摘要
通过对宣城向阳中晚更新世沉积剖面的综合研究,认为该剖面与中国北方同时代的黄土—古土壤剖面相比较,虽然长江下游以南地区中晚更新世多个冰期中风成堆积的单层厚度与累积厚度,亦即风成物质的沉积通量与沉积速率均比北方黄土区要小,但它们所反映的气候与环境的变化具有明显的可比性。
A typical deposit section found in our investigation, over 11m in thickness, is located on a hill with an elevation of 45 metres near Xiangyang Village, Xuancheng County, Anhui Province. This kind of hills are widely distributed in the southern part of the lower Changjiang River region.
The investigated section can be divided into fifteen layers of nine formations. From top to bottom the second, fifth, seventh, eighth, tenth, twelfth and fourteenth are red silty clay layers, and others are brown-yellow silty clay layers except the fifteenth, which is alluvial gravel bed, and the layers below the fourth, which are plinthites(Fig. 1).
Based on the analyses of chemical composition, mineral constituent and grain size of the collected samples (Tab. 1 and 2, Fig. 1 and 2), all the red clay layers are paleosols, each paleosol layer was developed after deposition of the underlying brown-yellow silty clay layer and the paleosol between the third and the fourth was absent. But the brown-yellow layers in the section, based on the particle size range and the scanning electron micrographs of fine quartz sands (Photo. 1-4), are considered to be discontinuous eolian deposits. In addition, based on the ESR dating of the eleventh layer and the paleolithicartifacts (Photo. 5-8) found in the section, the authors estimated that the stratigraphic sequence was formed from the end of early Pleistocene to the end of late Pleistocene. Therefore, the result of this study showed that the palaeoenvironmental change in the southern part of the lower Changjiang River region was similar to that of the famous loess plateau of North China since the end of early Pleistocene to the end of late Pleistocene (Fig. 3) except that the palaeo-climate was warmer and more humid in the interglacial periods.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
1991年第2期97-104,共8页
Marine Geology & Quaternary Geology
关键词
风成堆积
环境变迁
安徽
aeolian deposits, environmental change, south of the Anhui Province
