关键词: 第四纪, 盐湖, 古生态学, 介形亚纲

Abstract: The rainfall in the Chaidamu basin in the Quaternary period was only about one percent of its evaporation capacity under a dry climate. The salinity of Quaternary lakes controlled the geographic distribution of ostracod fauna. In the northwest part of the basin(south from Mt. Argin), it was the polyhaline-hyperhaline water ostracod Eucypris inflate assemblage which had low species diversity of ostracod fauna. In the east and south parts of the basin (north from Mt. Kunlun and west from Mt. Qilian), because of the influence of fresh water river coming from melted snow-mountain water, the assemblage was the fresh-brackish water ostracoda which had high species diversity, furthermore, it was the Qinghaicypris crassa assemblage in Q₁₊₂ and the Candona neglecta-Candoniella lactea assemblage in Q₃₊₄ separarely. During the Quaternary period, large thick deposit accumulated in the rapidly subsided southeast part of the basin in which there were abundant brackish benthons and plankton and a large amount of organic matter. Accordingly, this area is highly rich in natural gas resourse.