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.
Ruoqiang County, under the jurisdiction of Bayingoleng Mongolia Autonomous Prefecture in Xinjiang Uygur Autonomous region, is located in the southeast of Bazhou, on the southeast edge of Taklimakan Desert, longitude 86 °45 °E, latitude 36 °~ 41 °23'N. It is bordered by Qiemo County in the west, Yuli County and Shanshan County and Hami City in the north, Gansu Province and Qinghai Province in the east, and Tibet Autonomous region in the south, with a land area of 202300 square kilometers, which is the largest county in the country (about the size of two Zhejiang provinces). The county people's government is stationed in Ruoqiang Town, 894 kilometers away from Urumqi and 444 kilometers away from Korla, the state capital. Ruoqiang County has been the second strategic passage from the mainland to Central Asia and Xinjiang to the mainland since ancient times, and it was also the necessary route of the ancient "Silk Road." The county has jurisdiction over two management committees,