On the hydrology of the bauxite oases, Cape York Peninsula, Australia

•Little is known about the hydrology of bauxite deposits.•A new super group of large permanent springs is revealed in northern Australia.•Rich ecosystems supported by these springs are classified in a new sub-ecosystem.•Chemistry reveals these new springs are not part of the Great Artesian Basin.•Rather the springs are connected to one of the world’s largest bauxite formation. One of the world’s largest bauxite deposits is located in the Cape York Peninsula, North-East Australia. Little is known about the hydrology of these remote bauxite deposits. Here, we present results from a multidisciplinary study that used remote sensing, hydrochemistry, and hydrodynamics to analyse the occurrence of several large oases in connection with the bauxite plateaus. Across this vast region, otherwise dominated by savannah, these oases are sustained by permanent springs and support rich and diverse new sub-ecosystems (spring forests) of high cultural values to the local indigenous population. The spring water chemistry reveals a well-mixed system with minor inter-spring variation; TDS values of spring waters are low (27–72mgL−1), major ion compositions are homogenous (Na–Si–DIC–Cl) and δ18O and δ2H values are reflective of rainwater origin with little evaporation prior to recharge. Dating of spring waters with anthropogenic trace gases (CFC-12 and SF6) indicates mean groundwater residence times ranging from