宁镇地区中更新世环境演变的沉积学研究

句容放牛山剖面ESR测年、粒度以及磁化率的研究结果表明,下蜀黄土作为一种受后生成土作用强烈的风尘堆积,其性状与北方黄土差别很大,主要表现为由于成壤作用及次生风化作用导致粘粒含量增多。该剖面揭示出本区中更新世 5个气候暖湿期,分别是 :15 9~ 16 3ka,192ka,195~ 198ka,2 0 3~ 2 30ka与 311~ 35 0ka。其中第一个相对暖湿期不十分明显,在大致同时期的深海氧同位素 (V2 1- 14 6孔 ) 6阶段当中为一个小的气候回暖波动,第 2、3、4气候暖湿期可大致与西峰黄土S2古土壤层所反映的气候温暖事件相对应,可与深海氧同位素 (V2 1- 14 6孔 )第 7氧同位素阶段大致相对比。其中,前 4个温暖期可大致与老虎山下蜀黄土的标准剖面自上而下的 4个埋藏古土壤层相对应。旧石器考古发掘发现 6、7层有石器,从剖面测年资料及各环境代用指标综合分析得出,当时为暖湿的生态环境(即第 5个气候暖湿期 ),较适宜人类活动,与南京汤山猿人洞研究结果相一致。东北地区庙后山下层文化 (14 0 0~2 30ka)以大石片石器为主,文化面貌兼有华北大小两个石器系统的特征。这与该遗址发掘的石器相类似,这可能说明至少在中更新世中期长江河道应在句容以南。

Sedimentological Record of Environmental Evolution in the Mid-Pleistocene in Ningzheng Area

ESR dating, grain size and magnetic susceptibility measurements indicated that there exists a great difference in properties between the Xiashu loess, a kind of aeolian sediments, and the loess in the north China.The evidence showed that there are more clay particles in the Xiashu loess. Kd, frequency-dependent susceptibility and other environmental indicators suggested 5 relatively warm and humid climatic periods in the mid-Pleistocene: 159～163ka,192ka,195～198ka,203～230ka and 311～350ka. The first warmer climatic period was corresponding to the slightly relative warmer climatic period shawed in the deep-sea oxygen isotope (V21-146 hole) stages 6 and the 2~ nd , 3~ rd and 4~ th warmer climatic periods were corresponding to the warmer climatic event reflected by S2 and to the marine oxygen isotope stage 7. There existed a good relation between the four buried palaeosol layers of Laohushan Xiashu loess section and the four warm, humid climatic periods of the Jurong section. Paleolithic excavation shows a certain amount of stone implements in the 6 and 7 layer, indicating human activities at that time. Magnetic susceptibility and grain-size records suggested a warm and humid environment at that time, which was suitable for the human activity. And, this was in good agreement with the research result from pithecanthrope cave of Tangshan in Nanjing. The stone implements of the Miaohoushan culture in North east China were similar in features to those from North China and Jurong Paleolithic site, probably suggesting that the channel of the Yangtze River used to lie in the south of Jurong, Ningzheng Region.