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.
Sakya County, which belongs to Xigaze City, Tibet Autonomous region, is located in the south of Tibet Autonomous region, the central part of Xigaze City and the south bank of the Brahmaputra River. It is bordered by Xigaze City and Bailang County in the east, Dingjie and Gangba counties in the south, Lazi and Dingri in the west, and Xietongmen in the north. The county seat is 150 kilometers away from Xigaze City. The total area is 7510 square kilometers (2010). By the end of 2010, the total population of Sakya County was 47304, of which the non-agricultural population was 5720, accounting for 3.59% of the total population of the county. Sakya County is located between the Himalayas and the Gangdise Mountains, high in the north and south and low in the middle. The highest peak in the territory is 6092 meters above sea level. There are Chongqu River, Shabuqu River and other rivers. Belongs to the plateau temperate semi-arid monsoon climate. The frost-free period is about 110 days, and the average annual temperature is 5 min 6.