Xinjiang Yardang

Description

The internationally accepted landform Yardang has origin in Uygur language, Xinjiang, China; it was Sven Hedin who made it a formal technical expression in the early 20^th century; it means a weathing landform, mainly ridge-like, castle-like or hill-like in extremely arid region and some basins in arid region with a considerable scale, where the not totally solidified sediment of the Cretaceous period, the Jurassic period and the Tertiary period (especially from the late tertiary period) will be weathered by the wind and runoff.

China is one of the countries in the world with a large area of concentrated Yardangs, about 20,000 km². The most typical Yardangs are particularly concentrated in the basins in Xinjiang and Qaidam Basin in Qinhai Province. Xinjiang, located at the hinterland of Euroasian continent, and sparse rain and abundant wind make convenience for the development over 6,000km² of Yardang. Hami basin, Lop Nur and Junggar basin are where the Yardangs are mainly distributed in Xinjiang, and it is an outstanding example of Yardangs under the temperate continent climate and in the desert of the extremely arid region in central Asia.

The Hami Basin is the largest intermontane lowland fault basin in China where there are large areas of sandstone, mudstone and glutenite of the Cretaceous, Paleogene and Neogene periods. Under the effects of runoff and wind, a number of types of Yardang groups have developed in an area of 2,500km², 120km long and 30-50km wide, which are mainly castle-shaped, ridge-shaped and hill-shaped, and light brown or khaki in color mixed with purple stripes, most of the top covered with 2-4m salt crust. The elevation of Hami Yardangs differs greatly, has various monomer positions and magnificent integral sight. The Yardangs in the Hami Basin provide typical examples of water-eroded gullies and wind-eroded trenches at the early developmental stage, bluff-shaped, castle-shaped, ridge-shaped, and peak cluster at the middle stage and hill relics at the late stage. It is where the largest scaled and best-preserved Yardang with the most types can be found in China.

The Junggar Basin is the second largest inland basin in China with a vast area of Jurassic and Cretaceous sandstone, mud stone and conglomerate, gray-greenish, brown-reddish, amaranth and khaki colored Yardangs have developed on a large scale in Urhe. The landform of this area is formed initially by water erosion and then by the wind force, developed castle-shaped and pagoda-shaped Yardangs, belong the middle stage of Yardang development. Strong winds blow through and across the Yardangs in Urhe throughout the year, making a sound like the wail of a ghost. Thus, Urhe is given the name of ghost city. Urhe is home to hill like Yardangs with the purple reddish, yellow and greyish green colored most popular.

Justification of Outstanding Universal Value

The nomination property shows the most majestic Yardangs landscape cluster in the arid and extremely arid desert regions in temperate zone

The bluff-shaped Yardangs arranged orderly. Dozens of meters high horizontal strata densely and interlaced distributed and developed vertical joint, formed thousands of columnar and coniform orderly arranged majestic bluff forest landscape cluster by runoff and collapse action.

The ridge-shaped Yardangs are imposing. More than a dozen kilometers ridges and grooves alternately arranged, hundred groups of ridge-shaped Yardang landform stretched several tens of kilometers, giving the impression of a large fleet of ships in a vast sea.

The castle-shaped Yardangs have various positions and colors. The strata with alternatively distributed sandstone and mud stone formed various types of wind-erosion castle such as cubic hill shape, round hill shape, temple shape by runoff and wind action, with red, yellow, grey and green colors, made them became majestic colorful Yardang landscape cluster.

Isolated hill relics Yardangs have strange shapes. The most typical ones are tower shape, column shape, beacon tower shape and mushroom shape, and the animal shapes such as eagle, horse, monkey and turtle are vivid as well as the figure shapes such as warrior, peri, old man and child.

The nomination property is the most concentrated, the largest, the most types and the best preserved of its kind in the arid and extremely arid desert regions in temperate zone

Various types of Yardang can be found in the nominated property, such as the cubic hills, teeth-like ridges, etc. at an early development stage, as well as ridge-like shapes, whale back shapes and castle shapes, etc. at the peak stage, and isolated hill relics, pagoda forest shapes, cone-like shapes, etc. at the late stage. The complete process of Yardang landform form and develop is represented.

