4000aB.P.前后东亚季风变迁与中原周围地区新石器文化的衰落

VARIATIONS IN EAST ASIA MONSOON AROUND 4 000aB.P. AND THE COLLAPSE OF NEOLITHIC CULTURES AROUND CENTRAL PLAIN

4 0 0 0aB .P .前后中原周围地区新石器文化发生了衰落 ,其原因一直存在较大的争议。文章依据前人的研究成果 ,从东亚夏季风锋面降水的穿时性特点初步探讨了这一问题。认为 4 0 0 0aB .P .前后的降温和由地球轨道因素变化引起的全新世东亚季风的长期变化 ,使东亚夏季风降雨带北撤南迁 ,形成中国东亚季风区的一种南涝北旱的环境格局 ,可能是 4 0 0 0aB .P .前后中原周围地区新石器文化的衰落的主要原因。

Significant archaeological transformations that mark the collapse of Neolithic cultures around Central China during the late third millennium B.C. has been recognized widely. However,the causes for their collapse have been in dispute. In this paper,paleoclimatic data are synthesized to show that an interval of sever climatic anomaly occurred around 4 000 aB.P. across much of China,which was synchronous with a climatic event identified at least in northern hemisphere scale. Our syntheses also indicate that this climatic interval not only is one of the several climatic events during the Holocene but also marks the Middle Holocene climatic transition (the ending of Holocene optimum). Based on geological evidences and analysis of relationship between variations in intensity of East Asian Monsoon and the changes in distributional pattern of monsoon-related rain belts in eastern China,it is concluded that this climatic anomaly superimposed on the Middle Holocene transition induced by variation in the Earth's orbit and significantly altered the hydrological regime to generate a sharp contrasted environmental framework of drought in the north and flooding in the south of China,which is mainly responsible for the collapse of Neolithic cultures around Central Plain.