Water sampling at springs that are a part of the Freeling Spring Group, South Australia, was used along with electrical resistivity imaging (ERI) data to evaluate the sources and pathways for groundwater to the springs and to find evidence of mixing between the Great Artesian Basin (GAB) aquifer system (Algebuckina Sandstone, Cadna-owie Formation and lateral equivalents) and waters from the adjacent mountain block basement (MB) aquifer. Five springs and a well were used to evaluate spring chemistry; multi-electrode resistivity data were collected along three orientations over the Freeling Spring site. The resistivity data indicate three independent electrically conductive curvilinear features connected to the spring. These features are evidence of mixing at the spring vent similar to what would be predicted from traditional hydraulic flownets. The chemistry of the spring water samples indicates that the water emanating from the Freeling Spring Group is a mixture of waters from both the GAB and the MB aquifers, supporting the geophysical evidence. The data suggest mixing occurs along a fracture in the body of the MB and porous media flow in the GAB beds, but the system is dominated by the GAB flow, which provides approximately 90% of the discharge. A partir d’un échantillonnage d’eau sur des sources appartenant au groupe des sources Freeling au sud de l’Australie, et de données d’imagerie de résistivité électrique (IRE) l’origine et les trajets souterrains de l’eau souterraine vers les sources ont été évalués, et le mélange des eaux du système aquifère du grand bassin artésien (GBA) (grès d’Algebuckina, formation de Cadna-owie et équivalents latéraux) avec celles de l’aquifère de socle montagneux voisin (SM) a été mis en évidence. Cinq sources et un puits ont été utilisés pour évaluer la chimie des sources; des données de résistivité multi-électrode ont été rassemblées le long de trois orientations au-dessus de l’emplacement des sources Freeling. Les données de résistivité indiquent trois directions conductrices curvilignes, électriquement indépendantes, connectées aux sources. Ces caractéristiques sont la preuve qu’un mélange s’effectue à l’émergence de la source comme cela pourrait être attendu d’un réseau d’écoulement hydraulique traditionnel. La chimie des échantillons d’eau des sources indique que l’eau émanant du groupe des sources de Freeling est un mélange des eaux du GBA et de celles des aquifères du SM, confirmant les éléments géophysiques. Les données suggèrent que le mélange se produit à partir d’une fracture dans la masse du SM et d’un écoulement en milieu poreux le long des lits du GBA, mais le système est dominé par l’écoulement dans le GBA, qui fournit approximativement 90% du débit. El muestreo de agua en manantiales que forman parte del Freeling Spring Group, South Australia, se utilizó junto con datos de imágenes de resistividad eléctrica (ERI) para evaluar las fuentes y las trayectorias de acceso de las aguas subterráneas a los manantiales y para encontrar evidencias de mezcla entre el sistema acuífero de la Great Artesian Basin (Algebuckina Sandstone, Cadna-owie Formation y equivalentes laterales) y las aguas del acuífero deL basamento adyacente en el bloque montañoso (MB). Se utilizaron cinco manantiales y un pozo para evaluar la química de los manantiales; los datos de resistividad de múltiples electrodos se recolectaron a lo largo de tres orientaciones sobre el sitio de Freeling Spring. Los datos de resistividad indican tres características curvilíneas conductoras de electricidad independientes conectadas al manantial. Estas características son evidencias de que la mezcla en el conducto del manantial es similar a la que se predeciría a partir de las tradicionales redes de flujo subterráneo. La química de las muestras de agua de manantial indica que el agua que emana del Freeling Spring Group es una mezcla de aguas de los acuíferos GAB y MB, que apoyan la evidencia geofísica. Los datos sugieren que la mezcla ocurre a lo largo de una fractura en el cuerpo del MB y el flujo de medios porosos en los estratos del GAB, pero el sistema está dominado por el flujo en el GAB, que proporciona aproximadamente el 90% de la descarga. 