干旱区生态环境知识资源中心

In inland drainage basins, many studies have been conducted regarding the geomorphologic evolution processes in the upper and lower reaches, few of them have been done on the middle reaches, which are the pivotal areas connecting the erosion effects of the upper reaches and the deposition processes in terminal areas. In this study, we presented a millennial-scale study from middle reaches of the Shiyang River and the Shule River drainage basins during the Holocene. Several sedimentary sections are selected to calculate millennial-scale erosion and deposition rates. Results show that the middle reaches of the Shiyang River and the Shule River are characterized by deposition processes in the early and middle Holocene, but erosion processes prevailed during the late Holocene. At the same time, the sedimentary facies, grain size, geochemical proxies and pollen proxies of the sediments from middle reaches of the two drainages were used to complement the erosion and deposition rates, which are good for understanding the environment background during the geomorphologic evolution processes. Besides, the main factor affecting the basin-wide geomorphologic evolution is millennial-scale climate change, and the responses of the middle reaches to climate change are different from those of the upper and lower reaches.