0728 GMT January 20, 2022
Due to its diverse climatic conditions, Iran is a country of four seasons. The unique climatic features of the country, along with its special geographical location, have created very beautiful natural sceneries.
Various regions of the country, with different altitudes and diverse climatological conditions, have numerous landscapes, including mountains, waterfalls, forests and deserts, each of which is amazing in its own way. The pristine nature of Iran, sometimes mixed with the culture of its Indigenous people, brings a unique beauty to local and foreign tourists.
The book entitled, 'The Economic Geology of Iran,' published in 2013, was written by Mansour Ghorbani, from Department of Geoscience at Shahid Beheshti University in Tehran. It aims at providing an encyclopedic introduction to Iran’s natural resources.
The first chapter of the book covers the general characteristics of Iran’s nature, climate and its biodiversity. It is written in such a fashion which gives the reader an idea about Iran’s natural features and attractions even if one has never visited the country.
Following is an edited version of the chapter, accompanied by photos which appear in the book.
*Leila Imani is a staff writer at Iran Daily.
Location, boundaries and surface area
Iran is positioned in southwestern Asia, forming a bridge connecting the three continents of Asia, Europe, and Africa. It is bordered by the Republic of Azerbaijan, Armenia, Turkmenistan, and the Caspian Sea on the north, Afghanistan and Pakistan on the east, the Sea of Oman and the Persian Gulf on the south, and Turkey and Iraq on the west. The country is part of the Iranian Plateau that constitutes a vast and high terrain.
The Iranian Plateau is a triangular-shaped piece of land between the Persian Gulf and the Sea of Oman on the south and the Caspian Sea on the north and plays the role of a bridge between Central Asia and other plateaus in western Asia and Europe.
Half of Iran’s land surface is mountainous, one quarter covered by fertile and productive plains and the other one quarter covered with salty arid deserts.
Iran features a very diverse climatic and geographic characteristic. The highest temperature in the Persian Gulf area can reach up to 53°C in the summer, and the lowest temperature in the northwestern part of Iran can fall to −40°C in the winter. The average precipitation in the lush forests in the southwest of the Caspian Sea is about 2,400mm per year, whereas the Lut Desert may experience no rainfall for successive years.
The elevation at the Caspian Sea coast is 25m below sea level, whereas there are over 100 peaks, with heights of more than 4,000m, among which Mount Damavand is the highest, standing at 5,610m.
The biodiversity of Iran is as contrasting as its geography and climate. While the northern flanks of the Alborz Mountains are covered with deciduous forests, no trees can be seen in the millions of hectares of deserts. Mangrove forests cover the coasts of the Persian Gulf and the Sea of Oman.
Physiographically, Iran can be divided into four regions, namely, Caspian, Zagros, central plateau, and southern coastal plains. This division corresponds to the climatic conditions, vegetation, faunal distribution, and, to a great extent, geological and morphological characteristics.
Based on physiographical characteristics and the geographical and climatological literatures and maps, Iran can be divided into several climatic areas.
Naturalists divide the Northern Hemisphere into four major provinces, from a botanical point of view. Iran stands as a link between all these botanical provinces. Numerous factors from each of these provinces have affected the floral community of Iran. The four botanical provinces are:
Although only five percent of Iran’s plants are of European-Siberian origin, this small portion includes 80 tree species and more than 50 shrub species. Most trees in the Caspian region have managed to survive as they were situated at a far distance from the glaciers, but some trees that once existed there (Europe-Siberia) have not survived. Due to the lack of sufficient knowledge and research on the precise distribution pattern of these species, as well as the absence of data on fossil flora and fauna of Iran, there are many unanswered questions.
Much of the vegetation cover of the country consists of forests, prairies, and fruit groves and orchards. Not very far back, Iran had 30,000,000 hectares of forests, which accounted for 1/5 of its surface area; however, the number has been shrinking due to uncontrolled timbering. In general, 13.86 million hectares of land are presently covered with forests, and 90 million hectares with prairies.
Winter: During the winter, a high-pressure system forms over the Iranian Plateau whose effects are not as significant as those of the Central Asian wind systems. This weather system is of low-pressure type over the Black Sea, the Persian Gulf, the Sea of Oman, and the Indian Ocean.
In general, it can be said that the direction of winds during winter is from land toward sea; therefore, a large front of cold weather comes from Central Asia and moves toward the west, crossing over Turkmenistan and Kyrgyzstan. A branch off of this weather system shifts toward the Caspian Sea, but the mountains on the south and southwest block its flow. Only part of the moisture carried by this branch gets through into Iran via the Manjil Valley.
Spring: Spring is in fact a transitional period between the winter weather systems and summer weather systems. The length of spring is not the same in all locations; it is longer in the northwestern parts of the Iranian Plateau and Afghanistan, as compared to the central and southern parts. During spring, the high-pressure systems usually detour toward the west but do not totally disappear.
Summer: Low-pressure weather system dominates over southern Asia in the summer. To the north of this low-pressure system, there is a high-pressure system originating from the Azure islands. One of the effects of this high-pressure system is that a significant volume of oceanic weather starts moving toward central Europe, the Mediterranean, and the Alpine Mountains.
