Geology of the Ustyurt

The Ustyurt is a low plateau located between the Mangyshlak and the Gulf of Kara-Bogaz-Gol on the Caspian Sea in the west, the Aral Sea and Amu Darya delta in the east. It has a total area of about 200 000 km², with an average elevation of 150 meters. It's highest point rises to a maximum of 365 m in the southwest. It consists of Sarmatian limestones (See below); its edges are separated from adjacent territories by steep scarps, sometimes by vertical slopes, while the surface is flat, stony and gypsiferous. It's chalk rocks make an impressive sight at sunrise and sunset, when the white colour of the rocks are translated into shades of purple. At its margins it drops steeply to the Aral Sea and the surrounding plain. Its most characteristic features is the escarpment known as the Chink', a steep inaccessible slope with the height of about 190 m facing towards the Aral Sea (see picture above).

The dominant landscape is a desert plateau with little no vegetation or water. It once was the bottom of a dried-up sea (Tethys Sea), which existed here in the early and middle Cenozoic era (some 21 million years ago). This is evidenced by shell traces in the limestone, as well as ferromanganese nodules scattered across the plateau which were formed on the bottom of the sea, and then, as more resistant to weathering, left on the surface while other limestone and dolomites were eroded. In places its flat desert terrain broken by chalk deposits in the form of rocks and random cracks looks like the Martian landscape.

The climate is continental and characterized by the coldest winters in Uzbekistan.(up to – 40 degrees C) , summers scorching (+50 degrees C) with heat searing the landscape with low rainfall. There are no permanent surface watercourses. The soils are brown-brown desert, composite soils. The vegetation consists of Anabasis salsa, Artemisia and Haloxylon. The zone is used as distant pastures. Oil and natural-gas deposits lie to the west of the plateau.

The varied flora and fauna of the Ustyurt. include colonies of gerbils, ground squirrels and jerboas and is home to a large number of birds of prey – eagles and vultures. The most interesting animals of the plateau is the endangered saiga and Ustyurt argali. The plateau’s semi nomadic population raises sheep, goats and camels. Also wild horses roam parts of the Ustyurt. Many plant and animal species living on the plateau are listed in the Red Book. Including the central asian tortoise. the sand cat as well as the cheetah, Ustyurt wolf, fox, corsac and jackal. The flora includes different types of polynyas, Anabasis salsa, sarsazan and other medicinal herbs.

ED NOTE: The Sarmatian Stage, major division of Miocene rocks and time (23.7 to 5.3 million years ago). The Sarmatian Stage, which occurs between the Pontian and Tortonian stages, was named for Sarmatia, the ancient homeland of the Sarmatian tribes in what is presently southern European Russia, where important exposures are found. During the Miocene, a number of areas in western Europe became emergent, while sizable areas of eastern Europe were submerged by waters cut off from interchange with the oceans; these isolated, inland seas were freshened by the inflow of streams, resulting in the development of a very distinctive, lagoonal-type fossil fauna represented by peculiar species of clams, gastropods, and bryozoans. These animals were present in great abundance but exhibit little variety; almost no other kinds of animals occur. The bryozoans frequently occur in such local abundance that they form reef like masses. Sarmatian depositional basins fluctuated greatly from extremely salty to brackish.

Ustyurt Plateau

 Illustration: Extent of the Ustyurt 

The Ustyurt Plateau, also spelled Ust-Yurt, Ust-Urt and Usturt (Kazakh: Üstirt, Turkmen: Üstyurt) lays between three Central Asian states of Uzbekistan, Kazakhstan and Turkmenistan.

The Ustyurt plateau in its entirety is some 200,000 square kilometres and stretches from the so-called "Western Chink" between the Gulf of Mangyshlak and the Karynzharyk Desert to the "Eastern Chink" on the west bank of the Aral Sea. It has an average elevation of 150 meters, and consists primarily of stony desert. The plateau’s semi-nomadic population raises sheep, goats, and camels. It also has a number of important Gas fields and production facilties on its perimeter and a growing population.

The Plateau's chalk escarpments, known as "chinks", are hugely impressive and starkly beautiful. The giant terraces stretch hundreds of kilometres to the north and south, reaching heights of up to 219 metres on the border with the Aral Sea, while those on the Caspian rise up to 341 metres high.

The plateau proper consists of a flat, waterless highland plain, covered with sand in some places and with gypsum crystal in others. It is the only place in the world where the Ustyurt urial can be seen. Four plant species and 33 animal species of the Ustyurt plateau are listed in the Red Book of the Republic of Uzbekistan and 40 are on the International Union for Conservation of Nature’s Red List because they are close to becoming extinct.


A type of black saksaul grows only in this region, in the form of proper trees rather than bushes. Relatively large groups of the unique Ustyurt moufflon (a rare type of wild sheep with a reddish coat) and kulan (asiatic wild ass) live on the plateau. As well as a small population of the lynx-like caracal which is threatened with extinction as are dwindelling populations of Indian porcupine, saiga antelope and dzheyran gazelle.

