Zagros mountains
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The Zagros Mountains (Persian: رشته كوه زاگرس), (Kurdish: Çîyayên Zagrosê), make up Iraq's and Iran largest mountain range. They have a total length of 1500 km from western Iran, specifically the Kurdistan region on the border with Iraq to the southern parts of the Persian Gulf. The range ends at the Straits of Hormuz. The highest point in the Zagros range is Mt. Dena at 5098 m/16998 feet.
Formed by collision of the Eurasian and Arabian tectonic plates, the range extends for hundreds of kilometers. Stresses induced in the Earth's crust by the collision caused extensive folding of the preexisting layered sedimentary rocks. Subsequent erosion removed softer rocks, such as mudstone (rock formed by consolidated mud) and siltstone (a slightly coarser-grained mudstone) while leaving harder rocks, such as limestone (calcium-rich rock consisting of the remains of marine organisms) and dolomite (rocks similar to limestone containing calcium and magnesium). This differential erosion formed the linear ridges of the Zagros Mountains. The depositional environment and tectonic history of the rocks were conducive to the formation and trapping of petroleum, and the Zagros region is an important part of Persian Gulf production.
Salt domes and salt glaciers are a common feature of the Zagros Mountains. Salt domes are an important target for oil exploration, as the impermeable salt frequently traps petroleum beneath other rock layers. Since the northern part of Zagros encompasses much of the historic Kurdish regions of Middle East, it has also been referred to as Kurdish Mountains or Kurdistan Mountains.
Etymology
The name Zagros is derived from the Zagarthians/Sagarthians--and Indo-European, Iranic immigrants from Europe who once inhabited the mountains, from the shores of Lake Van to the coasts of Makran. The Zangana and Chigini tribes of the Kurds are the remnants of these ancient Sagarthians. Other explanations deriving the name from Greek Zagreus, meaning stormy, or the name Za-G'R' means 'great mountain' in the Avestan language, are invalid.Type and age of rock
The mountains are divided into many parallel sub-ranges (up to 10, or 250 km wide), and have the same age and orogenesis as the Alps. Iran's main oilfields lie in the western central foothills of the Zagros mountain range. The highest point of the range is Zard Kuh (4548 metres). The southern ranges of the Fars Province have only somewhat lower summits of up to 4000 m. They contain some limestone rocks showing abundant fossils. Special surveyor expeditions sometimes come across fossil snails of 2 kilograms at altitudes of 3000 metres. It is now hard to imagine that these high summits were indeed part of the deep ocean some 50 million years ago. The second highest peak is named Dena.
The Kuhrud Mountains form one of the parallel ranges at a distance of approx. 300 km to the east. The area between these two impressive mountain chains is home to a dense human population that lives in the intermediate valleys which are quite high in altitude with a temperate climate. Their rivers, which eventually reach salt lakes, create fertile environments for agriculture and commerce.
Zagros in history
References
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