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.
Gaoqing County, which belongs to Zibo City, Shandong Province, is located in the Lubei Plain and the northern end of Zibo City, with a total area of 831 square kilometers. As of 2018, Gaoqing County has a total registered population of 369900; there are 25 ethnic minorities such as Miao, WA, Yi, Zhuang, Hui, Manchu and Mongolian in Gaoqing County. As of 2018, Gaoqing County has jurisdiction over 2 streets and 7 towns, and the county government is stationed at 81 Huanghe Road, Tianzhen Street. In 37 (1948) April, Gaoyuan, Qingcheng two counties merged into Gaoqing County, Li CPC Bohai Office. On January 1, 1990, Gaoqing County was assigned to Zibo City. Gaoqing County is located in the south of North China Plain depression (Ⅰ structure) and Jiyang depression (Ⅱ structure). It is a part of a large sedimentary basin. The terrain is high in the west and low in the east, tilting from northwest to southeast.