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.
Bortala Mongolia Autonomous Prefecture, referred to as "Bozhou", belongs to Xinjiang Uygur Autonomous region. "Bortala" is Mongolian, meaning "silver grassland". It is located on the northwest edge of Xinjiang Uygur Autonomous region and in the hinterland of Eurasia. the mountains on the west, north and south are continental arid climate in the north temperate zone. With a total area of 27000 square kilometers, it has jurisdiction over 2 county-level cities and 2 counties. The total population in 2018 is 478509. Bordering Kazakhstan, Bozhou has a border of 372 kilometers. It is an important connecting point at home and abroad and a key point for import and export of goods in the "middle channel" of the Silk Road Economic Belt. The second Eurasian Continental Bridge runs through the whole territory. The China-Kazakhstan oil pipeline and the second line of the west-east natural gas pipeline pass through the border. It is the confluence of two major traffic arteries and two ports, National Highway 312 and Provincial Highway 219 and Jingyihuo.