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.
Chengduo County, which belongs to Yushu Tibetan Autonomous Prefecture of Qinghai Province, is located in the central part of Qinghai Province. It borders Qumalai County in the north and west, Shiqu County in Sichuan Province in the southeast, and Tongtian River in the southwest and Yushu County. It is 160km wide from east to west and more than 209km from north to south, with an average elevation of 4500 meters. The total land area is 15300 square kilometers and the total population is 63000 (2013). There are Wenbao, Labu, Kana, Huema, Baimaima, Ani and other ethnic minorities. There are Gazang Temple, Sehang Temple, Labu Temple, Seba Temple and other tourist attractions in Chengduo County. In 2013, the GDP of many counties reached 1.27 billion yuan, an increase of 8.1% over the same period in 2012. On May 15, 2019, the people's Government of Qinghai Province approved the withdrawal of Chengduo counties from the poverty-stricken counties.