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.
Gande County is a county under the jurisdiction of Guoluo Tibetan Autonomous Prefecture, Qinghai Province. Gande County is located in 99 °36 °30 "~ 100 °53" east longitude and 33 °33 °34 °24 'north latitude. Maqu County, Gansu Province is bordered to the east, the Yellow River to the south, Dari County and Jiuzhi County to the south, and Maqin County to the west and north. Kequ Town, where the county seat is located, is 526 kilometers away from the provincial capital Xining. The county government is stationed in Dongji Township (Wule). 88 kilometers away from the state capital. Gande County has a population of 33000 (2012), mainly Tibetans, accounting for 95.9% of the total population, as well as Han, Hui, Turkish and other ethnic groups. Gande County has a total area of 7046 square kilometers and has jurisdiction over 8 townships. In ancient times, it was Qiang, Tang belongs to "Zhimo Prefecture", Tubo, Yuan belongs to Tubo, Ming belongs to Heshuote Mongolian regime, Qing belongs to Zhongguoroke thousand households and Shangguoroke hundred households.