Raw data of Yichuan Basin

The dataset includes 21 atmospheric precipitation samples (AP), 24 surface water samples (SW), 60 phreatic water samples (PW), 11 confined water (CW), 10 spring water samples (SP), and 12 geothermal water samples (GW). Notably, owing to limitations in water resource management, only GW7 was obtained, whereas data for the other eleven geothermal samples were provided by the Luoyang Water Conservancy Bureau and Yichuan County Water Conservancy Bureau. Twenty-one precipitation samples (AP) were collected from September 2022 to October 2023, whereas the remaining samples were collected in the field from June to July 2023. All sampling procedures were standardized to ensure consistency and reliability of the water chemistry analysis. Samples were collected using a pump or bucket. Prior to sampling, the polyethylene sampling bottles were rinsed at least three times. The sample bottles were filled to the brim and immediately capped to prevent the formation of air bubbles. Each water sample was labeled and sealed immediately after sampling and sent to the laboratory for testing as soon as possible. Before analysis, all the water samples were filtered through a 0.45-μm membrane filter. The chemical components were analyzed at the Henan Provincial Rock and Mineral Testing Center. Both of pH and TDS were measured using a portable multiparameter water quality meter (MantaPlus 25), with 0.01 and 1 mg·L-1 accuracy, respectively. Cation (K+, Na+, Mg2+, Ca2+, Sr2+) and anion (Cl-, NO3-, SO42-) concentrations were determined using inductively coupled plasma mass spectrometry (Agilent 7900 ICPMS). HCO3- concentrations were measured by manual titration, and H2SiO3 was measured using a spectrophotometer (Cary 5000). All samples underwent anion and cation equilibrium testing with relative errors of 3%. δD and δ¹⁸O were measured by Beijing Taistrontium Test Technology Co., Ltd., using a water isotope analyzer (model Picarro-2140i). The standard high-precision method of wavelength scanning cavity ring-down spectroscopy was employed, wherein six needles were measured for each sample, and the average of the last three needles was taken as the test result. The standard deviations (STDEV) for δD and δ¹⁸O were ±1‰ and ±0.1‰, respectively. ⁸⁷Sr/⁸⁶Sr was conducted by the Institute of Hydrogeology and Environmental Geology of the Chinese Academy of Geological Sciences. The ⁸⁷Sr/⁸⁶Sr detection employed multi-collector plasma mass spectrometry, using the MC-ICP-MS (Neptune Plus) instrument, with an error margin of less than 0.00001.