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Guo, Qinghai ; Meng, Yue ; Planer-Friedrich, Britta:
An approach combining chlorine isotopes and hydrochemistry for identification of magmatic fluid-affected hydrothermal systems.
In: Journal of Hydrology.
Bd. 620, Part B
(2023)
.
- 129495.
ISSN 0022-1694
DOI: https://doi.org/10.1016/j.jhydrol.2023.129495
Abstract
Identification of hydrothermal systems affected by magmatic fluid input is relevant for geothermal energy development. Thus, an approach for identifying such systems based on chlorine isotope composition and auxiliary hydrochemical indices was proposed. The approach enabled us to distinguish Rehai, a magmatic hydrothermal area in the Tengchong volcanic region of China, from several other typical non-magmatic hydrothermal areas in Tengchong: Menglian, Shiqiang, and Jietou. The hot springs in the non-Rehai areas featured high δ37Cl values, reflecting an exclusive contribution of chlorine from hostrock leaching. By contrast, some hot springs with much lower δ37Cl values occurred in Rehai, all of which were nearly fully equilibrated waters with respect to reservoir hostrocks, rich in chloride and bromide. These springs should have the closest relationship with the fluids released from the underlying magma chamber. Notably, the potential reservoir processes that geothermal waters may undergo after receiving an input of magmatic fluids can further alter their chlorine isotope compositions to various degrees. Therefore, a deep understanding of these processes would help improve the use of the proposed approach based primarily on chlorine isotopes. Regarding Rehai, all the neutral to alkaline hot springs with δ37Cl values ranging from −0.44 ‰ to 0.31 ‰ evolved from a parent geothermal fluid that received an input of magmatic fluids—via adiabatic cooling, conductive cooling, mixing with low-temperature shallow groundwaters, or a combination of some of these processes. By contrast, the acidic Rehai hot springs with the highest δ37Cl values (up to 1.12 ‰) were essentially locally perched groundwaters heated by geothermal steam separated from underlying geothermal fluids upon their adiabatic cooling; thus, they were much less to do with the parent geothermal fluid than the neutral to alkaline springs were. Hence, only the neutral to alkaline Rehai hot springs not strongly affected by the mixing of shallow groundwaters and adiabatic cooling can reflect the chlorine isotope characteristics of intrusive magmatic fluids. Overall, chlorine isotope composition in combination with hydrochemistry has proven to be a robust tool for identifying a magmatic fluid-affected hydrothermal system.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Professur Umweltgeochemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Professur Umweltgeochemie > Professur Umweltgeochemie - Univ.-Prof. Dr. Britta Planer-Friedrich Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER |
| Titel an der UBT entstanden: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie |
| Eingestellt am: | 13 Apr 2023 07:45 |
| Letzte Änderung: | 13 Apr 2023 07:45 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/75895 |