Hydrogeology of Ereğli-Zonguldak hardcoal basin

This study covers the gological and hydrogeological studies which were carried out in Ereğli-Zonguldak Hard Coal Basin. Zonguldak and Ereğli are important places to be owner of hard coal basins, placed in north-west part of Turkey.Origin of the basin are the units of Silurien and Carboniferous formations. According to transregression Mesozoic formations which were discordans for covering the Palaeozoic formations, occured in Cretaceous. There are two units were discordans to their upper part of these formations are Senozoic that occured origion Quaternary alluvium and Palaeocene.In general units forming aquifers of the study area are Barremian and Aptian Limestones. The other rock units which could be aquifers of the study area are; Sandstone, Claystone which having Westphalian coal vein with following by conglomerate and Upper Barremian-Lower Aptian Sanstone, conglomerate with following by claystone.Cretaceous-Barremian limestones, Cretaceous -Aptian limestones, Cretaceous Aptian sandstones and carboniferous sandstones are suitable to be aquifer in this region. Study area has been effected by Hersinian and Alpine Orogenyses so that folds and faults developed. Limestones under the effect of tectonism became suitable for karsting and so many cavity systems occured in the working area.In the past theerteen pomping tests had been done to determine the caracteristic properties of the aquifers in the study area. Obtained datas from these tests indicate that the Barramien and Apsien formations are the karstic aquifers and Westphalien, Lower Apsien- Upper Barremien formations are the pressure aquifers from their structure properties of originating the following Claystones.Investigating the hydrogeochemical analyses of study area, it could be seen that the most of the waters are the similar origin and can be accepted in the strength carbonate group. According to previous studies of isotope analysis indicated that the samples of water are almost actual and have a meteroic origin.