浙江上山遗址剖面记录中更新世以来的环境演变

通过对上山文化遗址的野外勘察、野外采样和室内粒度、磁化率、释光年代(OSL)和AMS14C年代分析,探讨了上山地区地貌演变过程,分析了上山文化形成与发展的环境背景。研究结果表明,中更新世早期,上山地区为河流相砾石层堆积,中更新世晚期173kaBP左右,由于气候和海面变化及其新构造运动的影响,形成了河流的二级阶地。而后阶地上接受风尘堆积,形成了中更新世晚期的网纹红土。晚更新世,粉尘堆积加速,堆积了厚约1m的下蜀黄土。全新世(11.5kaBP-)开始,气候转暖,粉尘堆积速率降低,上山台地上保存有命名为"上山文化"的新石器遗址,其年代为11400￣8600aBP,遗址中发掘出大量陶器和石器工具,并发现有栽培水稻遗存,这是迄今为止长江下游地区发现的最早新石器遗址,是探索该地区农业起源和新石器文化演化具有重要意义的地点。上山台地西侧低地经历了河流相—湖沼相—河流相—湖沼相的地貌过程,并且AMS14C年代表明,西侧水源消亡于距今1000多年,而台地东侧仍有河流流过,表明上山遗址所处地貌位置为靠近河湖水源的河流阶地之上覆有风成黄土的低平台地。

Environmental Change since Mid- Pleistocene Recorded in Shangshan Achaeological Site in Zhejiang

According to field investigations and sampling as well as laboratory analysis of magnetic susceptibility, grain size, optically stimulated luminescence (OSL) and AMS 14C dating of archaeological site profile of Shangshan in Pujiang area, Zhejiang, this paper revealed the process of environmental change since Mid-Pleistocene and discussed the background of Shangshan cultural development. The results show there were fluvial gravel sediments in Shangshan area in the earlier period of Mid-Pleistocene. But at about 173 ka BP of the late period of Mid-Pleistocene, uplift happened in Shangshan area because of the impact of the climate, sea level change and neotectonic action, movement, thus forming the second terrace of the river. Between 173-75 ka BP, the terrace received aeolian sediment, a layer of reticulate laterite about 80-100 cm thick deposited, and developed under a relatively high temperature. A layer of Xiashu Loess about 1.0-1.5 m thick deposited on Shangshan terrace in late glacial, containing 80% of the loessal dust. At the beginning of the Holocene (11500 a BP-), temperature went higher gradually with more precipitation, the pre-historic human moved on the Shangshan terrace (11400-8600 a BP), which may connect the paleolithic culture and Neolithic culture. The lower place to the west of the Shangshan Site has been the two cycles process of the fluvial facies, lake and moor facies, indicating that the water source of the Shangshan pre-history is the river water or lake water. Moreover, two AMS 14C ages indicated the water resource disappeared more than 1000 years at most.