Hydrogeology of carbonate rocks

Abstract

Carbonate rocks are sedimentary type of rocks containing more than 50% carbonate minerals which are mainly calcite, CaCO₃, and dolomite, CaMg(CO₃)₂. The carbonate minerals could be a result of chemical precipitation, organic processes or may occur as detrital material. Some of the dolomites may be a result of diagenesis known as dolomitization which involves replacement of calcite by dolomite to a varying extent. The term limestone is used for those rocks which contain more than 90% carbonates. If the rock contains more than 50% but less than 90% carbonates, it is termed as arenaceous limestone or an argillaceous limestone, depending upon the relative amounts of quartz and clay minerals. Chalk is a type of limestone which is soft and white in colour and is rich in shell fragments.