Armenia is the most mountainous of all the republics of Transcaucasia. The average altitude of its territory reaches 1800m above sea level. This is almost twice the average height of Asian land. Even the lowest parts of Armenia lie above 400m, in other words, there are no lowlands in the republic.
Occupying a small north-eastern part of the vast Armenian Highlands, Armenia repeats almost all the features of its nature, relief, climate, vegetation and wildlife, therefore the physical and geographical characteristics of the republic can begin with a brief description of the general features of the nature of this entire region.
The Armenian Highlands are, as it were, wedged between the Iranian and Asia minor mountain structures and rise above them by almost 500m. That is why it is called the “mountain island”. Its area is more than 300 thousand square meters. km with an average altitude of 1700m.
The highest point of the Armenian Highlands is Masis (Great Ararat) – a biblical giant, reaching 5165m.
The highlands are surrounded by high mountains on almost all sides: from the north – the Pontic mountains, from the northeast and east – the Lesser Caucasus ranges, from the south – the Armenian Taurus ranges. The natural features of the highland, closed by mountain ranges, are determined by its geographical latitude, the history of geological development, the diversity of relief and large fluctuations in absolute heights.
The Highlands are often called the land of extinct volcanoes, but the Nemrut volcano (west of Lake Van) is still active from a geological point of view “today”. Echoes of mountain-building processes and volcanism are also the high seismicity of the country and the release of numerous hot springs. The complex geological history explains the diversity and richness of mineral resources. Some of them: gold, silver, valuable building stones have been mined and processed by Armenian craftsmen since time immemorial. English archeologist Gordon Childe and other researchers proved that the ancestors of Armenians were among the first tribes in the world that began to mine ore, discovered iron and started the Iron Age. The Armenian Highlands were the “epicenter of the Iron Age”.
Armenia, as already noted, occupies one of the most mountainous parts of the Armenian Highlands. More than 90% of its territory is elevated above 1000m above sea level. The lowest places are the valleys of the Araks and Debed rivers at the southeastern and northeastern outskirts of the republic (about 400m), and the highest point is the top of Mount Aragats (4090m).
The arc of the Lesser Caucasus ridges, like a wall, limits the highlands and separates it from the lowlands of Transcaucasia. The arcuate system of ridges consists of two, and in the middle part of three or four rows of either parallel or converging mountain ranges. The central ridges of the Lesser Caucasus are composed of various sedimentary and volcanogenic Mesozoic rocks, and the outer ranges are composed of Tertiary marine sediments. All these mountain systems were initially crushed into folds, and later broken by transverse and longitudinal faults and therefore now form folded-block structures, slightly inclined to the northeast and abruptly ending towards the highlands.
On the border of Armenia with Georgia stretches the Somkheti or Virahayots ridge. To the west of the Lori plateau lies the higher, but smaller in area, Ashotsk plateau (1800-2000m). Between them rises the meridional volcanic ridge – Javakheti.
To the south of Ashotsk stretches one of the most extensive and fertile plains of Armenia – the Shirak Plateau (altitude 1400-1500m).
To the south of the Lori Plateau, the Bazum and Pambak ridges stretch almost in the latitudinal direction, between which the Pambak River basin is located. The ridges reach 3000m in height and are composed of limestone and fairly young volcanic rocks – porphyrites. In both ranges, the northern slopes are moist and wooded, while the southern slopes are covered with dry steppe vegetation.
In the west, the ridges converge, forming a low bridge – the Dzhajur Pass, through which the path from the Pambak basin to the Shirak plateau goes.
To the east, the ridges gradually diverge and branch: to the northeast of Bazum, the Gugarats ridge stretches – the watershed between the Debed and Aghstev rivers.
One of the wings of the Pambak ridge goes to the north of Sevan, where it connects with the Areguni ridge, bordering the northeastern coast of the lake, and the other – Tsaghkunyats – descends to the southeast to the wooded Marmarik valley, where the Tsaghkadzor ski center is located.
In the east of the republic, almost at an altitude of 2000m, there is the Sevan Basin with Lake Sevan.
To the west of the Sevan basin, at the foot of the Geghama Mountains, lies the Ararat Plain, one of the largest tectonic trenches in the highlands. In the north, the plain is limited by the base of Mount Aragats, in the south – by Ararat. It is divided into two parts by the Araks River. The south is located within Turkey.
To the south of Sevan and the Vardenis Mountains lies Syunik, uniting the historical mountain regions of Vayk and Zangezur.
