从丰镐到长安——西安咸阳地区都城选址与地貌环境变迁的关系初探

From Fenghao to Chang'an--Preliminary Study on the Relationship Between the Location Selection of Ancient Capitals and the Change of Geomorphic Environment in Xi'an and Xianyang Area

周都丰、镐,秦都咸阳,西汉都长安。几大古都分处西安咸阳地区渭河南北两岸,所在区域地貌环境不同,似乎不同的历史时期都城选址标准各异。另外,这一地区古代聚落的分布及选址,从仰韶文化至秦汉时期也存在着类似的变化。经过研究和分析,西安咸阳一带渭河冲积平原的地貌类型--河漫滩、一级阶地、二级阶地、三级阶地和黄土台塬地带等,形成于不同的地质及历史时期。同一个区域在不同的历史时期有可能属于不同的地貌环境类型。因此,西安咸阳地区古都及古代聚落的主要分布区域,虽然现在看来属于不同的地貌环境,但在其所处的历史时期,均属河边一级阶地的范畴。一级阶地既近水源,又无水患,从来都是都城及聚落建设的最佳选择。

Fengjing and Haojing of Western Zhou Dynasty, Xianyang of Qin Dynasty and Chang’an of Western Han Dynasty were ancient capitals in Xianyang and Xi’an area. The location of above-mentioned capitals belong to the different geomorphic types. In addition, the distribution and site selection of ancient settlements in this area also had also changed similarily from Yangshao Culture to Qin-Han period. The main geomorphologic types of Xianyang and Xi’an area--flood plain, first-grade terrace, second-grade terrace, third-grade terrace and loess tableland were formed during the different geological or historical periods. The same area may have belonged to different geo-morphic types in different historical periods. Therefore, the main distribution areas of the ancient capitals and ancient settlements in Xianyang and Xi’an area, although belong to different geomorphologic environments now, all have belonged to the category of first-grade terrace in their historical periods. The first-grade terrace, close to the water source and free from water disaster, was always the best choice for capitals and settlements construction.