Using isotopic, hydrogeochemical-tracer and temperature data to characterize recharge and flow paths in a complex karst groundwater flow system in northern China

Sun, Ziyong; Ma, Rui; Wang, Yanxin; Ma, Teng; Liu, Yunde

Using isotopic, hydrogeochemical-tracer and temperature data to characterize recharge and flow paths in a complex karst groundwater flow system in northern China | Utilisation de traceurs isotopiques, hydrogéochimiques et de données de température pour caractériser la recharge et l’organisation des écoulements dans un système complexe karstique d’écoulements d’eau souterraine dans le nord de la Chine El uso de datos de isótopos, trazadores hidrogeoquímicos y temperatura para caracterizar la recarga y las trayectorias de flujo en un sistema complejo de flujo de agua subterránea kárstico en el norte de China 利用同位素水文地球化学示踪剂描述中国北方复杂岩溶地下水流系统中的补给和水流通道 Utilizando isótopos, traçador hidrogeoquímico e dados de temperatura para caracterizar a recarga e os caminhos de fluxo em um sistema cárstico de fluxo de águas subterrâneas complexo no norte da China

2016

Sun, Ziyong | Ma, Rui | Wang, Yanxin | Ma, Teng | Liu, Yunde

Isotopic and hydrogeochemical analysis, combined with temperature investigation, was conducted to characterize the flow system in the carbonate aquifer at Taiyuan, northern China. The previous division of karst subsystems in Taiyuan, i.e. the Xishan (XMK), Dongshan (DMK) and Beishan (BMK) mountain systems, were also examined. The measured δD, δ ¹⁸O and ³He/⁴He in water indicate that both thermal and cold groundwaters have a meteoric origin rather than deep crustal origin. Age dating using ³H and ¹⁴C shows that groundwater samples from discharge zones along faults located at the margin of mountains in the XMK and DMK are a mixture of paleometeoric thermal waters and younger cold waters from local flow systems. ¹⁴C data suggest that the average age was about 10,000 years and 4,000 years for thermal and cold groundwater in discharge zones, respectively. Based on the data of temperature, water solute chemical properties, ¹⁴C, δ ³⁴SSO₄, ⁸⁷Sr/⁸⁶Sr and δ ¹⁸O, different flow paths in the XMK and DMK were distinguished. Shallow groundwater passes through the upper Ordovician formations, producing younger waters at the discharge zone (low temperature and ionic concentration and enriched D and ¹⁸O). Deep groundwater flows through the lower Ordovician and Cambrian formations, producing older waters at the discharge zone (high ionic concentration and temperature and depleted D and ¹⁸O). At the margin of mountains, groundwater in deep systems flows vertically up along faults and mixes with groundwater from shallow flow systems. By contrast, only a single flow system through the entire Cambrian to Ordovician formations occurs in the BMK.

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