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.
Nyingchi is a prefecture-level city under the jurisdiction of the Tibet Autonomous region, known as Gongbu in ancient times. "Nyingchi" is a transliteration of "Niangchi" or "Niangchi" in Tibetan, which means "the throne of the Niang family or the throne of the sun". Located in the southeast of Tibet and the middle and lower reaches of the Brahmaputra River, its west and southwest are connected with Lhasa and Shannan respectively, Jiali County of Naqu City is connected to the west and Changdu to the east, and part of the southern region is bordered by southern Tibet (occupied by India) and Myanmar. It is known as the Jiangnan of Tibet, with the deepest canyon in the world-the Brahmaputra River Grand Canyon and the world's third deepest canyon Palong Zangbo Grand Canyon. Nyingchi has beautiful scenery, many areas are known as "Jiangnan of Tibet", there are Nyingchi Peach Blossom Festival, rich and colorful Nanyi ditch and so on. There are also known as the bottom of Motuo County and Chayu County in Xishuangbanna, Tibet. ...