Many reptiles and rodents are endemic to the Ustyurt. Nocturnal animals such as the long-eared desert (Brandt's) hedgehog snuffles through the dark. Apart from the Houbara bustard, the large birds that live here are mainly raptors: the rare Turkmen owl (a subspecies of the Eurasian eagle owl), the Saker falcon, short-toed and golden eagles and scavengers such as the Egyptian vulture.

Every seven to nine years there is a time of glut for these birds when the zhut (a severe blizzard) leaves thousands of hoofed animals dead. This phenomenon, most feared by the local inhabitants, takes place when, after winter rains, temperatures suddenly drop sharply and the desert ground freezes over. Unable to find food, the animals swiftly die.

The continental climate of the region is extreme. Winters are harsh and windy and snow is rare. Spring is short, dry and windy. Summer is hot, cloudless and long lasting. Autumn is warm and long as well.

Annual average temperature is about +10.5 + 11.5°C. Absolute annual minimum temperature is +26 + 34°C; maximum + 43 +45°C; surface heat reaches +60 +70°C. The hottest period is from the middle of July to mid-August. Autumn frosts begin at the end of October, and the spring thaw starts in April.

Precipitation is poor. Annual average precipitation varies from 140-160mm in the north to 90-120mm in the south. Rain showers are common in spring and early summer; washouts and mudslides are common as there is often little vegetation holding the soil together.

Snow cover on the Ustyurt is thin (3-7 cm) and unstable. Not all areas are covered with snow. As a result of the high temperatures in the summer months, poor precipitation and windy weather, evaporation exceeds precipitation by 10-15 times and  humidity a low 40-60%.

Saiga of the Ustyurt Plateau

Photo: Baby Saiga in the snow

The Usturt plateau of Western Uzbekistan and north western Kazakhstan is one of the largest remaining habitats of the Saiga antelope, both the Karakalpak and Kazakh name it the Ak Kuiruk (meaning white tail). It lives on the steeps and semi desert areas of the Eurasian continent and has adapted to survive in the long hot dry summers and cold cold winters.

Traditionally Saiga roam in troops which can number from the hundreds to the tens of thousands. These troops move along with their heads bowed down close to the earth, their hooves raising gigantic clouds of dust. The Saiga has a strange looking nose resembling a proboscis, a result of prolonged evolution which acts as a respirator, so they do not suffocate. On the inside the nose is covered with numerous folds retaining dust. In winter it warms up the frosty air and facilitates breathing.

Saiga antelopes are ideally suited to life on the steppe. The yellowish-chestnut colour of their fleece similar to that of the ground permits the animals to hide themselves from their predators by merging into the environment. New born calves can remain still for a very long time. It is hard to notice a small saiga calf lying motionless on the ground a few metres away. However the young saiga does not stay still for long on the third day after birth it is ready to start on its long journey with its mother.

The saigas breeding season starts in December. During that period of time the bucks fight for the does. Winners collect harems numbering from 5 to 50 does and watch them closely, not permitting them to leave the harem and driving away rivals. They lead a nomadic life migrating many hundred of kilometres each season in search of better pastures. They mostly feed on wormwood and saltwort unfit for other animals, thus maintaining the natural vegetation balance.

Today one of the biggest remaining populations of saiga antelopes is found in the Usturt Plateau of Karakalpakstan where they winter before moving into the Kazakh part of the plateau in search of summer pastures.

Watching the winter migration on the Ustyurt is an impressive sight. On an early frosty morning with the temperature -20 Degrees below Celsius a huge greyish-yellow mass of several thousand Saiga emerge on the horizon. Driven by the piercing wind the animals walk along the snowy plane at a measured pace without ever halting even for a second so as to keep themselves warm.

In ancient times saiga antelopes play an important role in local legends of the people of the plateau. One legend relates about a Shepard whose livestock have all died during a harsh winter. He was dying of hunger when the Almighty sent a Saiga to him saying “I will help save you and your family, provide you with food, show you the best pastures and help you find water and it will always be this way. But remember you must never kill us profit, because we are brothers".

You may only hunt us for the sake of survival.” For centuries people followed the behest. They hunted the saiga without doing any harm to their population. The horns of the bucks used as amulets against disease and evil forces.

As little as a hundred years ago saiga antelopes were considered one of the most numerous hoofed animals in Asia. The numbers of their heard reached millions, and their troops covered Eurasia. It however took man only a few decades to destroy the herds; until only a thousand remained, in small pockets isolated in the remote steeps of Russia, Kazakhstan, Uzbekistan, Turkmenistan and Mongolia.

The cause of the saigas misfortune is their beautiful lyre shaped antlers which are used in traditional Chinese medicine. At the beginning of the 20th century thousands of pairs of antlers where for sale at the markets in Bukhara, Khiva and Tashkent. A pair of antlers costing as much as a camel.

However, only bucks have antlers and they form a minority of the population. When most of the bucks were exterminated, the population lost its natural reproduction ability. Only urgent measures in the early Soviet Period helped them survive at the time. By the 1980s the total population once again reached one million heads and the animals returned to their traditional habitat, and new troops were even able to get acclimatised to new habitats.