On one side, the Vardenis ridge connects with the Geghama ridge through the Gndasar mountain junction. To the southwest stretches a small ridge with a typical volcanic cone – Vayotssar. Another ridge – East-Sevan stretches to the northeast. It is rich in gold reserves (Zod). To the south stretches the powerful Zangezur ridge, bordering the Nakhichevan Autonomous Republic. It ends in the wild gorge of the Araks between Meghri and Ordubad. This is one of the longest and highest ridges in Transcaucasia: its peak Kaputjugh (3906 m) is second only after Aragats. One of its spurs, the Vayk ridge, extends to the west and borders the Arpa River basin from the south.
Other spurs – Bargushat (between Goris and Kapan regions) and Megri (between Kapan and Megri) branch to the east-southeast and reach an altitude of 3000-3400m.
The Zangezur ridge and its spurs are composed of both young volcanic and intrusive and older sedimentary rocks and are rich in minerals, mainly non-ferrous metals (copper, molybdenum) and iron.
In the northeast, the Syunik volcanic highland adjoins the Zangezur ridge (Mount Mets Ishkhanasar – 3552 m).
The Armenian Highlands, together with the Lesser Caucasus, are a link in a huge belt of the highest mountains and highlands, crossing the southern edge of the great continent of Eurasia from the Iberian Peninsula to the Indonesian Islands. The mountains of the belt arose on the site of the ancient Tethys Ocean. We now find layers of bottom sediments of its seas in the structure of both the mountains and valleys of the modern continent that rose on the site of Tethys. At one time, mountains rose from the ocean floor as a result of mountain-building processes that gradually turned the former ocean into land.
Tectonic processes occurred here more than once. But the most powerful of them occurred “recently” – during the relatively young, so-called Alpine era of mountain building, which began over 60 million years ago.
The territory of Armenia is a “geological museum”, where you can find images of almost all the rocks that make up the crust of our planet, from the oldest to the youngest.
The most ancient era – the Archean, or Precambrian – was the time of the birth of the earth’s crust. On the territory of the republic, rocks of Precambrian age – metamorphic schists, quartzites, gneisses – protrude onto the surface along the right bank of the upper reaches of the Hrazdan River, in the central part of the Virahayots ridge, etc. In other areas of the republic, the Precambrian foundation is absent or goes deep under later layers ( under the Ararat plain to a depth of 600 m). Above are the layers of the Paleozoic – the era of the appearance of life on Earth.
Billions and billions of dying simple organisms over hundreds of millions of years formed thick layers of limestone during this era. Paleozoic limestones are found in the south of the republic, on the southeastern foothills of the Geghama Range, south of the Vedi River to the western extremities of the Vayk Range. Limestones consist of tiny shells and calcite, which was chemically precipitated from seawater. Some of the local limestones, under the enormous pressure of the overlying layers and the influence of high temperatures, turned into marble. In the area of Ararat station there are huge layers of travertines. Travertines are a product of the deposition of springs that once emerged from Paleozoic limestones. They are used to produce cement, calcium carbide.
In the next Mesozoic era, the seabed was subjected to compression, powerful folds formed. Lavas poured out, which, solidifying under water, formed volcanic rocks: porphyrites, tuff breccias, tuffs, etc. Part of the current territory of the country in the northeast and south, rising from the depths of the sea, became dry land, but then, by the end of the Mesozoic era, again found itself under water, where new thick layers of limestone accumulated.
The Bazum and Pambak ridges, as well as the Sevan ridge and the northeastern regions, are composed of limestone and other marine sediments of Mesozoic age.
In the newest, Cenozoic era, most of the territory of Armenia was again subjected to the most powerful mountain-building processes (the so-called Alpine orogeny). As a result, it finally became dry land.
In the low-lying parts of the territory, for example, in the Ararat Basin, shallow seas or lakes still remained for some time; they retreated and evaporated, leaving clay, gypsum, and salt in place of the bottom. Under the surface of the Yerevan basin, in thick layers (up to 120-130 m), there are layers of table salt, which is now being mined for food needs and as a raw material for the chemical industry.
Simultaneously with mountain building and mainly after the land hardened, new tectonic movements led to the formation not of folds, but of huge and deep faults. These movements transformed and “rejuvenated” a greatly eroded and almost leveled country.
Broken by cracks, it experienced powerful arched uplifts. During the uplifts, some blocks formed mountain ranges, and during the subsidence of other areas, areas of relative depression arose (for example, the Sevan basin). This is how the modern relief of the Lesser Caucasus Arc arose, part of which is included in the territory of Armenia. It is characteristic that on the crests of these ridges the remains of eroded surfaces are preserved in places. There are even several levels of such “leveling surfaces.”
