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.
Gar County, located in the westernmost part of Tibet, along the Sengezangbu and Garzangbu basins, is one of the 18 border counties in Tibet. The area is 17197 square kilometers. The cultivated area is 8900 mu. The total population is 42000. It has jurisdiction over 4 townships, 1 town and 11 administrative villages. Gar County is surrounded by mountains, the middle is low and flat, the average elevation is about 4350 meters, and the highest elevation is 6554 meters. There are 12 large and small lakes in the county, of which the larger ones are Langjiu Lake and Xinga Lake. There are three main highways in Gar County, namely, Yeshi Highway, Ari Highway and Hei Highway. The mileage of highways in the country is 498 kilometers. With Shiquanhe Town as the center, Kunsha Airport is officially opened to traffic, and the natural cutting becomes open to traffic. In October 2018, the people's Government of Tibet Autonomous region formally approved that Gar County withdrew from poverty-stricken counties (districts).