Introduction of Karst Geomorphology of Carbonate Rocks in Ahangaran Region (Northeast of Birjand)

Karstification process makes specific geomorphological features and forms typically slots، channels and large dissolution cavities. In this research، Ahangaran region which is located in northeast of Birjand (Southern Khorasan Province) with low temperature and more than 200 mm of annual rainfall has been studied for the purpose of recognition of karstic features. The Lower Cretaceous limestone forms the main carbonate rock unit in this region. There are relatively numerous karstic limestone masses in Ahangaran heights which study of them can be significant in identifying of karstic forms، limestone aquifers and relation of karst and water system in this region. Ahangaran karstic system is classified in arid climate karst types which have some springs. Drinking water for villages of this region is prepared from permanent and seasonal springs. In addition to springs، karens، rain pits and dry valleys could be noted as other geomorphological forms in this area. Development of secondary porosity as a network of joint and fractures and performance of karstic processes within the carbonate rocks are the most effective factors in karstification of this region.