关键词: 蓟城, 晚更新世晚期, 全新世, 环境演变, 地貌

Abstract: The Guanganmen area is the locality of the ancient Jicheng city (the earliest city site in Beijing). Based on the geomorphological analysis and the several kinds of experiments for the samples collected from the geotechnical profile in the construction site of Guangyi Building in Guanganmen area, the reconstructions of palaeogeomology in this area were conducted. The results show that the location of the ancient Jicheng city was just the highland, which developed since the Holocene, beside the river, where the channel of Yongding River has been passed through about 22000 years ago. The climate in this area has changed from the cool and wet environment (sparse-wood grassland was developed) and the following arid environment (grassland vegetation was developed) in the late Late-Pleistocene to the warm and wet environment (sparse-wood grassland was developed) and the following cool and wet conditions (meadow vegetation was developed) during the Holocene.

Key words: Jicheng, late stage of Late-Pleistocene, Holocene, environmental evolution, geomorphology