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.
Dazi District, which belongs to Lhasa City, Tibet Autonomous region, is located in the central and southern part of Lhasa, the middle reaches of the Lhasa River, and the east-west Chala Mountains and Guogalari Mountains in the north and south, respectively. Dazi District, 20 kilometers away from Lhasa, is known as the "East Gate" of Lhasa. The average elevation of the whole region is 4100 meters, the lowest elevation of the river valley is 3730 meters, the annual average temperature is 7.5 ℃, the average annual sunshine is 3065 hours, and the average rainfall is 450mm. The total area of the county is 1373 square kilometers, with an area of 68500 mu of cultivated land. As of December 2017, the region has jurisdiction over five townships and one town, with a total population of 30,000. There are 14 temples and Rizu Lakang in Dazi District, among which Gandan Temple, which was built at the beginning of the 15th century and has a history of more than 600 years, is the first of the six major temples of the Gelug sect of Tibetan Buddhism (Huangjiao).