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.
Kaiyuan City, located in the southeast of Yunnan Province, belongs to Honghe Hani and Yi Autonomous Prefecture. Yanshan in the east, Qiu Bei in the south, Mengzi and Gejiu in the south, Jianshui in the west and Maitreya in the north are the traffic fortresses and central cities in southeastern Yunnan. The total area is 1946.91 square kilometers and the population is 334100 (2016). Kaiyuan is rich in coal resources. Xiaolongtan, 20 kilometers away from the city, has lignite reserves of 1.2 billion tons, which is the largest open-pit coal mine in Yunnan, with an annual mining capacity of 6.3 million tons. There is a 600000 kilowatt Kengkou power plant. Cement, chemical fertilizer, sugar, papermaking, wine, food and other industries are beginning to take shape. In 2011, Kaiyuan realized 4.03 billion yuan in industrial added value and 1.19 billion yuan in profits and taxes. In March 2015, Kaiyuan was officially named by the National Association of Love and Health.