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.
Shaanxi District, which belongs to Sanmenxia City, Henan Province, is located in the west of Sanmenxia City, bordering Mianchi County in the east, Lingbao City in the west, Ganshan and Luoning County in the south, and the Yellow River and Pinglu County in the north. Sanmenxia city and lakeside area are surrounded on the east and southwest. In 2017, it covers an area of 1609.73 square kilometers and has jurisdiction over 4 towns and 9 townships with a total population of 350100, with an annual GDP of 21.8 billion yuan. Shaanxi has a warm temperate continental monsoon climate, with high topography in the south and low in the north, east and west. Gold, bauxite, coal and geothermal mineral water are listed as the four dominant resources. Longhai Railway, Zhengxi High Speed Railway, Lianhuo Expressway, 209 National Highway and 310 National Highway crisscross in the territory. Famous landscapes include pit courtyard, stone trench ancient road, Kongxiang Temple and so on. The second batch of building a water-saving society