Hydrogeochemistry, geothermometry and genesis of the hot springs in the Simao Basin in southwestern China
Hydrogeochemistry, geothermometry and genesis of the hot springs in the Simao Basin in southwestern China
复制标题
西南思茅盆地温泉水文地球化学、地温测量及成因
DOI：
10.1155/2019/7046320
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发表时间：
--
期刊：
影响因子：
1.7
通讯作者：
Dongxue Huo
中科院分区：
文献类型：
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作者：
Yuqi Zhang;Xun Zhou;Haisheng Liu;Mingxiao Yu;Kuo Hai;Mengru Tan;Dongxue Huo
思茅盆地广泛发育渗透性较差的红层。然而，盆地中有100多个温泉，其中一些是温度不同的温泉。温泉蕴含着丰富的水文地球化学过程和地下水循环信息。在这项研究中，水化学和同位素分析和混合模型被用来检查的补给，热量和溶质的温泉，以更好地了解地下过程和形成机制的不同温泉盆地。思茅盆地有3种类型的泉：变质岩中的HCO 3-Na型泉，碳酸盐岩中的HCO 3-Ca（Mg）和Cl-HCO 3-Na-Ca型泉，红层中的Cl（SO 4）-SO 4（Cl）-HCO 3-Na（Ca）型泉。δ 2 H和δ 18 O数据表明，思茅盆地的温泉为大气降水成因。不一致溶解是影响泉水沃茨化学成分的主要过程。变质岩、碳酸盐岩和红层中温泉的水化学成分受钠长石风化作用和碳酸盐、石膏、硬石膏、岩盐溶解作用的影响。地热沃茨在上升过程中与浅层冷水沃茨混合，冷水混合率为58%~ 94%。由于混合的影响，用石英地质温度计计算的储层温度（51°C-127°C）被视为最低储层温度。采用固定-Al方法估计更可靠的储层温度（91°C-132°C）。思茅盆地温泉的形成机制是：地下水接受降水入渗补给，并经历深循环，在此过程中，地下水被热流加热，不协调地溶解地下矿物，沿沿着透水断裂带以温泉的形式出露。
In the Simao Basin in southwest China widely occur red beds of poor permeability. Nevertheless, more than 100 springs exist in the basin, some of which are hot springs with varying temperature. Hot springs contain abundant information on hydrogeochemical processes and groundwater circulation. In this study, hydrochemical and isotopic analyses and mixed models are used to examine the sources of recharge, heat, and solutes of the hot springs to better understand the subsurface processes and formation mechanisms of different hot springs in the basin. Three types of springs are found in the Simao Basin: springs of HCO3‐Na type occur in the metamorphic rocks, springs of HCO3‐Ca(Mg) and Cl‐HCO3‐Na‐Ca types in the carbonate rocks, and springs of Cl(SO4)‐SO4(Cl)‐HCO3‐Na(Ca) type in the red beds. Data ofδ2H andδ18O indicate that the hot springs in the Simao Basin are meteoric in origin. Incongruent dissolution is the dominant process affecting the chemical compositions of the spring waters. The hydrochemical constituents of the hot springs in the metamorphic rocks, carbonate rocks, and red beds are influenced by the weathering of albite and the dissolution of carbonate, gypsum, anhydrite, and halite. The geothermal waters are mixed with shallow cold waters in their ascending processes, and the mixing ratios of cold water range from 58% to 94%. Due to the effect of mixing, the reservoir temperatures (51°C‐127°C) calculated with the quartz geothermometer are regarded as the minimum reservoir temperatures. More reliable reservoir temperatures (91°C‐132°C) are estimated with the fixed‐Al method. The following mechanisms contribute to the formation of hot springs in the Simao Basin: the groundwater receives recharge from infiltration of precipitation and undergoes deep circulation, during which groundwater is heated by heat flow and incongruently dissolves the subsurface minerals and emerges in the form of hot springs along the permeable fracture or fault zones.