Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes
The hydrothermal system plays a crucial role in material and energy cycling between the lithosphere and hydrosphere. In general, seafloor hydrothermal systems are one of important Mg sinks, but the situation may not be the same as it is in terrestrial hydrothermal systems. In addition, the behavior...
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MDPI AG
2022-11-01
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| author | Jingying Yuan Haigang Cao Yuping Guo Xuegang Chen |
| author_facet | Jingying Yuan Haigang Cao Yuping Guo Xuegang Chen |
| author_sort | Jingying Yuan |
| collection | DOAJ |
| description | The hydrothermal system plays a crucial role in material and energy cycling between the lithosphere and hydrosphere. In general, seafloor hydrothermal systems are one of important Mg sinks, but the situation may not be the same as it is in terrestrial hydrothermal systems. In addition, the behavior of Mg isotopes during hydrothermal circulation is still unclear. Thus, in this study, we determined the Mg isotopic compositions of the hydrothermal fluids discharged in the Tengchong region to understand better the fate of Mg in the continental hydrothermal system. The δ<sup>2</sup>H and δ<sup>18</sup>O values of the Tengchong hydrothermal fluids indicate that the recharge water sources are primary from meteoric water and influenced by the evaporation process. In contrast, the subduction–related volcanic water input is limited, except in for the Rehai area. The Mg in most of the samples is contributed by percolated meteoric water. The measured δ<sup>26</sup>Mg values range from –0.969 to 0.173‰, which are enriched in light Mg compared to the volcanic rocks of Tengchong. Combined with the precipitation dissolution of carbonate, we calculated the δ<sup>26</sup>Mg value for the endmember fluid before precipitation, which shows that the process of carbonate precipitation changes the Mg isotope of the fluid, substantially. The Shiqiang (SQ) vent is unique among all of the samples, characterized by an extremely a high δ<sup>26</sup>Mg value and Mg concentration, and it is estimated that it could have been mixed with an upper crustal material. This also reveals the diversity of the hydrothermal fluid material sources in the subduction zone. |
| first_indexed | 2024-03-09T16:03:49Z |
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| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T16:03:49Z |
| publishDate | 2022-11-01 |
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| spelling | doaj.art-08554dfe474548f08bae4dac16a0d68a2023-11-24T16:50:37ZengMDPI AGMinerals2075-163X2022-11-011212149010.3390/min12121490Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg IsotopesJingying Yuan0Haigang Cao1Yuping Guo2Xuegang Chen3Ocean College, Zhejiang University, Zhoushan 316021, ChinaOcean College, Zhejiang University, Zhoushan 316021, ChinaOcean College, Zhejiang University, Zhoushan 316021, ChinaOcean College, Zhejiang University, Zhoushan 316021, ChinaThe hydrothermal system plays a crucial role in material and energy cycling between the lithosphere and hydrosphere. In general, seafloor hydrothermal systems are one of important Mg sinks, but the situation may not be the same as it is in terrestrial hydrothermal systems. In addition, the behavior of Mg isotopes during hydrothermal circulation is still unclear. Thus, in this study, we determined the Mg isotopic compositions of the hydrothermal fluids discharged in the Tengchong region to understand better the fate of Mg in the continental hydrothermal system. The δ<sup>2</sup>H and δ<sup>18</sup>O values of the Tengchong hydrothermal fluids indicate that the recharge water sources are primary from meteoric water and influenced by the evaporation process. In contrast, the subduction–related volcanic water input is limited, except in for the Rehai area. The Mg in most of the samples is contributed by percolated meteoric water. The measured δ<sup>26</sup>Mg values range from –0.969 to 0.173‰, which are enriched in light Mg compared to the volcanic rocks of Tengchong. Combined with the precipitation dissolution of carbonate, we calculated the δ<sup>26</sup>Mg value for the endmember fluid before precipitation, which shows that the process of carbonate precipitation changes the Mg isotope of the fluid, substantially. The Shiqiang (SQ) vent is unique among all of the samples, characterized by an extremely a high δ<sup>26</sup>Mg value and Mg concentration, and it is estimated that it could have been mixed with an upper crustal material. This also reveals the diversity of the hydrothermal fluid material sources in the subduction zone.https://www.mdpi.com/2075-163X/12/12/1490hydrothermal fluidmagnesium isotopehydrogen and oxygen isotopesTengchongsubduction zone |
| spellingShingle | Jingying Yuan Haigang Cao Yuping Guo Xuegang Chen Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes Minerals hydrothermal fluid magnesium isotope hydrogen and oxygen isotopes Tengchong subduction zone |
| title | Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes |
| title_full | Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes |
| title_fullStr | Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes |
| title_full_unstemmed | Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes |
| title_short | Source and Evolution of Subduction–Related Hot Springs Discharged in Tengchong Geothermal Field, Southwest China: Constrained by Stable H, O, and Mg Isotopes |
| title_sort | source and evolution of subduction related hot springs discharged in tengchong geothermal field southwest china constrained by stable h o and mg isotopes |
| topic | hydrothermal fluid magnesium isotope hydrogen and oxygen isotopes Tengchong subduction zone |
| url | https://www.mdpi.com/2075-163X/12/12/1490 |
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