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.
Guanghe County, which belongs to Linxia Hui Autonomous Prefecture of Gansu Province, is located in the southwest of central Gansu Province, southeast of Linxia Hui Autonomous Prefecture, Dongxiang Autonomous County in the north, Hezheng County in the west, Kangle County in the south and Lintao County in Dingxi City in the east. The total area is 538 square kilometers (2013). It has jurisdiction over 6 towns and 3 townships, with a total population of 215600 (2013). Hui and Dongxiang account for 97.5% of the total population. In 2007, Guanghe County achieved a GDP of 642 million yuan. Guanghe is an agricultural county with poor mineral resources and frequent natural disasters such as drought and hail. it is a national and provincial key county for poverty alleviation and development. Guanghe County has famous scenic spots such as Shuiluan Cave, "New Matthew", Ancient Prince Temple, Qijiaping site and so on. In November 2019, Guanghe County was named "four"