Zagros Mountains
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The Zagros Mountains are the most extensive range in Western Asia in terms of the area covered. The tallest peaks are Mt. Dena and Mt. Zard-e Kuh Dena peak is shown which rises to 5098 m. |
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.
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.
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.
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The Zagros Mountains from space, September 1992 |
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.
