Determining the salinity sources of the Barme Jamal karstic spring, Meydavod, Iran
The Barme Jamal is an important karstic spring with mean discharge of 1.3 m3/s, located in the Meydavod county southwestern of Iran. Its outlet appeared in the Asmari limestone formation and drains the karstic limbs of Kuhe-Safid anticline. Naturally, the spring water salinity is more than expected for a karstic spring with EC about 2100 ms/cm. The spring water contains high concentration of SO4 and Cl with Ca–SO4 water type. Therefore, hydrogeochemical studies have conducted to determine the factors controlling the spring water salinity using hydrochemical techniques such as time series of chemical parameters, relative ion concentrations, Br/Cl ratios, TOC and mixing diagrams. The potential salinity sources such as mixing of karst freshwater with evaporites formation water and oil-field brine were investigated to determine the role of each source in the spring water salinity. The results reveal that the mixing of saline waters from evaporite formations is the main source of groundwater salinity. The hydrochemical time series illustrate that EC and Na–Cl are increasing in the spring water with almost constant rate throughout the studying period suggested the evaporites karst development in the spring catchment area and extension of dissolution conduits in the contact of limestone and evaporites formations.