A mesa is an isolated, flat-topped elevation, ridge or hill, which is bounded from all sides by steep escarpments and stands distinctly above a surrounding plain. Mesas characteristically consist of flat-lying soft sedimentary rocks capped by a more resistant layer or layers of harder rock, e.g. shales overlain by sandstones. The resistant layer acts as a caprock that forms the flat summit of a mesa. The caprock can consist of either sedimentary rocks such as sandstone and limestone; dissected lava flows; or a deeply eroded duricrust. Unlike plateau, whose usage does not imply horizontal layers of bedrock, e.g. Tibetan Plateau, the term mesa applies exclusively to the landforms built of flat-lying strata. Instead, flat-topped plateaus are specifically known as tablelands.
Shache is located in the southwestern border of Xinjiang, the northern foot of the Kunlun Mountains, the southern edge of the Pamir Plateau, the middle and upper reaches of the Yeerqiang River alluvial fan plain between the Taklimakan Desert and Buguri Desert, with a total area of 9037 square kilometers. it has jurisdiction over 32 townships (districts and streets), 485 administrative villages and 73 communities, with a registered population of 870000. There are more than 20 ethnic groups, including Uygur, Han, Hui and Tajik, and ethnic minorities account for 96.3% of the total population. Shache has a history of more than 3000 years. It has become a famous tribal country in the Western region for several times, successively known as Shache, Qusha and Yeerqiang Khanate, which is the focal point of the ancient Silk Road and an important place for military garrison. It is a famous historical and cultural city with the integration of humanistic landscape and natural landscape, Central Asian culture and Western culture.