Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibe...Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibet,the Gudui geothermal field belongs to the Sangri-Cuona rift belt,also known as the Sangri-Cuona geothermal belt,and is representative of the non-volcanic geothermal systems in the Himalayas.In this study,oxygen-18 and deuterium isotope compositions as well as 87Sr/86Sr ratios of water samples collected from the Gudui geothermal field were characterized to understand the origin and mixing processes of the geothermal fluids at Gudui.Hydrogen and oxygen isotope plots show both,deep and shallow reservoirs in the Gudui geothermal field.Deep geothermal fluids are the mixing product of magmatic and infiltrating snow-melt water.Calculations show that the magma fluid component of the deep geothermal fluids account for about 21.10%-24.04%;magma fluids lay also be a contributing source of lithium.The linear relationship of the 87Sr/86Sr isotopic ratio versus the 1/Sr plot indicates that shallow geothermal fluids form from the mixing of deep geothermal fluids with cold groundwater.Using a binary mixing model with deep geothermal fluid and cold groundwater as two end-members,the nixing ratios of the latter in most surface hot springs samples were calculated to be between 5% and 10%.Combined with basic geological characteristics,hydrogen and oxygen isotope characteristics,strontium concentration,87Sr/(86)Sr ratios,and the binary mixing model,we infer the 6 th-Class Reservoirs Evolution Conceptual Model(6-CRECM) for the Gudui geothermal system.This model represents an idealized summary of the characteristics of the Gudui geothermal field based on our comprehensive understanding of the origin and mixing processes of the geothermal fluid in Gudui.This study may aid in identifying the geothermal and geochemical origin of the Gudui high-temperature hydrothermal systems in remote Tibet of China,whose potential for geother展开更多
古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场...古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场对比分析、水文地球化学及同位素分析、岩溶水资源评价等方法,详细论述了古堆-南梁泉域内岩溶水环境问题现状及其成因,并提出了泉源区生态修复与规划方案。结果表明:受气候变化与人类活动的叠加影响,系统内古堆泉、南梁泉、海头泉分别于1999年、1992年、2002年断流,2013-2021年区域地下水位平均下降速度达2.53 m/a;水化学、同位素分析结果指示了排泄区九原山附近松散岩类孔隙水越流补给量、三泉水库渗漏补给量对岩溶地下水的影响已不可忽略;泉域内岩溶水超Ⅲ类水水质标准样品占比由2014年的62.5%升高至2021年的81.25%;泉源区0.904 km 2范围可细分为核心保护区、水库蓄水区、一般保护区,应分区进行生态保护与修复规划。研究结果可为山西省超采区综合治理、古堆泉水生态修复与保护工作提供基础依据。展开更多
基金This work was financially supported by the China Geological Survey(Grant No.DD20160054)the National Natural Science Foundation of China(Grant No.U1407207)the National Key Research and Development Program of China(Grant No.2017YFC0602802).
文摘Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibet,the Gudui geothermal field belongs to the Sangri-Cuona rift belt,also known as the Sangri-Cuona geothermal belt,and is representative of the non-volcanic geothermal systems in the Himalayas.In this study,oxygen-18 and deuterium isotope compositions as well as 87Sr/86Sr ratios of water samples collected from the Gudui geothermal field were characterized to understand the origin and mixing processes of the geothermal fluids at Gudui.Hydrogen and oxygen isotope plots show both,deep and shallow reservoirs in the Gudui geothermal field.Deep geothermal fluids are the mixing product of magmatic and infiltrating snow-melt water.Calculations show that the magma fluid component of the deep geothermal fluids account for about 21.10%-24.04%;magma fluids lay also be a contributing source of lithium.The linear relationship of the 87Sr/86Sr isotopic ratio versus the 1/Sr plot indicates that shallow geothermal fluids form from the mixing of deep geothermal fluids with cold groundwater.Using a binary mixing model with deep geothermal fluid and cold groundwater as two end-members,the nixing ratios of the latter in most surface hot springs samples were calculated to be between 5% and 10%.Combined with basic geological characteristics,hydrogen and oxygen isotope characteristics,strontium concentration,87Sr/(86)Sr ratios,and the binary mixing model,we infer the 6 th-Class Reservoirs Evolution Conceptual Model(6-CRECM) for the Gudui geothermal system.This model represents an idealized summary of the characteristics of the Gudui geothermal field based on our comprehensive understanding of the origin and mixing processes of the geothermal fluid in Gudui.This study may aid in identifying the geothermal and geochemical origin of the Gudui high-temperature hydrothermal systems in remote Tibet of China,whose potential for geother
文摘古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场对比分析、水文地球化学及同位素分析、岩溶水资源评价等方法,详细论述了古堆-南梁泉域内岩溶水环境问题现状及其成因,并提出了泉源区生态修复与规划方案。结果表明:受气候变化与人类活动的叠加影响,系统内古堆泉、南梁泉、海头泉分别于1999年、1992年、2002年断流,2013-2021年区域地下水位平均下降速度达2.53 m/a;水化学、同位素分析结果指示了排泄区九原山附近松散岩类孔隙水越流补给量、三泉水库渗漏补给量对岩溶地下水的影响已不可忽略;泉域内岩溶水超Ⅲ类水水质标准样品占比由2014年的62.5%升高至2021年的81.25%;泉源区0.904 km 2范围可细分为核心保护区、水库蓄水区、一般保护区,应分区进行生态保护与修复规划。研究结果可为山西省超采区综合治理、古堆泉水生态修复与保护工作提供基础依据。
