Chahkuh Gorge is located in the northwest part of the Qeshm Island, near West Chahu village. This Geosite is a good example of running water erosion and formation of a canyon form valley. The erosion was the secondary parameter to create this valley; it was happened along a deep joint and crack resulting the Salakh Anticline movement. So the primary parameter was the structural forces.
Chahkuh geological formation are inside the Salakh Anticline, near the salt dome appearance location. Anticline is a ridge-shaped fold of stratified rock in which the strata slope downward form the crest. Resulting the internal pressures and stretches many cracks, joints and faults appear on the anticline flanks those are the weakest points toward erosion. Chahkuh Gorge is a primary joint developed by erosion.
There is another gorge perpendicular to the main gorge; also created by the same mechanism. In general, anticlines and unstable locations so there always appear many faults and joints.
There is variety of shapes and form namely orbicular, dished, oval and linear on the walls or floor of the gorge all created by the powerful running water after raining. In some cases pieces of rock moves fast and circular inside the gorge and curves the surface to create wells and bowl shape holes (pot-hole).
Geological formations in Chahkuh is impermeable (Aghajari Fm.); it causes rain water to run over the surface. Local people invented a genius innovation using this feature; they dug some shallow wells in the surface to reserve rain water and use it. While Qeshm Island is an extremely dry area, water is worthy and important there; that’s why this innovation is very interesting and practical.
Chahkuh Gorge is created inside alternation of sandstone and marl formation of Aghajari – Mishan (Miocene-Pliocene). This formation comprises of cream color thin bedded limestone that gets thicker on the top part. Over the limestone part, soft sandstone bed appears. The sandstone consist of carbonate particles so it is not very resistance to the erosion. There are some parameters which affects the resistance of the sandstone and creating erosion forms: context and existence of vertical joints.
Keywords: Aghajari formation , Chahkuh , Geosite , Gorge , Hormozgan province , Iran Geology , Iran Geotourism , Island , Qeshm , zamingasht