Paradise for geologists

Welcome to incredible Iran: Paradise for geologists!

Give us your hands until to familiar with beauties of Iran. Geological history of Iran is full of events, created widespread volcanic, magmatic and metamorphic outcrops. Thick stratigraphic sequences are naked across the country.

Our country hosts so many major faults, long anticlines and perched synclines, the beauty phenomena for structural geologists. Iran also is the country of Quaternary deposits and landforms extend from mountains top (glaciers) to the hill slope (alluvium) and from there to the lowlands in central Iran where the fascinated deserts, salt lakes, sand dunes and Yardangs have created a very attractive landscape for geologist and geomorphologists.

West of Iran is domain of karstic features, such as beautiful caves and large sinkholes which are formed during the last glacial stage.

Landslides are frequent in everywhere, including the Seimareh landslide with kilometers in length and width, well known as the largest landslide in the world.

The Zagros Mountain is located in the south and southwest of Iran. The famous structural – sedimentary zone contains the largest oil and gas reservoirs.

Our international guests can see the continuous stratigraphic sequence with several kilometers thick from Jurassic up to Pliocene, bare and easily to investigations.

The south of Iran also is the best place for visit unique salt domes, mud volcanoes and recent reefal limestone.

Iran also has an exceptional geographic and climatic conditions. The difference temperature between north and south sometimes reaches to 30 centigrade.

In the North, the shore line of the Khazar Sea, as the largest lake in the world, and its surrounding area with mountainous forest, are the attractive place for millions of tourists in all seasons. In this region, the natural beauties are in your path.

Toward central and southern parts of Iran can enjoy the magnificent and beautiful deserts, Kavirs as well as salt lake and playas have extended far away.

Damavand, Sabalan and Sahand as the most famous volcanoes of Iran and their young volcano-clastic rocks welcome to all volcanologists throughout the world.

There are so many Geo-parks and Geo-sites that increase your familiar with other natural beauties of Iran.

All attractions with low cost traveling, unbeatable security and hospitable people will excite you for travelling to Iran again and again.

“ZaminGasht” is a window to meet you the natural beauty and geological phenomena of Iran. We have numbers of Iranian experts in all branches of geoscience who can identifying natural beauty of Iran to all international geoscientists and geo-tourists.

Pirzal Perched syncline

In the Kohgiluyeh and Boyer Ahmad province in the southwest of Iran, along the road of Dehdasht to Sarfariab city, when pass through the pirzal gorge, we enter to the plain between the two mountains “Siah” and “Mondon”. The two mountains, Siah and Mondon, are anticlines that extend along the northwest to the south-east. In the plain between the two anticlines, there is a beautiful perched syncline.

Syncline is a geologic feature like a “V” fold in layered sedimentary ground, which often occurs when the layers tend to go horizontally, but twisted by the tectonic forces. In analogy, an “anticline” is the convex opposite form, where the sedimentary layers form a dome, and a “monocline” is flat.

A “perched syncline”, or “perched synclinal”, differenciates itself by the fact it stands elevated from the surrounding terrain. Contrary to the monoclines, they form very characteristic mountains, looking like fortresses surrounded by walls.

In fact, a perched syncline is formed when the central layers of syncline (younger) have more resistance than the outer layers (older) against erosion. In this case, the outer stones are eroded and the strong rocks remains in the center. These strong rocks remain in the form of a ship stands elevated from the surrounding terrain and form a perched syncline.

In center of Pirzal perched syncline, thick to medium bedded limestone (Asmari formation – Oligomiocene in age) and on the sides, alternation of Marl and thin bedded limestone (Pabdeh formation – Eocene to Oligocene) have been outcropped. Over the time, marls have been eroded, and strong limestones remain in the center.

This beautiful photo was taken by M.S.Zangeneh looking northward.

Keywords: Iran , Kohgiluyeh , Zagros , Anticline , Syncline , Perched syncline , dehdasht , sarfaryab , geology , geotourism , asmari formation , pabdeh formation , mondon anticline , kuh e siah anticline , pirzal gorge , zamingasht

Abarkuh Sinkholes

The Sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes—for example, the chemical dissolution of carbonate rocks or suffusion processes. Sinkholes vary in size from 1 to 600 m both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Sinkholes may form gradually or suddenly, and are found worldwide.(wikipedia)

Abarkuh County in south-west of Yazd province in center of IRAN have faced with some sinkhole occurrences in recent years which have caused significant damages to agriculture lands and other infrastructures of villages in this area.

From 2000 to 2005 more than 30 sinkholes had happened near Faizabad village. According the geological map of this area, sinkholes have formed on quaternary layers with maximum 13.5 meters and minimum 0.5 meters deep.

Photo by: Siamak Mohammadi Sivandi


Keywords: Abarkuh , Geology , Geotourism , Iran , Quaternary , Sediment , sinkhole , underground water , zamingasht

Mila Formation in Central Alborz

The Mila Formation is one of the Cambrian formations in Alborz.  The Mila Formation has 5 measurable members in type section (Mila Kuh, Damghan City). This formation overlies conformably the Early Cambrian Lalun Formation and underlies disconformably the Early Devonian red conglomerates. But on the Chalus road in Central Alborz, four members of this formation are visible and measurable.

