Investigation of effects component and types on Masjed-Soleyman Agha-Jari sandstone layers formation accompanied by hardness stone on potholes development

Potholes are one of the spectacular landforms of rocks, especially sandstones. In this paper, 48 samples of Agha-Jari Sandstones were prepared and thin sections were obtained from them to investigate the sandstone minerals and porosity by Polarizing microscope and also by Bernard calcium meter. For estimating of rock hardness we use Schmidt Hammer Model N and ISRM (1978) standard. Maps were prepared with 1:25000 topographic map, Arc/GIS software and Jmicrovision software was used to obtain the amount and percentage of thin section minerals. The results showed that Potholes are a function of physical conditions of rocks and mineralogy compounds of rocks with the erosion role of water flow in calcium carbonate of stone. Based on the data and results, it was found that the characteristics of Agha-Jari sandstone compounds play an important role in the generation of Potholes in this formation. It was determined that the abundant presence of Feldspar minerals and high percentage of porosity in the oldest layer (A) of Agha-Jari Formation plays a great role in the looseness and creation of Potholes in that layer. Other layers with Potholes such as (B, D, C, and F Layers) show a significant relationship between increasing quartz percentage and decreasing the percentage of feldspar and calcium carbonate. The results also showed that the mean calcium carbonate of Agha-Jari sandstone is about 50% which is one of the reasons for the existence of Potholes in layers despite the hardness of Schmidt Hammer is high.