Issue |
E3S Web Conf.
Volume 98, 2019
16th International Symposium on Water-Rock Interaction (WRI-16) and 13th International Symposium on Applied Isotope Geochemistry (1st IAGC International Conference)
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Article Number | 07016 | |
Number of page(s) | 5 | |
Section | Geochemistry of Natural Waters: From Atmospheric Precipitations to Deep Brines | |
DOI | https://doi.org/10.1051/e3sconf/20199807016 | |
Published online | 07 June 2019 |
Evolution of groundwater chemistry in coastal aquifers of the Northern Dvina basin (NW Russia)
Federal Center for Integrated Arctic Research RAS, 23 Severnoy Dviny Emb., Arkhangelsk, 163061, Russia
* Corresponding author: malovai@yandex.ru
The specific objective of the study is to clarify the sources and characteristics of groundwater chemistry in coastal aquifers of the Northern Dvina basin. It has been established that the chemical composition of fresh water evolves in the direction (Ca-Mg-HCO3) - (Na-HCO3) - (Na-Cl). It is due to successive replacement of the process of calcite dissolution in the recharge area on the watershed i) by the process of hydrolysis of sodium aluminosilicates in the transit zone and ii) by the processes of mixing fresh water with salt water and brines, cation exchange of alkaline earth elements with alkaline elements and dissolution of gypsum near discharge areas at the seashore and in paleovalleys. In the brackish and salty waters the Na/Ca ratio is reduced to 1-4. This indicates that in the aquifers there are other sources of Ca, in addition to the dissolution of gypsum. The most probable process is the hydrolysis of Ca-aluminosilicates, which indicates a significant time of water-rock interaction. The “brackish1” water with TDS 5-6 g·L-1, is particularly distinguished by the degree of modification due to water-rock interaction.
© The Authors, published by EDP Sciences, 2019
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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