AN APPROACH TO IDENTIFY KARSTIFICATION BASEMENT: ANALYSIS OF SPRING SEDIMENTS MINERALOGY

In karstic aquifer systems, the groundwater velocity is relatively high and recharge usually occurs instantaneously and from point sources. Due to these properties, the allochtonous sediment carrying capacities of the karstic aquifers are high. The discharge through karstic springs are mostly characterized by turbulent flow. Therefore, there are many studies pointing out the fact that an increase in spring discharge coefficient in turn increases the degree of karstification.

The mineralogical investigations carried out in the sediments discharged by a karstic spring can give information about the recharge, storage and circulation features of an aquifer. One of the most important features that can be identified by these investigations is the karstification basement of the aquifer. The accumulation of the rock and sediment particles belonging to the lithological units located along the basement of the karstic aquifer indicates that the groundwater reaches the impermeable basement unit. In aquifers for which the karstification reaches the basement there is a tendency for the karstification processes to proceed in lateral direction. As a result, the existing fractures-cracks and the channels within the aquifer are anticipated to expand together with an increase in the karstification degree of the aquifer.

Within this context, the Susuz springs located in the Central Taurus Karst Belt were investigated. The karstic aquifer in the study area was developed within the Jurassic Polat formation limestones, which are underlain by the Triassic Seydişehir schists. There is a tectonic contact between these two formations. Polat formation is recharged from many point sources and it is discharged by Pınarbasi, Yagini, Boget, Alagoz, Icerikisla and Fasi bogazi springs. Petrographic evaluations and XRD analyses were carried out on the sediments collected from the spring discharge points. And as a result, the particles belonging to the schists and calc-schists of the Seydişehir formation together with the ones belonging to the formations located in the recharge zone of the aquifer were obtained. In conclusion, mineralogical data obtained in this study pointed out that the karstification reached the basement in the area.