萨拉乌苏河两岸宋(西夏)元前后的环境变化与人类活动

Environmental Changes and Human Activities on Both Sides of Sarah Wusu River,in Song(Xixia)and Yuan Dynasty

根据对萨拉乌苏河两岸地层时代、古代遗址分布、剖面孢粉分析、考古资料、古文献和前人研究成果的综合分析,结合野外考察资料的研究,认为除气候因素外,萨拉乌苏河的下切也是两岸地貌水文情况变化、植被变化、沙漠化和人类活动兴衰值得考虑的原因。萨拉乌苏河现在的深切河谷在唐代中后期才开始下切形成,之前附近为较大面积的湖沼水域,水域内人类活动程度较低。萨拉乌苏河下切使两岸在宋元时期形成了一个适于牧业经济方式的茂盛的草原湿地环境,造成宋元时期该流域人类活动的繁荣局面。而元代以后该河流的下切深度过深引起的水文条件的退化与气候变化、人类活动影响等因素的叠加,也是导致其两岸环境恶化和人类活动衰退以及明代后期沙漠化事件的重要原因。

Based on comprehensive analysis of the stratigraphic age,ancient ruins distribution,pollen analysis nearby Sarah Wusu River and archaeological information,ancient literature about this river,combined with field investigation,the authors found that the geomorphology hydrologic situation,vegetation,desertification and human activities have changed a lot on both sides of Sarah Wusu River since the Tang Dynasty.These changes are the results of both downcutting and climate change of Sarah Wusu River.The deep valley of Sarah Wusu River began to form after mid and late Tang Dynasty,and there were few lakes with almost no human activities before that time.The downcutting of Sarah Wusu River formed wetlands environment on it’s both sides in the Song and Yuan Dynasties which was suitable for the lush pastoral economy,resulting in prosperity of human activities.After the Yuan Dynasty,the depth of the river was too deep,causing the deterioration of the hydrological conditions.Along with climate change and human activities,it led to decline of environment and human activities.It was also an important reason for the desertification event in late Ming Dynasty.