Karst hydrogeology of Kusluk-Dilmetas karst springs, Van-Eastern Turkey

Permian marbles and recrystallised limestone nappes outcrop in the Artos Mountain range and comprise an aquifer with a small storage reservoir. Carbonate units are underlain by the impervious Yuksekova ophiolites. Between the marble and ophiolites, there is a transition zone by the northward thrusting, which varies between 500-1,000 m thickness. Fissures and fractures systems are well-developed in this transition zone because of the effects of tectonic movement, and extensive karstification has resulted in a high infiltration although its storage capacity is low. Because of the impermeable ophiolites at the base, groundwater discharges as springs flowing from the plane of the thrust faults. Numerous karst springs (48 springs) issue from this fissured and fractured zone, which are characterised by small discharge rates, a long residence time, and well-regulated spring flows. In addition, a selective enlargement is observed from west to east, which is greatly effected by strike-slip faults. All these springs are mostly fed by snowmelt during 6 months of the year