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.
Liquan County, which belongs to Xianyang City, Shaanxi Province, is located in the middle of Guanzhong Plain, Jingyang in the east, Qianxian County in the west, Xinping and Xianyang in the south, Chunhua and Yongshou in the north. Between longitude 108o 17040 "- 108o 41m 46" east and latitude 34o 20050 "- 34o 500002" north, with a total area of 1018 square kilometres. Liquan County has been established for more than 2200 years, with 21 ancient cultural sites and 5 ancient buildings, which is one of the 18 key cultural relics tourism counties in Shaanxi Province. Tang Taizong Li Shimin Zhao Mausoleum covers an area of 300000 mu and is buried with 209. it is the largest royal mausoleum in the world. Zhaoling Museum has a collection of more than 8000 cultural relics. Zhaoling Liujun is famous at home and abroad. In 2018, Liquan County has jurisdiction over 1 street, 11 towns and permanent residents.