Historical, geological and remotely sensed evidences of the Holocene environmental evolution of hydr

• 作 者: Qin Xiaoguang
• 机 构: Institute of Geology and Geophysics, CAS
• 出 处: 干旱半干旱环境对地观测国际会议
• 发表日期: 2012年7期

Historical records show that there were more than 36 ancient oasis kingdoms,a lot of rivers including the north and the south branches of the ancient Tarim river,and the ancient Lop Nur great lake in Tarim Basin during the Holocene.However,most of the ancient kingdoms-located oasis had disappeared,many rivers had changed and Lop Nur has also become a salt crust area of thousands square kilometers.Therefore,the Holocene environmental evolution of Tarim basin is important for understanding the future development trend of the basin.In the study,we re-determined the locations of these ancient kingdoms,ancient rivers and ancient Nop Lur lake by carefully interpreting remotely sensed images and analyzing historical records.Field evidences have also been collected and several Holocene sediment sections have been studied.It was found that that the environment of Tarim Basin has undergone tremendous changes during the Holocene period.We concluded (1) many rivers originating from the Altun mountains flowed across Takalamagan desert from south to north in past although they disappear in center of Takalamagan desert at present.Many ancient kingdoms distributed along these ancient river channels.Area of ancient Nop Lur lake was over 10000 square kilometers.(2)Ancient Loulan kingdom’s farmland and canals and sediment records demonstrated that the environment in Tarim basin was humid during the Holocene Optimum from ~4kaBP to ~7kaBP (when ancient Nop Nur lake’s area was over 10000km2 and Xiaohe culture developed),after and before ~2kaBP (when Loulan kingdom developed).(3) After ~2kaBP,the environment of Tarim basin became more and more drought.