Wind erosion Gobi

Wind erosion Gobi

Wind erosion Gobi refers to the open area which is mainly composed of gravels and distributed in the edge of basins and valleys in arid areas. Sands on the top or the middle of the fan are blown away by winds, leaving the gravels behind. Thus, the wind erosion Gobi is formed with the flatter surface, whose slope angle is 5 ° to 10 ° (Mingzhong Tian, 2009).

During early Pleistocene period, the south Qilian Mountain, the Altun Mountain strongly rose, making the Dunhuang Basin relatively subside. It is not until the Pleistocene that the thick lacustrine deposition is deposited, which is composed of the conglomeratic coarse sand, gravel, sandy loam, sage green sand, mud and gravel. When it comes to the late Pleistocene, the basin gradually rose, and the Lop Nor became dry, making the strata of lacustrine facies above the surface. Torrent from Beishan and Shule River contribute to the formation of diluvial fan and its deposits. Blown by wind for a long time, sands are blown away, and gravels are left, forming today's black Gobi (Figure 4-6). 

Figure 4-6 Black Gobi

Figure 4-7 FengLingShi

There are large amounts of FengLingShi (figure 4-7) in the Gobi, which refer to the rocks spread on the desert or the Gobi. Smooth surface edges or corners are formed as a result of the long-term erosion by the wind and sand. The edge surface is usually in line with the wind direction. FengLingShi is a kind of unique ornamental cultivars in northwest China, which are mainly distributed in arid desert region with dry climate. It is the masterpiece formed by wind erosion and abrasion of the ground material. There are a lot of FengLingShi on the Gobi desert in the Yardang scenic area within the park, the edge surface of which is regularly distributed. Most of them are in the direction of north or east while there seldom are in the direction of south, which can reflect that the dominant direction of the wind is north and east within the area.  FengLingShi surface has a layer of paint, which is formed on the surface of rocks as a result of the evaporation of water due to the increasing groundwater level in the arid desert where the Gobi bedrocks are bare. It is a layer of thin film of red brown iron oxide and black manganese oxide, which is like a layer of paint and thus is named desert paint.