北京环境考古

人类居住场所和生活方式受环境的显著影响。30,000年以来北京环境演变可分作6个阶段。旧石器晚期在干寒的环境下,古人类依洞穴而居。到新石器时代之初,气候变暖,有人类活动于山间谷地。后来,直到商、周时期,气候暖湿,人类多在山前台地上生活。到战国至西汉,气候明显变干变凉,人类向泛滥平原转移。北京的先民居住场所迁移的总趋势是,由山地而平原,由台地而低谷。农业兴起于新石器时代早、中期的山前二级台地上,发达于历史时期的低谷地带。北京城的兴起,地利起了重要作用。

ENVIRONMENTAL ARCHAEOLOGY IN BEIJING

A study of prehistoric environment in Beijing area, lying between the central plain culture and northern culture, could reveal the origin of this culture and the origin of Beijing city. This study could be also useful to explain the present environmental problems. Beijing plain, located between the western coast of the Pacific Ocean and mountains in the northwestern and northeastern has undergone environmental changes that can be divided into 6 stages in last 30,000 years. (1) 30,000-23,000 aB. P. Picea and Abies forest grew in Beijing plain, and the fauna containing Coelodonta antiquitatis etc., that indicated a wet and cold climate. Limnologic sediments well developed under this climatic conditions. (2) 23,000-13,000 aB. P. The flora consisted mainly of Artemisia, Chenopodiaceae and Gramineae, but no forest. This indicated a dry and cold climate that is also confirmed by rapid loess deposition in Beijing area. (3) 13,000-11,000 aB. P. The vegetation of Picea and Abies expanded again, with Tilia pollen increasing. The climate became warmer and fluvial deposits formed near the rivers. (4) 11,000-7,500 aB. P. Pinus pollen increased; the climate changed from cool and dry to warm and wet. Rivers and lakes were well developed. (5) 7,500-2,500 aB. P. Broad-leaf trees represented by Quercus increased and the fauna represented by Elaphurus dividianus menjieianus were rich. All above indicated a warm and wet climate, and lakes and bogs were numerous. (6) 2,500 aB. P. —Present. Broad-leaf trees decreased and Pinus increased. Elaphurus dividianus menjieianus gradually disappeared. The climate became cool and dry. Numerous lakes and bogs disappeared with alluvial sediments developed. During 23,000-13,000 aB.P. loess covered up the earth spread over Beijing plain with 5 meters thickness under dry-cold climate. Then, the climate changed into warm and wet, run-off increased and modern Chaobai River, Wenyu River, Yongding River, Zhu River,Xiaoqing River, Dashi River and Juma River were shaped. Mountain foot alluvial fan and loess platform were cut by these rivers and formed secondary platforms or terraces. Ancient residents, such as prehistoric Shangzhai site, Xueshan site, Liulihe site, lied on lower mountains and hilly land, near river and facing fertile land. There were the beginning and expansion of agriculture. By 2,500 aB.P., the fluvial plain was formed by rivers joining in southeastern part of Beijing plain. As rivers cut down progressively and the climate turned into dry, the lower and wetter plain got dry and formed the first terrace. Ancient peolpe went down and occupied the lower plain. At the early years of the Christian era, West Han dynasty established new counties such as Yinxiang, Xixiang, Lu and Hunong, in the lower plain south, east and northeast of Beijing. The development of Beijing natural environments and human culture during prehistoric and early historic periods made it possible that Beijing city came into being and gradually got the central status of Chinese politics, economy and civilization.