Why does the Gaxun Gobi have salt marshes in its depressions?

The Gaxun Gobi features salt marshes in its secluded depressions primarily due to the region's arid climate and specific geological conditions. In these low-lying areas, the rate of evapotranspiration—the combined loss of water through evaporation from the soil and transpiration from plants—exceeds the limited precipitation received by the desert.12

As water collects in these depressions, it often evaporates, leaving behind concentrated minerals. The soil in the Gaxun Gobi is known to contain gypsum and halite (rock salt), which accumulate as the water evaporates. This process is consistent with the formation of evaporites, where minerals precipitate from brines in areas where water loss outpaces the influx of water from rainfall or other sources. Consequently, these depressions become saline environments that support only salt-tolerant vegetation, such as halophytes, rather than typical marsh grasses.13