The first member is a white base quartzite (BQ), which in the past was a member of the lower formation (Lalun), but according to detailed studies, the boundary of this unit with underlying sandstone layers is considered to be discontinuous.

The Second member consist of Dolomite with interbedded of yellow Shale and Marl. Third member is well bedded Limestone with a few shale. Forth member is course grained glauconitic limestone. Fifth member consist of Siltstone, Sandstone, Glauconitic limestone and Marl.

In the Image, Mila formation outcrops in Chaloos road, near Hasanakdar Village. Because of the tectonic forces, the rocky layers are cut, broken, and displaced by faults.

The lower boundary of this formation with the Lalun Formation is para unconformity and indicated with the white quartzite layers. The upper boundary of this formation in this area is determined by the Hassanakdar fault and the outcrop of lava in the Geirud Formation. All the thickness of the Mila Formation (without quartzite) in the Karaj valley is 395 meters (Lorenz, 1964). In this region without the quartzite member, only three members of the Mila Formation have been identified.

In the photo, the formations of Lalun (La), Mila (Mi), Ruteh (Ru), Jeyrud (Je), Elika (El) and quartzite member of the Mila Formation (BQ) are seen.

Keywords: Iran , Central Alborz , Geology , Geotourism , formation , Mila , ruteh , jeyrud , elika , chaloos road , limestone , sandstone , siltstone , dolomite , shale , marl , zamingasht

Alborz Mountain Range

Alborz (Persian: البرز‎‎), also spelled as Alburz, Elburz or Elborz, is a mountain range in northern Iran that stretches from the border of Azerbaijan along the western and entire southern coast of the Caspian Sea and finally runs northeast and merges into the Aladagh Mountains in the northern parts of Khorasan. This mountain range is divided into Western, Central, and Eastern Alborz Mountains. The Western Alborz Range (usually called the Talish Mountains) runs south-southeastward almost along the western coast of the Caspian Sea. The Central Alborz (the Alborz Mountains in the strictest sense) runs from west to east along the entire southern coast of the Caspian Sea, while the Eastern Alborz runs in a northeasterly direction towards the northern parts of the Khorasan region southeast of the Caspian Sea. Mount Damavand, the highest mountain in Iran, is located in the Central Alborz Mountains.

The Alborz mountain range forms a barrier between the south Caspian and the Iranian plateau. It is only 60–۱۳۰ km wide and consists of sedimentary series dating from Upper Devonian to Oligocene, prevalently Jurassic limestone over a granite core. Continental conditions regarding sedimentation are reflected by thick Devonian sandstones and by Jurassic shales containing coal seams. Marine conditions are reflected by Carboniferous and Permian strata that are composed mainly of limestones. In the Eastern Alborz Range, the far eastern section is formed by Mesozoic (chiefly Triassic and Jurassic) rocks, while the western part of the Eastern Alborz Range is made primarily of Paleozoic rocks. Precambrian rocks can be found chiefly south of the city of Gorgan situated in the southeast of the Caspian Sea and in much smaller portions in the central and western parts of the Central Alborz Range. The central part of the Central Alborz Range is formed mainly of the Triassic and Jurassic rocks, while the northwestern section of the range is made mainly of the Jurassic rocks. Very thick beds of the Tertiary (mostly of the Eocene) green volcanic tuffs and lavas are found mainly in the southwestern and south-central parts of the range. The far northwestern part of the Alborz that constitutes what is called the Western Alborz Range or the Talish Mountains is made mainly of the Upper Cretaceous volcano-sedimentary deposits with a strip of Paleozoic rocks and a band of Triassic and Jurassic rocks in the southern parts, both in a northwest-southeast direction. As the Tethys Sea was closed and the Arabian Plate collided with the Iranian Plate and was pushed against it, and with the clockwise movement of the Eurasian Plate towards the Iranian Plate and their final collision, the Iranian Plate was pressed from both sides. The collisions finally caused the folding of the Upper Paleozoic, Mesozoic, and Paleogene rocks, and the Cenozoic (chiefly the Eocene) volcanism to form the Alborz Mountains mainly in the Miocene. The Alpine orogeny began, therefore, with Eocene volcanism in southwestern and south-central parts of the Alborz and continued with the uplift and folding of the older sedimentary rocks in the northwestern, central and eastern parts of the range during the orogenic phases of importance that date from the Miocene and the Pliocene epochs.

In the photo above, the mountain overlooking the plain of Tehran (capital of Iran) can be seen. The mountains have formed the southern boundary of Alborz Mountain. The highest peak in this section, is Tochal (3962 meters). In the far right of the photo, Mount Damavand (5671 m), the highest peak in Iran is seen. This peak is the highest volcano in Asia.

In the southern part of Alborz in northern Tehran, pyroclastic rocks, shale and volcanic rocks are abundant. This stones are called green series or “Karaj formation”. More than 3,000 meters of sediments were deposited at the Eocene in this part of the Alborz, and the Karaj formation is created.

The Photo was taken by Amir Hossein Azizian, over “Milad Tower” in Tehran.

Keywords: Alborz Mountain , Elborz , Elburz , Eocene , Iran Geology , Iran Geotourism , Karaj formation , Milad tower , Mountain range , Orogeny , Pyroclastic ,Tehran , Tochal peak , Volcanism , zamingasht

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