The formation of springs is vital for understanding the subsurface transport of substances and energy in groundwater circulation. The Xiannvshan hot spring in the sandstone aquiclude near the Tongluoxia anticline in northeast Sichuan Basin of China is an up-flow spring discharging thermal groundwater from the underlying carbonate aquifer of the basin-anticline controlled type. This rarely-encountered up-flow spring neither issues directly from an aquifer, nor is controlled by a fault. The spring water is a very hard (hardness of 1050.069-1835.697 mg/L) and brackish hot spring water (TDS of 1650-2802 mg/L) of SO₄-Ca type and low temperature (34-38°C) issuing from a neutral and reduction subsurface environment, and is characterized by high ratios of γNa/γCl (average 1.354) and low γCa/γSO₄ (average 0.779), and high concentrations of Sr (7.62-17.183 mg/L) and F (1.87-8.15 mg/L). The ΣMREE of the hot water samples are greater than ΣLREE, and positive Eu and negative Ce anomalies exist. The dissolved constituents in the hot water are derived from the dissolution of calcite, dolomite, anhydrite, gypsum, polyhalite, halite, albite and K-feldspar and small amount of sylvite, epsomite, thenardite, langbeinite, celestite, barite, strontianite, magnesite, and fluorite in the carbonate aquifer, and the dissolution of sulphates prevails in the groundwater system. Hydrochemical similarity is found among the water samples from the two springs’ vents and the flowing borehole near the vents. Faster groundwater circulation caused by the flowing hot water borehole encourages the dissolution of minerals in the carbonate aquifer and slightly increases the TDS and temperature of the hot water from the flowing borehole.

泉水的形成对于理解地下水循环中物质和能量的地下传输至关重要。四川盆地东北部铜锣峡背斜砂岩隔水层仙女山温泉是从下伏的盆地背斜控制型碳酸盐岩含水层排热地下水的上流泉。这种很少遇到的上流泉既不是直接来自含水层，也不是由断层控制。泉水是一种非常坚硬（硬度为 1050.069-1835.697 mg/L）和微咸的 SO ₄ -Ca 型温泉水（TDS 为 1650-2802 mg/L），低温（34-38°C）来自中性和还原性地下环境，其特点是 γNa/γCl 比率高（平均 1.354）和低 γCa/γSO ₄（平均 0.779），以及高浓度的 Sr（7.62-17.183 mg/L）和 F（1.87-8.15 mg/L）。热水样品的ΣMREE大于ΣLREE，存在Eu正异常和Ce负异常。热水中的溶解成分来源于方解石、白云石、硬石膏、石膏、杂卤石、岩盐、钠长石和钾长石的溶解，以及少量钾盐、泻钠石、芒硝、海镁石、天青石、重晶石、菱锰矿、菱镁矿、和萤石在碳酸盐含水层，硫酸盐溶解在地下水系统中盛行。在两个泉水喷口和喷口附近流动钻孔的水样中发现了水化学相似性。