Most of the lakes in Ali area of Xizang belong to the tectonic,faulted ones.At the end of the middle Pleistocene the violent tectonic movement caused faulted zone accompanied with rift and hydrothermal activity.The spring water abounding with boron and lithium continuously flowed into the lakes.With uplifting of the plateau,the climate within the plateau became drier,and leaded the withdrawal and lowering of the water level of the lakes.Up to the early Holocene,the climate became more anal more dry.The concentration of the lacustrine water brought about the enrichment of soluble salts.The solonchaks in this area are developed from the deposits of the lake terraces Ⅰ and Ⅱ formed in Holocene.