利用南澳大利亚Freeling泉群部分泉水取样和电阻率成像(ERI)数据, 评估了地下水到泉水的来源和途径, 找到了大自流盆地(GAB)含水层系统(Algebuckina砂岩, Cadna-owie地层和横向等价物)和邻近山区基岩(MB)含水层之间水混合的证据。本文对5口泉水和1口水井进行了化学分析, 并收集了Freeling泉点上三个方向的多电极电阻率数据。电阻率数据显示了与水井相连的三个独立的导电曲线特征。这些特征证明了泉水排泄点的混合作用, 类似于利用传统水力流网进行预测分析。泉水水样化学分析结果表明, Freeling泉群的水来自GAB含水层和MB含水层水的混合, 与地球物理证据相符。数据表明, 混合作用主要发生在沿MB体的一条裂隙和GAB含水层中的多孔介质流动中, 但以GAB水流为主, 它占了约90%的排泄量。 A amostragem de água em nascentes que faz parte do Grupo Freeling Spring, sul da Austrália, foi usada junto com os dados de imagem de resistividade elétrica (IRE) para avaliar as fontes e os caminhos das águas subterrâneas para as nascentes e para encontrar evidências de mistura entre a Grande Bacia Artesiana (GAB) (Arenito Algebuckina, Formação Cadna-owie e equivalentes laterais) e águas do aquífero adjacente do embasamento de blocos montanhosos (BM). Foram utilizadas cinco nascentes e um poço para avaliar a química da nascente; dados de resistividade de vários eletrodos foram coletados ao longo de três orientações no site da Nascente Freeling. Os dados de resistividade indicam três características curvilíneas independentes...

Carbonate depositional systems related to groundwater upwelling are ubiquitous around the world and form ecologically and culturally important features of many landscapes. Spring carbonate deposits record past climatic and hydrological conditions. The reconstruction of past processes using spring carbonate proxies requires fundamental understanding of the factors that control their geometry. In this work, we show that the spatial extent of spring carbonate platforms is amenable to quantitative prediction by simulating the early growth stage of their formation for the iconic mound springs in the central Australian outback. We exploit their well-defined, circular geometry to demonstrate the existence of two size-limiting regimes: one controlled by the spring flow rate and the other by the concentration of lattice ions. Deviations between modelled and observed size metrics are attributable to diminishing spring flow rates since formation, enabling assessment of the relative vulnerability of springs to further hydrological change.

A major constraint on development in the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands is the lack of reliable water supplies. Sandstone strata found within palaeovalleys has long been recognised as potentially productive aquifers in outback South Australia. Although the APY Lands are known to contain such geologic features, their development as a viable water supply has been hindered by an acute lack of knowledge. An extensive airborne electromagnetic (AEM) survey was acquired as part of the Goyder Institute for Water Research’s Facilitating Long-term Outback Water Solutions Stage 3 (G-FLOWS S3) project in order to improve the understanding of groundwater resource potential in this remote region of South Australia. The AEM data revealed an intricate drainage pattern below the modern-day land surface that represents palaeovalleys. This facilitated the spatial refinement of these palaeodrainage features and provided a better understanding of their overall thickness. A targeted drilling campaign followed the AEM survey. Whereas the AEM data covers a large area of the APY Lands, drilling focused on two areas near the community of Kaltjiti (Fregon) in the eastern part of the APY Lands. Two hydrogeological test sites helped to understand and monitor the groundwater system associated with the Lindsay East Palaeovalley. Furthermore, drilling determined the true depth of the palaeovalley and provided a stratigraphic record. This enabled the validation of the AEM hydrogeophysical model, which included the identification of groundwater bearing zones within the palaeovalley. In total, 11 groundwater wells were constructed and continuous drill core was collected at the two sites. Drilling near the centre of the Lindsay East Palaeovalley suggests there are at least three groundwater-bearing zones. The basal coarse-grained sandstone unit of the younger palaeovalley fill shows promise as a productive aquifer, with development yields varying between 5 and 20 L/sec and salinities of <1000 mg/L TDS.