Caucasus Mountains

• 1. Introduction

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  The Caucasus Mountains rise between the Black Sea and the Caspian Sea, forming one of the great natural boundaries on earth. At their highest point stands Mount Elbrus, whose summit reaches 5,642 metres above sea level. That is 832 metres taller than Mont Blanc, the highest peak in the Alps and Western Europe. Elbrus is often called the highest peak in Europe, though that claim carries a genuine complication. Whether Elbrus belongs to Europe or Asia depends entirely on where you draw the continental line, and geographers have disagreed on that boundary for a long time. The Caucasus were not only a dividing line between continents. They were a corridor of ancient trade, a crossing point on the Silk Road, a region shaped by colliding tectonic plates and volcanic fire. What explains the immense geological violence that created these peaks? How does the landscape shift as you move from the range's western shores to its driest eastern reaches? And how have people moved through, settled in, and lived alongside these mountains for thousands of years?

• 2. A Range Divided

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  Two distinct chains make up the full Caucasus system: the Greater Caucasus in the north and the Lesser Caucasus in the south, running roughly parallel, about 100 kilometres apart. The Greater Caucasus sweeps west-northwest to east-southeast, from the northeastern shore of the Black Sea all the way to the outskirts of Baku on the Caspian. Where these two ranges converge, a connecting ridge called the Likhi Range joins them. On the western side of the Likhi Range lies the Colchis Plain; on the eastern side sits the Kur-Araz Lowland. To the southeast, the Aras River marks the divide between the Lesser Caucasus and the Talysh Mountains, which runs through the Greater Azerbaijan region. The Lesser Caucasus and the Armenian Highland together form the Transcaucasian Highland. At their western end, that highland merges with the plateau of Eastern Anatolia. The Meskheti Range belongs to the Lesser Caucasus system and includes the Mt. Mtirala area, notable for receiving the highest annual precipitation in the entire Caucasus at around 4,100 millimetres. Mount Aragats, which rises in Armenia, is one of the prominent volcanic peaks found in this southern part of the system.

• 3. Tectonic Origins

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  The Caucasus Mountains belong to the Alpide belt, a vast system that arcs from southeastern Europe deep into Asia and is considered a boundary between the two continents. The mountains were born from a collision. The Arabian plate has been pressing northward against the Eurasian plate, and as the ancient Tethys Sea closed, that pressure forced the Iranian plate between them. The rocks deposited in the resulting basin, from the Jurassic through the Miocene, buckled and folded into what became the Greater Caucasus. That same collision lifted the Lesser Caucasus and ignited the volcanic activity that shapes it today. The two ranges are different in their deep structure. The Greater Caucasus is mainly folded sedimentary rock, primarily Cretaceous and Jurassic formations, with Paleozoic and Precambrian rocks appearing at higher elevations. The Lesser Caucasus is predominantly Paleogene in origin, with a much smaller proportion of Jurassic and Cretaceous material. The initial phase of Caucasus evolution traces to the Late Triassic through the Late Jurassic, during the Cimmerian orogeny, when the region lay at the active margin of the Tethys Ocean. The final uplift of the Greater Caucasus came later, during the Miocene, as part of the Alpine orogeny.

• 4. Fire and Tremor

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  Elbrus and Kazbek, the two most famous summits of the Caucasus, began as Pleistocene-Pliocene volcanoes. Kazbek is no longer active. Elbrus, however, erupted in postglacial times, and fumarole activity has been registered near its summit, meaning the mountain still releases volcanic gases. The Javakheti Volcanic Plateau in Georgia and the surrounding volcanic ranges extending into central Armenia are among the youngest geological features in the region. During the Pliocene, the Armenian highland was flooded by calc-alkaline basalts and andesites. The volcanic zone extends from southern Georgia into Armenia and southwestern Azerbaijan, a landscape of plateaus, lava flows, volcanic lakes, and cones. Seismic activity remains a defining characteristic of the region. Contemporary faulting and crustal shortening generate clusters of earthquakes, particularly in Dagestan and northern Armenia. The Spitak earthquake in December 1988 destroyed the Gyumri-Vanadzor region of Armenia, one of the most devastating events recorded in the region in modern times. The Lesser Caucasus lacks the glacial features common on the Greater Caucasus, reflecting its predominantly volcanic rather than sedimentary origin.

• 5. Extremes of Weather

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  In Sokhumi, Abkhazia, at sea level, the average annual temperature sits at 15 degrees Celsius. On the slopes of Mount Kazbek at 3,700 metres, that figure falls to minus 6.1 degrees. The northern slopes of the Greater Caucasus run about 3 degrees Celsius colder than the southern slopes. Precipitation follows its own geography, generally increasing from east to west. The driest corner is the northeastern Caspian Depression, where annual precipitation falls as low as 250 millimetres. The wettest is the Mt. Mtirala area on the Meskheti Range in Adjara, which records a maximum of around 4,100 millimetres annually. The Western Caucasus receives between 1,000 and 4,000 millimetres per year. Regions in the Eastern and Northern Caucasus, including Chechnya, Ingushetia, Kabardino-Balkaria, and Ossetia, receive between 600 and 1,800 millimetres. The snowfall totals are equally dramatic. In some regions, particularly Svaneti and northern Abkhazia, snow cover can reach 5 metres. The snowiest single location is Mt. Achishkho, which often records snow depths of 7 metres. Avalanches across the Greater Caucasus are common between November and April. The Lesser Caucasus, sheltered from the Black Sea's moisture, sees considerably less snow, with average winter cover ranging from 10 to 30 centimetres.

• 6. Forests, Steppes, and Glaciers

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  At lower elevations on the northern slopes of the Greater Caucasus, oak, hornbeam, maple, and ash forests cover the ground. Higher up, birch and pine take over. The alpine zone begins at around 2,000 metres, and the permafrost and glacier line generally starts between 2,800 and 3,000 metres. The northwestern slopes, including areas in Kabardino-Balkaria and Cherkessia, also support spruce and fir forests. On the southeastern slopes, beech tends to dominate at higher locations. The southwestern slopes feature Colchian forests at lower elevations, with oak, buxus, beech, chestnut, hornbeam, and elm; above those, coniferous and mixed forests of spruce, fir, and beech take hold. On the southern slopes the glacier and snow line starts at 3,000 to 3,500 metres. The Lesser Caucasus presents a different character. Its southern slopes are largely grasslands and steppes rising to about 2,500 metres, and the volcanic zone produces distinctive rock formations across southern Georgia, Armenia, and southwestern Azerbaijan. Biomes across the wider region range from subtropical lowland marshes and forests to highland semideserts, steppes, and alpine meadows, with the semidesert and steppe terrain concentrated mainly in Armenia and Azerbaijan.

• 7. Passes, Trade, and Deep Time

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  Tusheti shepherds in Georgia have practiced transhumance, moving livestock to seasonal grazing grounds, for over 10,000 years. That continuity of human presence reflects how the Caucasus Mountains have never been a simple wall between civilisations but a place people learned to cross and inhabit. The range was a key section of the northern arm of the Silk Road, and specific passes shaped the routes that traders and armies used for centuries. The Jvari Pass, sitting at 2,379 metres, carried traffic above the Darial Gorge on the Georgian Military Road. The Mamison Pass on the Ossetian Military Road stood at 2,911 metres. The Roki Tunnel reached 2,310 metres. At the southeast end, the pass at Derbent was known by two names: the Caspian Gates and the Gates of Alexander. Mount Ağrı, at 5,137 metres, rises just south of the Lesser Caucasus in Turkey and stands as a reminder that the mountains and the cultures they divide do not stop neatly at any political or geographic border.