Some prehistoric
ancient human artifacts, including the stone block, axe, flakes and cores, are discovered on the surface
of terrace-I of Sogo Nur, Ejin Qi,
Inner Mongolia, during geological environmental surveys. Those artifacts are supposed to be Holocene remains. 14C dating of a sample taken from the section of Swan Lake at 70.5 cm below the surface gave an age of 4930±152 a, indicating that the section mainly formed in the Holocene, which is the same as the age of the stone implements found at Sogo Nur. Its record may reflect the climatic features during the activities of the
ancient human species. According to spore-pollen analysis, the climate was generally arid or semiarid during this period. Three climate stages can be distinguished. The lower part of the section shows a somewhat warm-wet climate against the relatively dry background in the early stage. The middle part of the section denotes a period of steady development of the dry environment, representing the most arid and cold stage of the whole section. The upper part of the section shows the trend of increase in temperature and humidity in the late stage.