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Chahkuh Gorge

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 Gorge is located in the northwest part of the Qeshm Island, near West Chahu village.

Chahkuh Gorge is located in the northwest part of the Qeshm Island, near West Chahu village.

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.

Aerial photo of Chahkuh Gorge

Aerial photo of Chahkuh Gorge

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 another gorge perpendicular to the main gorge; also created by the same mechanism.

There is another gorge perpendicular to the main gorge; also created by the same mechanism.

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).

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.

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.

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.

One of the main reasons to name this place as Chahkuh (barrow-well) is because of the water wells in this area and the usage of them by local people in years.

One of the main reasons to name this place as Chahkuh (barrow-well) is because of the water wells in this area and the usage of them by local people in years.

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

Namakdan Salt Cave

Namakdan cave is among the most important geosites in the Qeshm Island Geopark (Hormozgan province, Iran). The salt dome (diapir) of Namakdan is a unique structure in the Island including several outstanding structural, mineralogical, erosional and sedimentary sceneries. In this Geosite the world record Namakdan Cave exists, the world longest salt cave, 6500 meters.

The Namakdan Salt Complex (Combrian) actually includes several smaller geosites. There are Salt flats, Playa, Salt springs, Amazing salt outcrops, Sink holes and many other structure and forms. This geosite has been registered in the National List of Natural Heritages (2010).

The main entrances of cave are N1, N2 and N3. N1 is open for general visits; visit to N2 needs arrangements with geopark management and should be done by geopark guide assistance. N3 is very delicate and also dangerous; it is possible to visit just for speleology professionals, geology specialist’s holded particular, written permission from the Qeshm Island Geopark management.

There is a spectacular polygonal form on the southern wall of salt dome in front of the sea. This structure created by salt surface fractures and step erosion in the beddings surface at the same time.

Geology of Salt Dome and Salt Cave

Namakdan Salt dome has an outcrop of 7 kilometer in diameter. This feature has covered the western plunge of Salakh Anticline. Namakdan Salt Dome has been formed from Hormoz Series deposits (preCambrian-Cambrian).

Because of its plasticity nature, it was always inclined to rise up to escape the pressure by upper rocks. Field evidences and seismic logs shows that Hormoz Series had a very slow movement and uplifting; so caused to thinness of the sedimentary formations and making slop in the basement.

Namakdan Salt Cave is located inside Namakdan Salt Dome resulting Karst process and salt dissolution and forming underground channels and galleries. Inside the cave there are different types of sedimentary forms and speleothems. Erosion forms are more than sedimentary forms because of the water high capacity of saturation.

Keywords: diapir , Geopark , Hormoz Series , Hormozgan province , Iran Geology , Iran Geotourism , Namakdan Cave , Namakdan dome , Qeshm Island , world longest salt cave , zamingasht