鄂尔多斯高原距今15 ka以来环境演化

通过鄂尔多斯高原中部折家梁海子湖泊沉积物的粒度、磁化率、色度等环境指标综合分析，探讨鄂尔多斯高原距今15 ka以来的环境演化。鄂尔多斯高原在距今14.3~11.9 ka，深度205~235 cm，为冷干环境；距今11.9~4.0 ka，指标特征反映了降水较为丰富，湖泊扩张，湖泊演化为稳定的深湖环境。潮湿气候环境可能是由于季风活动加剧所致；距今4.0~0 ka，深度85~0 cm，以大幅度波动为特征，表明气候干冷和湿暖交替，风沙发生的频率和强度加强。其中又以距今1.2~1.4 ka期间，深度25~30 cm时气候最为干旱，沉积了较粗的砂，为一强沙尘暴多发时期。 

ON THE ENVIRONMENTAL CHANGES SINCE 15 ka BP IN THE ORDOS PLATEAU

In this paper, the climatic and environmental evolution since past nearly 15 kaBP were revealed by the comprehensive analysis of grain size, magnetic susceptibility and chrominance from lacustrine deposits in the Shejialiang Lake Area, central Ordos Plateau. It''s revealed that during 14.3~11.9 kaBP,at depth of 235~205 cm, depositional environment are dry and cold relatively. 11.9~4.0 kaBP, at depth of 205~85 cm, sediment proxies reflect that abundant rainfall, enlarging lake, and the lake has developed into a stable deep-water condition, wetter climate possibly due to increase monsoon activity. 4.0~0 kaBP, at depth of 85~0 cm, showed that the climatic characteristics were fluctuated by a large margin, that was period of alternate cool dry and warm wet, and the water level of Shejialiang Lake has been fluctuate. That frequency and intensity of sandstorms have strengthened, Including of 1.2~1.4 kaBP,at depth of 25~30 cm, It was one of the driest period, the strong dust storm are frequent, and that deposited coarse sandy layer.