青海官亭盆地考古遗存堆积形态的环境背景

黄河上游的官亭盆地在6000 a BP开始有人类活动出现,在盆地内留下了50多处考古遗址。通过野外调查及考古发掘,将官亭盆地内考古遗址的堆积形态分为叠置型遗址(连续的不同类型的文化堆积) 和单一型遗址(一个类型文化堆积)。同时发现,官亭盆地内考古遗址在时空上的分布规律受自然环境的影响显著。黄河阶地在形成过程中,河流持续切割时间比较长,形成的阶地高度很高,是官亭盆地形成叠置型遗址的一个地貌条件。由于气候原因,黄河上游在3700~2800 a BP存在一段洪水频发期,造成人类活动辗转于二级和三级阶地,形成以单一型遗址为主的文化堆积。洪水发生时,人类活动主要在三级阶地;两次洪水之间如果间隔的时间比较长,会有人偶尔在二级阶地上居住。这种二三阶地间的反复迁移,形成同时期文化遗址分布上的“旋回”特征。在官亭盆地,叠置性遗址似乎代表了一种稳定的生活方式,连续的文化传承;而单一型遗址,代表了一种不稳定的生活方式,非连续的文化传承。

Environmental Settings of Archaeological Sites Depositional Processes and Distribution at Guanting Basin

Based on the investigation and excavation, emphasis was placed on gaining an appreciation for post-depositional processes that form and shape site and examining the effects of natural processes on temporal and special patterns of archaeological sites at Guanting Basin. As to the distribution of archaeological sites, the following features are shown after investigation and excavation: (1) the sites transferred vertically on temporal and special patterns; (2) the earliest cultural layer deposited on the second terrace is Majiayao type of Majiayao Culture, suggesting that the ancient men moved to the second terrace at least during 3169-2882 a BC; (3) the number of sites increased abruptly during Qijia Culture period; (4) the human beings repeatedly occupied the second and third terraces during one culture period; and (5) the sites of Qiajia culture on the second terrace were not covered by the successive culture deposit, but were on the third terrace.