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.
Wulan County, which belongs to Haixi Mongolian-Tibetan Autonomous Prefecture of Qinghai Province, is located in the central part of Qinghai Province, Haixi Mongolian-Tibetan Autonomous Prefecture and the eastern part of Qaidam Basin, with Gonghe County of Hainan Tibetan Autonomous Prefecture in the east, Dulan County in the south, Delingha City in the west and Tianjun County in the north. The geographical coordinates are 97 °01 "99 °27" east and 36 °19 "37 °20" north. The county is 216.9 km long from east to west and 112km wide from north to south. The total land area of the county is 12858.16 square kilometers. As of 2010, Wulan County has jurisdiction over 4 towns, a total of 38 village (pastoral) committees, with a total population of 36555, including Han, Mongolian, Tibetan, Hui, Tu, Salar and other 17 ethnic groups. In 2010, Wulan County completed its gross domestic product (GDP).