丝绸之路天山廊道中段晚全新世环境与古代文明协同演化

Coevolution of late Holocene environment and ancient civilization in the middle of the Tianshan Corridor of the Silk Road

天山廊道古环境变迁与古文明演进的耦合关系是丝绸之路人与自然生命共同体演化研究的重要问题之一。本文对巴音布鲁克湿地泥炭沉积剖面,以花粉作为古气候代用指标,结合花粉主成分分析结果、考古资料,揭示了天山廊道中段晚全新世植被演替历史、环境变化和人类活动演化规律。结果表明:①青铜时期(3877~2697 cal.aBP),花粉组合以荒漠植被为主,PCA轴1得分偏正,PCA轴2得分偏负,气候以冷干为主。人类活动集中于开都河、孔雀河流域。②早期铁器时代至秦汉时期(2697~1756 cal.aBP),荒漠植被花粉含量下降,桦木属(Betula)优势凸显,禾本科(Poaceae)稳中有增,PCA得分与青铜时期相反,气候转变为暖湿。人工驯化类禾本科花粉频现,早期种植业在沙漠边缘绿洲兴起,人类活动中心向西移至轮台县一带。③三国两晋南北朝至隋唐五代十国时期(1756~850 cal.aBP),莎草科(Cyperaceae)、禾本科、云杉属(Picea)花粉含量均增加并达到剖面峰值,湿度变大,进入冷湿期,良好的自然条件使沙漠边缘发育了大片绿洲。人工驯化类禾本科花粉稳定增长,农耕文明进一步发展,为人类生产生活提供了稳定的物质资料,人类活动中心转移至库车河、渭干河流域。

The relationship between paleoenvironment and ancient civilization evolution of the Tianshan Corridor is one of the important issues in the study of the community of life for human being and the nature of the Silk Road.Taking the peat sedimentary profile of the Bayanbulak basin as research material,using pollen as proxy index of paleoclimate,and combining the results of principal component analysis(PCA)and archaeological data,we revealed the vegetation succession history,environmental change,and human activity evolution in the middle of Tianshan Corridor during the late Holocene.Results show that:(1)during the Bronze Age(3877~2697 cal.aBP),the pollen was mainly composed of desert vegetation,with a positive score for PCA axis 1 and a negative score for PCA axis 2.The climate was characterized by cold and dry conditions.Human activities were concentrated in Kaidu and Kongque River basin.(2)From the early Iron Age to the Qin-Han Dynasties(2697~1756 cal.aBP),the pollen of desert vegetation decreased,Betula had a significant advantage,and the members of Family Poaceae increased.The PCA score was opposite to that of the Bronze Age,and the climate changed to warm and humid.Pollens of humandomesticated Poaceae species had occurred frequently,early cultivation emerged in desert edge oasis,and human activity centers moved westward to the area of Luntai County.(3)From the Three Kingdoms to Tang Dynasty(1756~850 cal.aBP),the percentage of the Cyperaceae,Poaceae,and Picea increased and reached the peak on the profile.The humidity increased and entered a cold-humid period.Good natural conditions favored the development of large oases at the edge of desert.The percentage of human planted crops had increased,and agricultural civilization further developed,providing stable material resources for human production and life.The focus of human activities had shifted to the Kuche River and Weigan River basins.