Furthermore, Xinjiang Yardang includes the four most representative shapes: castles, ridges, bluffs and isolated hill relics, and the landform features and diversity are incomparable. Urhe ghost city Jurassic and Cretaceous strata developed most typical castle-shaped and pagoda-shaped colorful Yardangs initially by water erosion and then by wind action. Hami Yardangs landform belong the early stage of development and developed vertical joint, formed typical bluff cluster shaped Yardang landform, also is the most concentrated, the largest, the most types and the best preserved typical area of its kind in China.

The nomination property is an outstanding example of the environmental changes as well as the geologic and geomorphic processes in the arid and extremely arid desert regions in the temperate zone

Nomination property Yardangs are mainly composed of continental sandstone and mud stone formed in the meso Cenozoic and the Quaternary. The sandstone results in castle-like Yardang and the mud stone forms ridge-like Yardang. The major exogenic forces are weathering, wind erosion, runoff, collapse, etc. In particular, weathering and runoff are active in the early stages, wind erosion is active in the middle stage and collapse occurs in the late stage. The nominated property presents the complete process of Yardang formation from surface weathering at the beginning, the massive landforms at maturity to disappearance at the end. The property presents Yardangs representing the geologic processes of various geographical units, in different stratigraphic sequences, in different development periods, of different types and under various exogenic forces. It is an outstanding example of the on-going geologic and geomorphic process of Yardang construction and destruction, and is the ideal type of Yardang in the world from which the name of the phenomenon has been taken. Furthermore, the stratigraphic sequences constituting Yardang landform recorded the ancient natural geological section under climate change, is an important carrier of studying the Qinghai-Tibet plateau uplift and central Eurasia drying processes.

Criterion (vii): The nomination property presents the most majestic Yardang landscape cluster in the arid and extremely arid desert regions in the temperate zone, including thousands groups of orderly arranged bluff cluster shaped Yardang landform, ridge-shaped Yardang landform like a large fleet of ships in a vast sea, castle-shaped Yardang landform with various positions and colors combinations and isolated hill relics Yardang landform with strange positions, own excellent aesthetic value, interpreting the spectacular beauty of the desolate gobi desert.

Criterion (viii): The nomination property has various types of Yardangs, the complete process from the surface weathering, embryonic states, full development to disappearance is represented on Jurassic, Cretaceous, Palaeogene, Neogene and Quaternary strata. Furthermore, Xinjiang Yardang includes the four most representative shapes: castles, bluffs, ridges and isolated hill relics. Nomination property is an outstanding example of typical wind-erosion and wind and water complex erosion geomorphic processes in the arid and extremely arid desert regions in the temperate zone, reflecting the central Eurasia drying processes, is an important carrier of studying of the Qinghai-Tibet plateau uplift and central Eurasia drying processes.

Statements of authenticity and/or integrity

The nominated area and buffer zone to present the necessary elements of natural beauty, geomorphic features and the geomorphic processes, including castle-like, ridge-like and hill-like Yardangs of great aesthetic importance. Most areas of Xinjiang Yardang are not populated so no human inference is present.

Comparison with other similar properties

Yardangs are found mainly at the edge of deserts in arid or extremely arid regions where there is sparse precipitation, little vegetation and strong wind erosion, such as in the desert in west Asia and central Asia, the Sahara Desert and the Namibian Desert in Africa, the western desert in North America, the west coast desert in South America, etc. China Yardangs are found mainly in basins in north and south Xinjiang Uygur Autonomous Region as well as in the Qaidam Basin in Qinghai Province. The nomination property is where the geomorphic word Yardang originated and it is also the most concentrated area of Yardang around the world. Comparing with the ones in other places, Xinjiang Yardang has various types and geological basis, complex formation mechanism, recorded the central Eurasia drying processes. It is the most typical example in the world of the environmental changes and geomorphic processes in arid and extremely arid desert regions in the temperate zone, and presents combinations of different types of Yardang landforms. It cannot be replaced.