolution Of Uranium Isotopic Compositionsmentioning

confidence: 99%

Section: Retardation Factormentioning

confidence: 99%