Gegham mountains (or Gegham Ridge, ISO 9985: Geġam), hy, Գեղամա լեռնաշղթա (''Geghama lernasheghta'') are a range of mountains in

Armenia Armenia (), , group=pron officially the Republic of Armenia,, is a landlocked country in the Armenian Highlands of Western Asia.The UNbr>classification of world regions places Armenia in Western Asia; the CIA World Factbook , , and ' ...

. The range is a tableland-type watershed basin of Sevan Lake from east, inflows of rivers

Araks , az, Araz, fa, ارس, tr, Aras The Aras (also known as the Araks, Arax, Araxes, or Araz) is a river in the Caucasus. It rises in eastern Turkey and flows along the borders between Turkey and Armenia, between Turkey and the Nakhchivan excl ...

and

Hrazdan Hrazdan ( hy, Հրազդան), is a town and urban municipal community in Armenia serving as the administrative centre of Kotayk Province, located northeast of the capital Yerevan. As of the 2011 census, the population of the town is 41,875. I ...

from north and west, Azat and Vedi rivers from south-west and Arpachai river from south. The average elevation of the Gegham mountain range is near 2500m. The range is of volcanic origin including many

extinct volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

es. The range is 70 km length and 48 km width, and stretch between

Lake Sevan Lake Sevan ( hy, Սևանա լիճ, Sevana lich) is the largest body of water in both Armenia and the Caucasus region. It is one of the largest freshwater high-altitude (alpine) lakes in Eurasia. The lake is situated in Gegharkunik Province, ...

and the Ararat plain. The highest peak of the Gegham mountains is the Azhdahak, at 3597m. They are formed by a

volcanic field A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes ...

, containing

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

-to-

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

lava domes and cinder cones. The highland reaches a height of 1800–2000m up to 3000m in the dividing ridge.

Geological history

Volcanism in Armenia and in the Gegham mountains is related to mantle processes accompanying, but not necessarily related to the collision of the

Arabian plate The Arabian Plate is a minor tectonic plate in the Northern and Eastern Hemispheres. It is one of the three continental plates (along with the African and the Indian Plates) that have been moving northward in geological history and colliding ...

with the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

. Unlike in other parts of the

Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range ...

region, the Gegham mountains have generated primarily small scale volcanoes. The Kaputan Formation (including Mt. Atis and Gtsain Ridge) from the Late Miocene has been dated at 5.7–4.6 Ma by K-Ar and is the oldest sequence in the region.

Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

activity involved various

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

ic lavas (including Lchain Volcano) and subsequently, during the Quaternary, rhyolite and obsidian from the Kotayk centre (Gutansar and Atis 700 ka, then associated fissure volcanoes 550–480 ka). The volcanic activity peaked round 200 ka, when most of the Gegham centres formed from

trachyandesitic Trachyandesite is an extrusive igneous rock with a composition between trachyte and andesite. It has little or no free quartz, but is dominated by sodic plagioclase and alkali feldspar. It is formed from the cooling of lava enriched in alkal ...

lavas. Aknotsasar and Sevkatar were active less than 100ka ago. The highest point is the volcano Azhdahak, elevation - 3597.3m above sea level, in the western part of the range. There is a lake in the crater of the volcano Azhdahak that is formed from melting snow. The volcanoes Spitaksar (3560 m) and Geghasar (3446 m), the former erupted 120ka ago and the latter 80-40ka, are sources of obsidian in Armenia.

Biome

Bird fauna of Gegham Mountain Range includes about 250 species, what makes 70% of all Armenia's avifauna. The South-Eastern slopes of Gegham mountains contain the

Khosrov Khosrov is a town in the Ararat Province of Armenia. See also * Khosrov Forest State Reserve * Ararat Province Ararat ( hy, Արարատ, ), is a province ('' marz'') of Armenia. Its capital and largest city is the town of Artashat. The pro ...

forest, planted in the 4th century by

Khosrov I Khosrov is a town in the Ararat Province of Armenia. See also * Khosrov Forest State Reserve * Ararat Province Ararat ( hy, Արարատ, ), is a province ('' marz'') of Armenia. Its capital and largest city is the town of Artashat. The pro ...

and converted into a state park in 1958. The Gegham mountains are one of the primary presences of the

vavilovia ''Vavilovia formosa'' is a species of flowering plants in the legume family, Fabaceae. It belongs to the subfamily Faboideae. It is the only member of the genus ''Vavilovia''. It was named after the Russian geneticist, economic botanist, and plan ...

Vavilovia formosa ''Vavilovia formosa'' is a species of flowering plants in the legume family, Fabaceae. It belongs to the subfamily Faboideae. It is the only member of the genus ''Vavilovia''. It was named after the Russian geneticist, economic botanist, and plan ...

'' around Mount Sevsar. Another species '' Poa greuteri'' is endemic in the area.

Rock carvings

A great number of petroglyphs - rock-carvings has been found in the area of Gegham Mountains. Most images depict men in scenes of hunting and fighting, and astronomical bodies and phenomena: the Sun, the Moon, constellations, the stellar sky, lightning, etc. Carvings of birds have attracted some archeological interest.

References

Sources

External links

The Mystery of Azhdahak – the highest point of Gegham Mountains

RockArt in the area of Gegham Mountain Range
{{Authority control Volcanic fields Quaternary lava domes Cinder cones Mountain ranges of Armenia