The Alay or Alai Range (; ) is a mountain range that extends from the

Tien Shan The Tian Shan, also known as the Tengri Tagh or Tengir-Too, meaning the "Mountains of God/Heaven", is a large system of mountain ranges in Central Asia. The highest peak is Jengish Chokusu at high and located in Kyrgyzstan. Its lowest point is ...

mountain range in

Kyrgyzstan Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...

west into

Tajikistan Tajikistan, officially the Republic of Tajikistan, is a landlocked country in Central Asia. Dushanbe is the capital city, capital and most populous city. Tajikistan borders Afghanistan to the Afghanistan–Tajikistan border, south, Uzbekistan to ...

. It is part of the

Pamir-Alay The Pamir-Alay is a mountain system in Tajikistan, Kyrgyzstan and Uzbekistan, encompassing four main mountain ranges extending west from the Tian Shan Mountains, and located north of the main range of Pamir. They are variously considered part of ...

mountain system. The range runs approximately east to west. Its highest summit is

Pik Tandykul Pik Tandykul (Tandy Köl, ) is a mountain in the Alay Mountains of Central Asia. Tandykul has an elevation of and is located on the international border between Kyrgyzstan and Tajikistan Tajikistan, officially the Republic of Tajikistan, is ...

(), reaching 5544 m. It forms the southern border of the

Fergana Valley The Fergana Valley (also commonly spelled the Ferghana Valley) in Central Asia crosses eastern Uzbekistan, southern Kyrgyzstan and northern Tajikistan. Encompassing three former Republics of the Soviet Union, Soviet republics, the valley is e ...

, and in the south it falls steeply to the

Alay Valley The Alai Valley is a broad, dry valley running east–west across most of southern Osh Region of Kyrgyzstan in Central Asia. Geography The valley spreads over a length of east–west. It has a width of in the west, in the central part, and i ...

.Алайский хребет

Great Soviet Encyclopedia The ''Great Soviet Encyclopedia'' (GSE; , ''BSE'') is one of the largest Russian-language encyclopedias, published in the Soviet Union from 1926 to 1990. After 2002, the encyclopedia's data was partially included into the later ''Great Russian Enc ...

The southern slopes of the range drain into the Kyzylsuu or Vakhsh River, a tributary of the

Amu Darya The Amu Darya ( ),() also shortened to Amu and historically known as the Oxus ( ), is a major river in Central Asia, which flows through Tajikistan, Turkmenistan, Uzbekistan, and Afghanistan. Rising in the Pamir Mountains, north of the Hindu Ku ...

. The streams that drain the northern slopes of the range are tributaries of the

Syr Darya The Syr Darya ( ),; ; ; ; ; /. historically known as the Jaxartes ( , ), is a river in Central Asia. The name, which is Persian language, Persian, literally means ''Syr Sea'' or ''Syr River''. It originates in the Tian Shan, Tian Shan Mountain ...

, and empty into the Fergana Valley to the north of the range. , , is also a well-known summit. European route E007:

Tashkent Tashkent (), also known as Toshkent, is the Capital city, capital and List of cities in Uzbekistan, largest city of Uzbekistan. It is the most populous city in Central Asia, with a population of more than 3 million people as of April 1, 2024. I ...

–

Kokand Kokand ( ) is a city in Fergana Region in eastern Uzbekistan, at the southwestern edge of the Fergana Valley. Administratively, Kokand is a district-level city, that includes the urban-type settlement Muqimiy. The population of Kokand was ap ...

–

Andijan Andijan ( ), also spelt Andijon () and formerly romanized as Andizhan ( ), is a city in Uzbekistan. It is the administrative, economic, and cultural center of Andijan Region. Andijan is a district-level city with an area of . Andijan is the most ...

– Osh – Irkeshtam crosses the range by the Taldyk Pass. The range is also traversed by Pamir highway. Some imprecise sources seem to use the term for the whole southern curve of the

Tian Shan The Tian Shan, also known as the Tengri Tagh or Tengir-Too, meaning the "Mountains of God/Heaven", is a large system of mountain ranges in Central Asia. The highest peak is Jengish Chokusu at high and located in Kyrgyzstan. Its lowest point is ...

corresponding to the southern border of Kyrgyzstan, to up north until the perpendicular extension known as

Fergana Range The Fergana Range (; ) is a mountain range of the Tian Shan in the Kyrgyz Republic. The length of the range is 206 km, and the average height is 3,600 m above sea level. The highest mountain is 4,893 m above sea level. Geography The Fergan ...

, but strictly speaking the Alay Mountains are strictly north of

, while confusingly, Trans-Alay Range of

Pamir Mountains The Pamir Mountains are a Mountain range, range of mountains between Central Asia and South Asia. They are located at a junction with other notable mountains, namely the Tian Shan, Karakoram, Kunlun Mountains, Kunlun, Hindu Kush and the Himalaya ...

lies to the south of that valley, as well as Turkestan Range and Zarafshan Range at far southwest.

is collective term for many systems above, but not including any of the Pamirs.

Geology

The Alay Range, based on its genetic type, is a horst-anticline formation that emerged during the

Hercynian orogeny The Variscan orogeny, or Hercynian orogeny, was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan ...

. In its western and central parts, tectonic faults run parallel to the mountain, while in the eastern section, they are oriented from south to north. The geological structure of the range is highly complex: *The western and central sections consist of

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

, and

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

deposits with a thickness ranging from 1,500 to 3,000 meters. These include

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, siliceous and carbonaceous schists,

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

, dolomite,

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, porphyry, tuff,

diabase Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-gra ...

, polymictic, and limestone-based conglomerates. *The eastern section features

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

formations up to 3,300 meters thick, consisting of conglomerates, gravelites, and argillites. In some areas (such as the Kichi-Alay and Kaiyndy Mountains), these layers are intruded by

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

granodiorite Granodiorite ( ) is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from gra ...

, and

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a Mount Imeon * Trans-Alay Range

References

Mountain ranges of Tajikistan Mountain ranges of Kyrgyzstan {{Kyrgyzstan-geo-stub