## 1 Introduction  
Geothermal springs are geological phenomena that occur in all parts of the world. They could be of volcanic or meteoric origin [1; 2] with uses ranging from power generation, industrial processing, agriculture, aquaculture, bottled water, the extraction of rare elements, and the use of thermophilic bacteria for industrial purposes, among others [1]. The socio-economic importance of geothermal springs has fluctuated over time, but over the past few decades, there has been an unprecedented resurgence of interest in this resource mainly due to a diversification in the application of the waters [1; 2; 3]. South Africa is richly endowed with geothermal springs with about 30% of these springs found in Limpopo Province [1]. The geothermal springs in the Province were classified according to the residing mountain--Waterberg Group, Soutpansberg Group, and Drakensberg Group [2]. For this study,the geothermal springs within the Soutpansberg Group (Basin and Karoo Trough) were investigated (Figure 1). These geothermal springs are associated with faults and impermeable dykes and are assumed to be of meteoric origin [1,3]. The optimal utilisation of geothermal springs is generally dependent upon their physical and chemical properties, and additionally, the geological formation found at the depth of origin. Individuals have utilised geothermal spring waters for different purposes for many years, ranging from bathing, therapeutic, religious, hygienic, and social purposes in several nations in the world [4,5]. [PERSON] [6] reported that environmental hydrogen and oxygen isotopes are ideal tracers of water systems since they are incorporated in the water molecules and therefore their behaviour and variations reflect the origin, the hydrological and geochemical processes that affect natural water bodies. Environmental isotopes with hydrochemical data are viable tools for understanding groundwater dynamics within the Soutpansberg basin because they provide critical information about sources of groundwater recharge, timing of recharge, water-rock interaction along flow paths, and mixing of distinct groundwater bodies [7]. This is despite the fact that groundwater is greatly affected by the geochemical processes occurring within the groundwater and interaction with the aquifer material leading to seasonal and spatial variations in the groundwater chemistry [8]. Hence, the geochemical characteristics of groundwater depend on the different geochemical processes and chemistry of water at the recharge area [9]. Some studies have been carried out on Limpopo geothermal springs ranging from hydrogeology, water quality, impacts on the surrounding soils and vegetation [10, 11, 12, 13, 14, 15], and recently, [PERSON] et al. [16, 17, 18]. None of these studies elucidated the isotopic signatures in relation to the hydrochemical parameters of the geothermal springs. There is a need to understand the groundwater system and chemical processes governing the resources such as sources, water types, and groundwater recharge, among others. The knowledge of the groundwater system and chemical processes will help to  
Figure 1: Hydrogeological map with Soutpansberg basin/Soutpansberg Karoo Trough located in the northern part of South Africa, showing the locations of geothermal springs. improve on the sustainability and development of the water resources within the locality. Already, some of the geothermal springs in Limpopo Province experience reduction in their yield and even dry up. For example, the hottest geothermal spring in the country--found at Siloam village--has dried up. Therefore, to avert these occurrences in the future, such studies have to be undertaken to improve knowledge of the hydrogeological systems of the geothermal springs for effective sustainability of the resources.