The past decades since the end of the Soviet Union have once again proved to be very difficult for these beautiful creatures, the insidious Chinese “medicinal” trade is once again driving the Saiga antelope towards extinction. Just in the last decade alone heard’s in Uzbekistan have reduced by some 90%.

If this immoral trade is not stopped soon there will be little chance of retaining these wondrous creatures for the generations to come.

Source: Wikipedia & Uzbekistan Airlines Magazine - Summer 2009

The Ustyurt Plateau

INTRODUCTION

The Ustyurt Plateau also known as the Ust-Urt and Usturt Plateau. (Kazakh: Üstirt, Turkmen: Üstyurt) . The plateau located between the Aral Sea and the Caspian Sea. It extends roughly 200,000 km²  and consists primarily of stony desert. The plateau’s semi-nomadic population raises sheep, goats, and camels. The Ustyurt is clearly demarcated by its steep escarpments, which reach up to 200m in height called T'chinks.

It is generally a barren and fairly featureless place. In summer, temperatures can reach 42°C and in the winter can fall to -40°C. Coupled with a strong winds it can feel in the summer like being in the permanent blast of a furnace.

The area is inhabited by such rare animals as Usturt Saiga, the moufflon or urial, ratel from the family of martens, long-needled hedge-hog and a good many species of wild cats: karakal, barkhan cat and the famous cheetah and . Birdlife includes  slim gazelles-zhairans, beautiful bustards (or Jacks) and other birds of desert.

The T'Chink

The Ustyurt is an extraordinary natural geological feature, a sand and limestone desert plateau stretching 800km from north to south. It sits on its own micro-tectonic plate or massif which has been gradually elevated over the past four or five million years so that it now stands around 200 metres higher than the delta plane.




Generally the plateau is a slightly hilly desert plain, faintly covered by a wormwood and unprepossessing shrubs of Russian thistle. In wide-spread drainless depressions there also occur shrubs of black saxaul. Steep ledges or (T'chinks) add immensely to the inimitable beauty of the landscape. The western part of the chink is especially picturesque, which achieves 340 meters in elevation; its eroded precipice takes quite fanciful forms. These breakages, formed by the wind, have an almost whimsical character.

To visit the T'Chink you can drive from Nukus to Qon'ırat (Kungrad) and then up onto the plateau or go first to Shomanay and then head northwest towards Shamambet. You will see first the t'chink like some white dream-like apparition along the horizon.

NEARBY WATER BODIES

The Ustyurt (U'stırt) Plateau stretches between the Caspian Sea (left) and the Aral Sea (upper right quadrant). The Plateau is shared between Uzbekistan and Kazakhstan with a small area in the south within Turkmenistan.

There are a number of bodies of water nearby the Plateau. To the lower left of the Map you can see the greenish-blue Karabogas Bay a shallow inundated depression in the northwestern corner of Turkmenistan, a bay on the edge the Caspian Sea, with a surface area of about 14,000 km².

To the east of this can be seen the dark Sarygamysh Lake (salt), situated in north central Turkmenistan with the northwest quarter of the lake in Uzbekistan.

The greenish area to the lake’s northeast is vegetation around the Amu Darya River, which once fed the Aral Sea to its north. Since the Amu Darya and Syr Darya rivers were diverted by irrigation projects, the Aral Sea has shrunken rapidly.

As of 2007 it had declined to around 10% of its original size, splitting into three separate lakes, two of which are now too salty to support fish.

The Aral in 1985


















Main Sources :
http://en.wikipedia.org/wiki/Ustyurt_Plateau
http://www.eosnap.com/tag/sarygamysh-lake/?gtlang=gl
http://www.autoreview.ru

The Aral Sea

ARAL SEA

Photo: Process drying of Aral sea (Interactive map from wikimedia.org)

Millions of years ago, the northwestern part of Uzbekistan and western Kazakhstan were covered by a massive inland sea. When the waters receded, they left a remnant sea known as the Aral.

The Aral as an inland salt-water sea has no outlet being fed by the Amu Darya and Syr Darya Rivers. The fresh water from these two rivers once held the Aral's water and salt levels in balance. However after the 50ies and 60ies when a series of major irrigation schemes were undertaken on the two rivers by Soviet Engineers the water started to recede.

The schemes were based on constructing a series of dams on both two rivers to create reservoirs from which eventially 40.000 km of canals would be dug to divert water to field crops. Afterwards however there was little or no water left in the riverbeds to flow to the Aral Sea. Consequently the water level in the last 50 years in the Aral has dropped by 16 metres (60%) and the volume has been reduced by 75 percent.

Whilst triggering what is considered one of the 20th Centuries greatest ecological disasters; these schemes will not be reversed as irrigated crops are the main source of income and food for millions of people living in the region. The fall in the Aral Sea appears to have slowed, the most recent Google Earth images showed only small changes since ca. 2003.



Photos: NASA satellite images the Aral Sea and part of the lowland section of the Aral basin.