甘青文化区新石器文化的时空变化 和可能的环境动力*

气候变化引起的环境系统的变动,可以对史前文化的时空分布产生决定性的影响。甘青文化区是我国古文明发祥地之一。这里新石器文化非常发达,遗址丰富,类型齐全,为一个自成体系的古文化中心。通过分析不同类型的新石器文化的时空分布的变化,发现自大地湾文化至马家窑文化时期,研究区文化在空间上扩张,而后逐步向南退缩。这一变化和气候的干湿状况的变化密切相关。5kaB.P.气候逐步趋向干旱,导致文化分布上的空间差异,至齐家文化时期,研究区105°E以西遗址点的空间分布大大地向南收缩,而105°E以东齐家文化的分布范围和仰韶文化基本一致。

THE TEMPORAL AND SPATIAL CHANGES OF NEOLITHIC CULTURES IN GANSU-QINGHAI REGION AND POSSIBLE ENVIRONMENTAL FORCING

Excellent examples show that climatic perturbations are associated with societal evolution, such as its temporal and spatial distribution. Gansu-Qinghai region is one of the origin areas of Chinese civilization. The earliest known Neolithic Culture in this region is the Dadiwan Culture (7800~7350aB.P.), followed by the Yangshao Culture (6800~4900aB.P.), Majiayao Culture (5300~4200aB.P.), and the Qijia Culture (4300~3900aB.P.). The temporal and spatial analyses based on GIS show the distribution of Neolithic Cultures in this region. Only two sites belonging to the Dadiwan Culture have by far been known, indicating that the region was sparsely populated at that time. Subsequently, the Yangshao Culture emerged between 6800~4900aB.P. and expanded to a regional scale, as indicated by the increasing abundance of archaeological sites. During the middle and late Yangshao Periods, the number of sites increased rapidly and expanded to a larger area than that of either the Dadiwan Culture or the early Yangshao Culture. After 5300aB.P., the Yangshao Culture was succeeded by the Majiayao Culture. The Majiayao Culture lasted for more than 1000 years (5300~4200aB.P.), and is characterized by its elegantly painted pottery. The Majiayao Culture demonstrates a thriving and prosperous society which was characterized by large villages and round or rectangular architectures. The houses are vaulted for storing property, and the pottery kilns are located near the village. In Majiayao tombs, massive funerary objects were found along with abundant millet grains. Another signature of prosperity is demographic expansion which is indicated by the dramatic expansion of archaeological sites of this period. The Qijia Culture (4300~3900aB.P.) superseded the Majiayao Culture. During the Qijia Culture period, the spatial distribution of archaeological sites west to 105°E shrinked to southern part while spatial distribution of sites east to 105°E almost has no changes comparing with the earlier cultural sites. The climatic and environmental contexts make perfect sense to the temporal and spatial changes of those cultures. Pollen record from the Qinghai Lake shows that a warm and humid climate began at the Early Holocene, and reached its maximum at 6.5kaB.P. After 4.5kaB.P. , the climate changed to dry. Pollen record from Dadiwan shows that the climate was humid during 7.4~6.7kaB.P., then changed to semi-arid, and further changed to dry after 4kaB.P. Pollen record of Hongshuihe also shows that it was warm and wet during 7290~6380aB.P. ,followed by frequently fluctuations. During 5720~5070aB.P. , it was still humid, but later changed to dry. This climatic trend is consistent with the temporal and spatial change of Neolithic Cultures in Gansu-Qinghai region. It is clear that cultural evolution is not only forced by regional scale environmental change but also by the long time scale climate change.