Autumn: Autumn is also a transitional period between the summer weather systems and the winter weather systems, meaning the weather systems of summer transform gradually toward wintery systems.
Iran has a wide range of bird species, and based on the statistical data, about 500 species have so far been identified, of which more than 350 species are reproducing in Iran.
This diversity is due to the geographic location of Iran as it is situated between several biogeographic areas, with specific bird species. Out of these 350 species, 250 belong to other geographic areas, where they evolved and then migrated to Iran and found habitats similar to their original ones to survive and reproduce.
Due to the vast expanse of Iran and its location between Saudi Arabia, the Caucasus, Turkmenistan, and India, and, more importantly, because of the unique nature of the Iranian Plateau, a wide variety of fauna is seen in Iran.
Mammals around the world are categorized into 20 orders, or 4,000 species. The mammals in Iran belong to 160 species, related to 10 orders, which is high, considering the area of Iran. The continent of Europe, with an area four times larger than Iran, has fewer mammal species.
Except the narrow plains along the Caspian Sea and the Persian Gulf and Khuzestan region, Iran is considered a highland, with an average elevation of 1,000m. The lowest point in Iran is located in the salt plains, northeast of Shahdad Desert on the margin of Lut Desert, with an elevation of 350m, and the highest point is Mount Damavand with a height of 5,610m, in the Alborz Mountains. In fact, Iran is a land which consists of a central plateau with mountainous margin, and this mountainous margin includes four mountainous areas: Alborz Mountains, Zagros Mountains, the central mountains, and the eastern mountains.
The Caspian Sea is located on the north, and the Persian Gulf and the Sea of Oman are south of Iran.
The Caspian Sea, with an area of about 436,000 sq.km, is the largest lake on Earth, with an elevation of 25-29m below the open sea level. The depth of the Caspian Sea is 10-12m in its northern part, 770m in the middle, and up to 1,000m in the southern part.
The Persian Gulf is a marginal sea with a length of 900km and width of 240km, whose depth varies from 35m to 100m. It is located on the south of Iran and is connected to the Sea of Oman and the Indian Ocean via a narrow strait, with a width of 60km, called the Strait of Hormuz. This gulf was formed 35 million years ago, and was much larger than it is today.
The Sea of Oman is part of the Indian Ocean and the only open seaway of Iran. The Persian Gulf is connected to the open seas via the Strait of Hormuz and the Sea of Oman. This sea is bordered by Iran in the north, Pakistan and India in the east, the Arabian Peninsula in the west, and the Indian Ocean in the south. The length of the Sea of Oman, from the Strait of Hormuz to Deccan, is about 600km, and it covers an area of 900,000 sq.km. It is relatively deep, and its depth near Chabahar port, in the southern province of Hormuzgan, is 3,398m. The length of the coastline of the Sea of Oman in Iran is 784km.
Most lakes in Iran are remnants of what was once a large sea, parts of which turned into swamps, and parts still exist. The most important existing lakes are Urmia, Qom Namak, Bakhtegan, Gavkhouni, Jazmourian, Zarivar, Maharlou, Parishan, Tar, and Hamoun.
The network of running water in Iran can be divided into four areas with respect to natural water flow, course condition, slope of water resources, estuaries, and basins:
● North intake basin: The water flow direction within this basin is usually toward the north, pouring into the Caspian basin.
● Western and southern intake basin: The water flow direction within this basin is toward the west and south, and ultimately ends in the Persian Gulf and the Sea of Oman.
● Lateral intake basin: The water flow direction is toward depressions and confined basins adjacent to Iran on the east or north side.
● Central intake basin: This includes confined basins within the central Iranian Plateau. Most of the water supply of Iran belongs to this area, but due to its climatic conditions, the area is considered dry, with low rainfall. The course of the water flow within this area is controlled by the mountain ranges surrounding the plateau. Alborz and Zagros mountains are the water distributor inside and outside the Iranian Plateau.
Due to the mountainous characteristics in parts of Iran, many present-day large and small rivers have been the source of life in various parts of the deserts and mountains in Iran for a very long time.
In general, the rivers in Iran are divided into two categories:
• Caspian Sea
• Persian Gulf
Most rivers that flow to the Caspian Sea originate in the northern slopes of the Alborz Mountains. Because of the short distance from the Alborz Mountains to the Caspian Sea, these rivers do not stretch very long.
Aras, Sefidrud, Se Hezar, Chalus and Haraz are among the most important rivers in this category, while Gamasiab, Karun, Jarrahi, Hendijan and Dalaki are the most important rivers that flow into the Persian Gulf.
The central Iran basin has deserts filled with quaternary rocks and sediments. Most of these deserts are seen in central and eastern Iran. In the central parts of these internal basins, there are large barren lands with low amounts of water and a high degree of evaporation, mostly in the form of salt flats, which are called “kavir.”
The total area of the deserts of Iran is 34 million hectares, which is almost 20 percent of the country’s surface area. The largest deserts of Iran are Lut and Namak (Salt), located in eastern and central Iran.