Abstract

The Sultan anticline (SA) is one of the most important sources of karstic water in the north of Poldokhtar city, southwest Iran. The Sarvak Formation (SF) limestone is inner main part of the SA. Age of the SF is upper Cretaceous. In this area 6 karstic wells are drilled with average depth of 130 meters (m). The wells are pumped more than 230 L/S of water. The location of the wells is in the Gol Gol valley that is a faulting valley. In this research, the effect of geological structures on the formation of water resources including wells and springs has been investigated. The results showed that geological structures, such as the Kalak Bisheh revers fault and tension joints, have an Impressive impact on the development of karst landforms. In the study area of the Kalak Bisheh fault has been removed, the outer cover of the SF includes Gurpi and Ilam Formations. The studies show that where the SF is uncovered on the joint’s location, especially tensile joints are formed caves and parallel galleries with the fold axis. The results show that the permanent and seasonal springs are respectively fault and contact type and are located in slope less than 5% and more than 12%. Also, in the study area, with increasing distance from the fault, the karst water resources are seen only in the form of permanent springs with a discharge of about 12 L/S in the Amiran and Gurpi Formations. At a distance of less than 1000 m from the fault, due to the removed of the SF cover are high the intensity of karstification and the development of water resources. It can be said that in the same areas, the most suitable place for the construction of new wells water is at the junction of perpendicular joints with the anticline of axis.

Keywords: Sultan Anticline; Poldokhtar city; Geological structures;Water resource; Iran