The
Zagros Mountains (
Persian ???? ?????? ?????), (
Arabic ???? ???????), (
Sorani Kurdish Zagros - ??????), make up
Iran's and
Iraq's largest
mountain range. They have a total length of 1&_160;500&_160;km from western Iran, on the border with
Iraq to the southern parts of the
Persian Gulf. The mountain range ends at the
Straits of Hormuz. The highest points in the Zagros Mountains are
Zard Kuh (4&_160;548&_160;m) and Mt.
Dena (4&_160;359&_160;m). The
Hazaran massif in the
Kerman province forms an eastern outlier of the range, the
Jebal Barez reaching into
Sistan.
The Zagros Mountains were formed by collision of two tectonic plates — the Eurasian and Arabian Plates. Recent GPS measurements in Iran[2] have shown that this collision is still active and the resulting deformation is distributed non-uniformly in the country, mainly taken up in the major mountain belts like Alborz and Zagros. A relatively dense GPS network which covered the Zagros in the Iranian part [3]also proves a high rate of deformation within the Zagros. The GPS results show that the currnet rate of shortening in SE Zagros is ~10 mm/yr and ~5mm/yr in the NW Zagros. The NS strike-slip Kazerun fault divides the Zagros into two distinct zones of deformation. The GPS results also show different shortening directions along the belt, i.e. normal shortening in the South-East and oblique shortening in the NW Zagros. The sedimentary cover in the SE Zagros is deforming above a layer of rock salt (acting as a ductile decollement with a low basal friction) whereas in the NW Zagros the salt layer is missing or is very thin. This different basal friction partly made different topographies in either sides of Kazerun fault. Higher topography and narrower zone of deformation in the NW Zagros is observed whereas in the SE, deoformation was spreaded more and wider zone of deformation with lower topography was formed[4]. 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 oil production.
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.These mountains are nery hard to locate on a tiny map.
