{"title":"Identifying the genesis of hydrothermal activities in the Xiangcheng fault belt, southwestern China: Evidence from hydrochemistry and stable isotopes","authors":"","doi":"10.1016/j.oregeorev.2024.106221","DOIUrl":null,"url":null,"abstract":"<div><p>Regional faults are beneficial structures for the formation of hydrothermal activities and have thus become target areas for geothermal resource utilization. Numerous hydrothermal activities have been reported along the Xiangcheng fault belt, particularly concentrating in the Batang, Xiangcheng and Shangri-La areas. In this study, hydrochemistry and stable isotopes were used to identify the genesis of hydrothermal activities in the Xiangcheng fault belt. The pH values of the geothermal water in these regions gradually decreases in this order, while the total dissolved solids gradually increase. The δD and δ<sup>18</sup>O values indicate the geothermal waters are mainly originated from snowmelt water and meteoric water. The recharge elevation of geothermal waters in Batang, Xiangcheng, and Shangri-La was 4415–4904 m, 4585–5038 m, and 3673–3969 m, respectively. Most geothermal waters belong to the hydrochemical type HCO<sub>3</sub>-Na, however some Batang geothermal water is of the SO<sub>4</sub>·HCO<sub>3</sub>-Na type, influenced by deep geothermal gas, and some Shangri-La geothermal water is of HCO<sub>3</sub>-Ca·Na type, influenced by shallow cold water and dissolution of carbonate rocks. Correlations of major ions suggest that HCO<sub>3</sub>-Na type geothermal waters are determined by the dissolution of paragonite, K-feldspar and albite as well as positive ion exchange. According to Na-K-Mg triangle diagram and mineral saturation indices, the geothermal waters do not reach full equilibrium and are mixed with shallow cold. Geothermometers, including cationic and SiO<sub>2</sub>, and geochemical thermodynamic calculations indicate that the deep and shallow reservoir temperatures are 200–240 °C and 169–193 °C for the Batang area, 194–201 °C and 119–131 °C for the Xiangcheng area, and 156–178 °C and 100–109 °C for the Shangri-La area. Conceptual models of the genesis of hydrothermal activities in the Batang, Xiangcheng, and Shangri-La areas were constructed, respectively. CaCO<sub>3</sub> scaling is dominated in the study area. The hydrothermal activities of Batang and Xiangcheng areas with enriched deep materials and high reservoir temperatures are beneficial for rare-alkali metal (e.g., Li). The findings of this study provide a scientific basis for the development and utilization of geothermal resources in the high-temperature hydrothermal activity areas of western Sichuan.</p></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2000,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169136824003548/pdfft?md5=aa4d3c55d2abcea9abf96ccd4a2b5147&pid=1-s2.0-S0169136824003548-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ore Geology Reviews","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0169136824003548","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Regional faults are beneficial structures for the formation of hydrothermal activities and have thus become target areas for geothermal resource utilization. Numerous hydrothermal activities have been reported along the Xiangcheng fault belt, particularly concentrating in the Batang, Xiangcheng and Shangri-La areas. In this study, hydrochemistry and stable isotopes were used to identify the genesis of hydrothermal activities in the Xiangcheng fault belt. The pH values of the geothermal water in these regions gradually decreases in this order, while the total dissolved solids gradually increase. The δD and δ18O values indicate the geothermal waters are mainly originated from snowmelt water and meteoric water. The recharge elevation of geothermal waters in Batang, Xiangcheng, and Shangri-La was 4415–4904 m, 4585–5038 m, and 3673–3969 m, respectively. Most geothermal waters belong to the hydrochemical type HCO3-Na, however some Batang geothermal water is of the SO4·HCO3-Na type, influenced by deep geothermal gas, and some Shangri-La geothermal water is of HCO3-Ca·Na type, influenced by shallow cold water and dissolution of carbonate rocks. Correlations of major ions suggest that HCO3-Na type geothermal waters are determined by the dissolution of paragonite, K-feldspar and albite as well as positive ion exchange. According to Na-K-Mg triangle diagram and mineral saturation indices, the geothermal waters do not reach full equilibrium and are mixed with shallow cold. Geothermometers, including cationic and SiO2, and geochemical thermodynamic calculations indicate that the deep and shallow reservoir temperatures are 200–240 °C and 169–193 °C for the Batang area, 194–201 °C and 119–131 °C for the Xiangcheng area, and 156–178 °C and 100–109 °C for the Shangri-La area. Conceptual models of the genesis of hydrothermal activities in the Batang, Xiangcheng, and Shangri-La areas were constructed, respectively. CaCO3 scaling is dominated in the study area. The hydrothermal activities of Batang and Xiangcheng areas with enriched deep materials and high reservoir temperatures are beneficial for rare-alkali metal (e.g., Li). The findings of this study provide a scientific basis for the development and utilization of geothermal resources in the high-temperature hydrothermal activity areas of western Sichuan.
期刊介绍:
Ore Geology Reviews aims to familiarize all earth scientists with recent advances in a number of interconnected disciplines related to the study of, and search for, ore deposits. The reviews range from brief to longer contributions, but the journal preferentially publishes manuscripts that fill the niche between the commonly shorter journal articles and the comprehensive book coverages, and thus has a special appeal to many authors and readers.