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.
Pingba District, a municipal district of Anshun City, Guizhou Province, is located in the central part of Guizhou Province in southwest China. Zhijin County, Bijie City in the north, Guiyang, the provincial capital in the east, Xixiu District in the west, Shanghai-Kunming Expressway, Xiamen-Rong Expressway, Shanghai-Kunming High-speed Railway and other national transportation arteries run through the whole territory, which is an important transportation hub in Guizhou Province and even southwest China. It is known as the "golden corridor in the west and the cultural corridor in central Guizhou". With an area of 999 square kilometers and a total population of 358800 (2013), the government is stationed in Zhongshan South Road, Anping Street. In 2013, the GDP of Pingba District was 7.329 billion yuan, and the fixed assets investment of the whole society was 8.708 billion yuan. Pingba area is located in the typical karst landform area of China, with beautiful natural scenery and simple folk customs, mainly by the Han nationality.