Numerical modelling of stable isotope (2H and 18O) transport in a hydro-geothermal system: Model development and implementation to the Guide Basin, China

Abstract

The groundwater tracers, deuterium ( 2 H or D) and oxygen-18 ( 18 O) are widely used to determine groundwater recharge origin, rate and temperature. Quantitative methods able to interpret δD and δ 18 O mobility in the subsurface, especially under high pressure and temperature conditions, remain the focus of ongoing research.Here we developed an isotope transport module as an add-on to the TOUGH2 simulator, which is able to describe the evolution of δD and δ 18 O in groundwater induced by advection, dispersion, water-rock interaction, and fractionation due to changes of water phase and density. The new model was tested by modelling the groundwater flow, temperature, fluid density and isotopic composition in a faulted, geothermal system in the Guide Basin, China. We found that the density-driven flow induced by temperature variations can lead to isotope fractionation between low-3 ] Highlights

The Stable Isotope Characteristics of Precipitation in the Middle East Highlighting the Link between the Köppen Climate Classifications and the δ18O and δ2H Values of Precipitation

“…Therefore, water resources in the Middle East should be studied and continuously monitored by accurate and reliable methods such as stable isotope techniques. These techniques can provide a comprehensive view on the crucial aspects of water resources such as origin, mixture, pollution, and evolution [3][4][5][6][7][8][9][10][11]. Precipitation is an important element of the water cycle and has a direct and quick effect on the quality and quantity of surface water and groundwater resources [12][13][14][15].…”

AI versus Classic Methods in Modelling Isotopic Separation Processes: Efficiency Comparison

“…The 18 O isotope separation cascade, which is used to obtain the experimental data, is presented in Figure 1 [25]. By using this separation cascade, the 18 O isotope separation is made through isotopic exchange in the system NO, NO 2 -H 2 O, HNO 3 .…”

“…The problem of modeling and controlling the separation processes is presented in several papers of the technical literature for different types of isotopes: [20][21][22][23][24]. The 18 O isotope is treated in many scientific articles by presenting its direct applications [9,[25][26][27]. In previous papers [28][29][30][31][32], some solutions for modeling and controlling the separation process for the 18 O isotope production are presented.…”

Karstic Groundwater Origin and Recharge Process in Zagros Region: Insights From Stable Isotopes (δ¹⁸O and Δ²H) Approach<strong> </strong>

“…The stable isotope techniques are among the most accurate and reliable methods to study water resources origin and evaluations (Clark and Fritz, 1997) and Ajeena, 2016;Ali et al, 2015;Bagheri et al, 2019;Cerar et al, 2018;Chitsazan et al, 2015;Jassas and Merker, 2015;Jiang et al, 2019;Parizi and Samani, 2014;Rafighdoust et al, 2015;Rezaei et al, 2013;Xu et al, 2018;Yeh et al, 2014) to investigate the groundwater origin, evaluation and groundwater/surface water interaction.…”