Inside the Lesser Caucasus arc, as a result of large faults, especially in the last stage of the Cenozoic – the Quaternary period, a new cycle of volcanic activity began. The mountains erupted billions of tons of molten matter and ash. Compared to the cycles of previous eras, Quaternary volcanism was the most violent.
Many volcanoes were still breathing fire before the eyes of our ancestors. Lava, which spread from the centers of eruptions, filled the former basins, covered the plains and, cooling, formed a solid stone armor with a thickness of up to 170-180 and in places up to 400 m. The predominant rocks formed at this time are basalts, andesites, tuffs.
In some areas (for example, near the village of Arzni), scientists have recovered various tools from under layers of lava and ash, and traces of prehistoric man’s sites have been discovered. This is evidence of a very young age of the lavas.
On a wide strip (from the northwestern borders to the left bank of the Vorotan River), on ⅓ of the territory of the republic, the ancient relief is buried under young igneous rocks. Above these covers, large and small volcanic cones rise in groups or singly along fault lines, topped with deep craters. These are extinct volcanoes, former centers of eruptions. They are composed of alternating layers of volcanic rocks or entirely of slag.
After volcanic eruptions, glaciation begins on the highest mountain nodes of Armenia. The peaks and ridges of Aragats, Geghama, Vardenis, Zangezur, Javakheti ranges are covered with thick snow cover, and glaciers form in the valleys and basins. Traces of Quaternary glaciation in Armenia are karas, troughs, moraine deposits and ridges. In some places these deposits are covered by lavas. This is evidence of alternating phases of volcanic eruptions and glaciations.
The solidified lava fields are now mostly covered with fertile chernozem soils with steppe vegetation.
As the country rose, the rivers cut into the rocks, deepening their channels, “sawing through” even the hardest volcanic rocks. The gorges of the Vorotan and Debed rivers formed in this way reach a depth of 400-500 m. The valleys of Hrazdan, Akhuryan, Dzoraget, and Arpa are somewhat less incised.
The slopes of the wider valleys rise in several terraced steps. Their formation is associated with the so-called neotectonic movements, recent and modern intermittent uplifts.
By the way, the young age of the lava covers is also proven by the fact that many of them lie on river terraces right down to the lowest and, therefore, the youngest.
Volcanic rocks are an excellent building material. A special place among them is occupied by tuffs – pink, orange, black, yellow; tuff is used not only for construction projects in the republic, but is also exported beyond its borders. Its reserves are huge.
In some places, during volcanic processes, magma did not reach the surface and froze in the layers of the earth’s crust. These penetrations, or intrusions of magma brought with them from the depths solutions of metals, which, when cooled, formed ore deposits.
Armenia is rich in deposits of copper, molybdenum, polymetallic ores, and iron. Three metallogenic zones are distinguished. In the zone running from Alaverdi to Kapan, the bowels of the earth are rich in copper pyrite ores. There is also zinc, lead, barite with an admixture of gold and silver. The Alaverdi, Shamlut, Kapan copper pyrite and Akhtala polymetallic deposits are known.
Somewhat to the southwest, parallel to the first, there is a second zone – Pambak – Zagezur, which is rich in copper-molybdenum ores. The largest are the Kajaran, Agarak, Dastakert and Lichk copper-molybdenum deposits. The first three are already in operation and molybdenum concentrates are sent to the country’s metallurgical centers for the production of high-quality ferromolybdenum alloy and very strong alloy steel. In this zone, in the valley of the Marmarika River and in the Meghri region, there is also a raw material for aluminum – nepheline syenites.
Several iron ore deposits have been discovered in the republic. Their total reserves exceed 1 billion tons. To the north of Yerevan there are the Hrazdan and Kaputan deposits with a metal content in the ore of up to 40-65%; There are also apatites here that can be used to produce superphosphate. The largest iron ore deposit is Svarants (about 500 million tons) in Zangezur. Among ferrous metals, deposits of manganese are also promising.
The third, Sevan-Amasia metallogenic zone is known for high-quality magnesium-chromite ores, which were discovered on the northeastern coast of Sevan. There are also occurrences of platinum and deposits of indigenous gold on the East Sevan Ridge. In some places there are accumulations of antimony, mercury and arsenic (realgar).
The article was compiled based on observations and materials collected by the ArmLand club.
Author of photos: Artyom Martirosyan, Gohar Sargsyan and Hayk Barseghyan