关键词: 西辽河流域, 辽代, 沙漠化, 环境变迁

Abstract: The main part of the plain formed by west Liao river in the east of Inner Mongolia Autonomous Region is occupied by the famous Korqin desert today.But Qi Dan nation rose and established very strong Liao Dynasty in the west Liao river basin and controlled almost the north of China during 10 Century,thus left a lot of historical writings(historical books and travels) and ruins.These historical materials contain a lot of information on natural environment.The historical records and environmental archeology showed that the environment of west Liao river basin was fairly advantageous,and the landscape of this basin was plat sand land covered by grass and sparse woods such as some species of elms,willow and apricot,and there were vast marshland grasslands and many lakes before 1000 A.D..And this superior environment provided favorable condition for rising of Qi Dan nation.These historical records also showed that the environment of west Liao river basin was some worsening at the beginning of 11 Century.Sand dunes were recorded on different part of the basin by several travelers and historical books.The changes of environment and desertification were shown more clearly.The desertification appeared at the end of 10 Century according to these historical records,and the cause of desertification was that the cold north-west wind from Mongolia plateau was strengthened and climate tended to dry.The role of human activities on desertification was the second and locally in the middle ages,but this role was incorrectly emphasized by some researchers as the first position in the early desertification process of Korqin desert,in fact human activities in desertification of Korqin desert have played a important role mainly in recent 300 a.

Key words: west Liao river basin, Liao Dynasty, desertification, environmental changes