运城盐湖湖泊沉积作用与黄土的关系

Since middle Pleistocene, because the water system withered, the loess sequence had formed on the north part of the Yuncheng Basin, Shanxi Province. The river sedimentation in the middle and south parts of the basin had continued to the end of Middle Pleistocene and early Late Pleistocene (14-10ka BP). During Late Pleistocene the loess stratum occurred on the most part of the entire basin. The salt lake situated at the lowest 4th graben in the basin, under the controlling of regional hydrological gradient, there were still lake and river bend environment in early Late Pleistocene (120ka). In Last Glacial period, great loess material had been transported into the lake area to form alluvial plain. In Last Maximum Glacial stage，the marginal area of the salt lake had changed a playa, and two earth layer accumulated in it. At the middle part of the lake the glaubrite soparated out and almost no carbonate occurred. Tthe enrichment glaubrite layer ended before 19360±400 a BP (14C cal. age), this data is corresponding to the dating on the end of Last Maximum Glaciation determined in Australia. In deglaciation stage the peat including that of Younger Dryas occurred at the swale. Following the climate changed to temperature the salt lake had developed. At late Holocene, because the evaporation increased, the mirabilite layer had formed again. At late Holocene the river flowed into the lake area, so the northeast part of the lake changed alluvial plain.

本项目拟对三门期末、黄土堆积速率加快前的山西运城盐湖扩展事件进行研究，探讨其古难А⑶虻刂恃П尘埃辉谝研胁糠忠巴馐笛榈幕∩希栽?30ka以来湖心岩层及上覆地层沉积物，进行盐类物质、磁化率、碳酸岩、碳氧同位素等测定，以及粒度分析，以确定非构造运动背景下，入湖黄土快速堆积时段，进而与深湖期匹配，扩展黄土---古土壤序列概睢