Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction
The sequential extraction procedure is used to reconstruct the processes of redistribution of uranium isotopes in the mineral phases of the aquifer of the Vendian sandy-argillaceous deposits developed in the coastal territory of the European North of Russia. This aquifer has large resources of drink...
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| Format: | Article |
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MDPI AG
2021-04-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/11/5/467 |
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| author | Alexander I. Malov Sergey B. Zykov Alexey S. Tyshov |
| author_facet | Alexander I. Malov Sergey B. Zykov Alexey S. Tyshov |
| author_sort | Alexander I. Malov |
| collection | DOAJ |
| description | The sequential extraction procedure is used to reconstruct the processes of redistribution of uranium isotopes in the mineral phases of the aquifer of the Vendian sandy-argillaceous deposits developed in the coastal territory of the European North of Russia. This aquifer has large resources of drinking and mineral groundwater which, however, are used in extremely limited quantities. This is due to the very complex nature of the hydrochemical conditions, and uranium-isotopic methods are used to clarify these conditions. The following mineral phases of core samples were characterized: adsorbed trace materials and carbonate minerals; ferrihydrate, amorphous minerals of Fe, Al and Si, and secondary U minerals; crystalline iron minerals; clay and some refractory minerals; and all remaining resistant minerals. The most resistant minerals, whose fraction ranges from 70.58 to 96.4%, have a minimum average uranium concentration of 0.47 ppm. This uranium is practically conserved in the rock, as a result of which the average ratio of its <sup>234</sup>U:<sup>238</sup>U isotopes is close to equilibrium. In the remaining fractions, uranium is redistributed by groundwater along their flow lines from recharge areas in watersheds to areas of discharge into river valleys. Its maximum concentration (12.89 ppm) measurement is carried out by coprecipitation with iron hydroxides, then the uranium is adsorbed and precipitated with carbonates (9.14 ppm). The average <sup>234</sup>U:<sup>238</sup>U is maximum in adsorbed trace materials and carbonate minerals (2.39 ± 0.36) and is close to that in fresh groundwater (2.8 ± 0.42). It is also increased in the amorphous minerals of Fe (1.53 ± 0.23). In general, there is a dependence of the <sup>234</sup>U:<sup>238</sup>U activity ratio in rock on the degree of participation of groundwater in the deposition of hydrogenic uranium isotopes into the cracks and pores of these rocks. The results obtained contribute to the refinement of such a parameter as the retardation factor, which is necessary for understanding the processes of migration and concentration of uranium in sedimentary basins. |
| first_indexed | 2024-03-10T11:50:56Z |
| format | Article |
| id | doaj.art-372cebe4d66e40628bde86c0262cc33c |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T11:50:56Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-372cebe4d66e40628bde86c0262cc33c2023-11-21T17:43:46ZengMDPI AGMinerals2075-163X2021-04-0111546710.3390/min11050467Distribution of Uranium Isotopes in Sandy Deposits by Sequential ExtractionAlexander I. Malov0Sergey B. Zykov1Alexey S. Tyshov2N. Laverov Federal Center for Integrated Arctic Research of Russian Academy of Sciences, 23 Severnoy Dviny Emb., 163061 Arkhangelsk, RussiaN. Laverov Federal Center for Integrated Arctic Research of Russian Academy of Sciences, 23 Severnoy Dviny Emb., 163061 Arkhangelsk, RussiaN. Laverov Federal Center for Integrated Arctic Research of Russian Academy of Sciences, 23 Severnoy Dviny Emb., 163061 Arkhangelsk, RussiaThe sequential extraction procedure is used to reconstruct the processes of redistribution of uranium isotopes in the mineral phases of the aquifer of the Vendian sandy-argillaceous deposits developed in the coastal territory of the European North of Russia. This aquifer has large resources of drinking and mineral groundwater which, however, are used in extremely limited quantities. This is due to the very complex nature of the hydrochemical conditions, and uranium-isotopic methods are used to clarify these conditions. The following mineral phases of core samples were characterized: adsorbed trace materials and carbonate minerals; ferrihydrate, amorphous minerals of Fe, Al and Si, and secondary U minerals; crystalline iron minerals; clay and some refractory minerals; and all remaining resistant minerals. The most resistant minerals, whose fraction ranges from 70.58 to 96.4%, have a minimum average uranium concentration of 0.47 ppm. This uranium is practically conserved in the rock, as a result of which the average ratio of its <sup>234</sup>U:<sup>238</sup>U isotopes is close to equilibrium. In the remaining fractions, uranium is redistributed by groundwater along their flow lines from recharge areas in watersheds to areas of discharge into river valleys. Its maximum concentration (12.89 ppm) measurement is carried out by coprecipitation with iron hydroxides, then the uranium is adsorbed and precipitated with carbonates (9.14 ppm). The average <sup>234</sup>U:<sup>238</sup>U is maximum in adsorbed trace materials and carbonate minerals (2.39 ± 0.36) and is close to that in fresh groundwater (2.8 ± 0.42). It is also increased in the amorphous minerals of Fe (1.53 ± 0.23). In general, there is a dependence of the <sup>234</sup>U:<sup>238</sup>U activity ratio in rock on the degree of participation of groundwater in the deposition of hydrogenic uranium isotopes into the cracks and pores of these rocks. The results obtained contribute to the refinement of such a parameter as the retardation factor, which is necessary for understanding the processes of migration and concentration of uranium in sedimentary basins.https://www.mdpi.com/2075-163X/11/5/467sequential extractionmineral phasesuraniummigrationdisequilibrium |
| spellingShingle | Alexander I. Malov Sergey B. Zykov Alexey S. Tyshov Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction Minerals sequential extraction mineral phases uranium migration disequilibrium |
| title | Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction |
| title_full | Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction |
| title_fullStr | Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction |
| title_full_unstemmed | Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction |
| title_short | Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction |
| title_sort | distribution of uranium isotopes in sandy deposits by sequential extraction |
| topic | sequential extraction mineral phases uranium migration disequilibrium |
| url | https://www.mdpi.com/2075-163X/11/5/467 |
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