Tuesday, July 19, 2022

Armenian Highlands

 Armenian Highlands. Formation, peculiarity and naming conventions. Also modern problems of naming it.

This subject is quite long so I will divide it in two or three parts. First part is about formation.
For various reasons the core of our planet is very hot. This creates a layer of melted magma which very slowly moves in the upper layers around the core. On the top of this magma layer known as mantle there is the Earth crust on which we live. Earth crust itself is not homogenous. It has cracks and is divided into plates. (1-st image) Armenian Highlands is situated on the Eurasian plate. (2-nd picture)
Due to slowly drifting magma those plates are not static. They are slowly moving by few centimeters per year. After a million years of such a migration plates can move a lot.
The reason why Armenian highlands do exist is the migration of Arabian plate toward North ( 15-20 millimeters per year). When two plates meets each other a contact zone emerges where the Earth crust can be destroyed. This destruction leads to huge volcanoes to erupt. The hot magma pours out from mantle transforming into lavas. Most mountains in Armenian Highlands were volcanoes. The highest one is the Ararat. Many flat lands like Shirak plain are just massive frozen lavas from ancient eruptions. They are numerous such volcanic plains. The Araratian plain. Mush plain might be have same origin. And many others. The volcanic eruptions leads to the increase of land level. But it's not the only reason. Arabian plate is much smaller than the Eurasian so it can't force it to move. As a consequence the Arabian plate moves under the Eurasian plate pushing the whole region to move upward. In this way in very ancient times the Greater Caucasian range formed. But later the process there stopped and now it's going mostly in the Armenian Highlands. Which by the way is the reasons of frequent earthquakes.
It must be noted that most large mountain blocks in Eurasia formed in this way. The mountain formation process is called orogeny .African , Indian plates are moving to North creating Alpes, Tibetan plateau subsequently. During this process a chunk of large plate can go on its own and become minor plate. Like the Anatolian who's contact zone with Arabian plate is known as Taurus range. Zagros and the whole Iranian plateau also formed in this way.
Nevertheless the main place where Arabian and Eurasian plates interacts in more intense way is this Highland. The red line in 3-rd picture .That's why it is rising each year. So the orogeny or mountain formation process is still going. Though fortunately without volcanic eruptions.
In sum from geological point of view the concept of a distinctive Highland makes sense. Especially given the fact that scholars have little doubt about the existence of separate Anatolian plate ( moving to south-west) While recently some proposed the existence of Iranian plate including Iran , Afghanistan parts of Pakistan also.
PS The fourth picture demonstrates those mountain ranges of historic Armenia that formed as a result of two plates hitting each others.

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