Analysis of n( 87 Sr)/n( 86 Sr), δ 88 Sr/ 86 Sr SRM987 and elemental pattern to characterise groundwater and recharge of saline ponds in a clastic aquifer in East Austria

• Published in: Isotopes in environmental and health studies Vol. 55; no. 2; pp. 179 - 198
• Main Authors: Tchaikovsky, Anastassiya, Häusler, Hermann, Kralik, Martin, Zitek, Andreas, Irrgeher, Johanna, Prohaska, Thomas
• Format: Journal Article
• Language: English
• Published: England 01-05-2019
• Subjects: isotope geochemistry; non-traditional stable isotopes; Lake Neusiedl-Seewinkel Basin; Chemometrics; isotope fractionation; strontium
• ISSN: 1025-6016; 1477-2639
• DOI: 10.1080/10256016.2019.1577832

Elemental and isotopic pattern of n(
Sr)/n(
Sr) and δ
Sr/
Sr
were used to characterise groundwater and recharge of saline ponds in a clastic aquifer in East Austria. Therefore, shallow, artesian and thermal groundwaters of the investigated aquifer along with rainfall and rivers were analysed using (MC) ICP-MS. The n(
Sr)/n(
Sr) ratio and elemental pattern changed with aquifer depth as a result of progressing bedrock leaching and dissolution with increasing groundwater residence time. The n(
Sr)/n(
Sr) ratio of shallow groundwater below saline ponds of 0.71019 ± 0.00044 was significantly different from thermal groundwater of 0.71205 ± 0.00035 (U, k = 2). In contrast to previous theories, this result suggested no recharge of saline ponds by upwelling paleo-seawater. Isotope pattern deconvolution revealed that rainfall accounted to about 60% of the n(
Sr)/n(
Sr) ratio of shallow groundwater below saline ponds. The δ
Sr/
Sr
values of groundwater decreased from about 0.25 ‰ in most shallow, to predominantly negative values of about -0.24 ‰ in artesian groundwater. This result indicated leaching and dissolution of weathered minerals. In turn, the δ
Sr/
Sr
of deep thermal groundwater showed positive values of about 0.12 ‰, which suggested removal of
Sr from solution by carbonate precipitation. These results highlight the potential of δ
Sr/
Sr
signature as an additional geochemical tracer.