Grain-size evidence for multiple origins of the reticulate red clay in southern China  

作　　者：HUXuefeng ZHUYu SHENMingneng 

机构地区：[1]DepartmentofEnvironmentalScienceandEngineering,ShanghaiUniversity,Shanghai200072,China [2]DepartmentofGeography,EastChinaNormalUniversity,Shanghai200062,China

出　　处：《Chinese Science Bulletin》2005年第9期910-918,共9页

基　　金：This work was sup-ported by the N ational Natural Science Foundation of China(Grant Nos.40101013 and 40325007).

摘　　要：Grain-size distributions of the reticulate red clay in Xuancheng, Anhui Province, and Jiujiang, Taihe and Ganzhou, Jiangxi Province, are analyzed. The results are as follows: (1) Generally fine and uniform, grain-size charac- teristics of the reticulate red clay in Xuancheng and Jiujiang are much similar, with no >2 mm gravels, 0.30% and 1.14% of >63 μm fraction on average, respectively, and 34.65% and 37.20% of 10―50 μm fraction, which is apparently accumu- lated. The patterns of the grain-size distribution curves of the uppermost yellow-brown earth of the profiles in the two ar- eas much resemble those of the loess in northern China and the Xiashu loess in southeastern China, while the patterns of the other layers also apparently show some attributes inher- ited from the above. The grain-size distribution patterns of the quartz separated from the whole profiles in the areas are almost identical, which could also be compared with those of the loess and the Xiashu loess. All the features above reveal aeolian characteristics of the reticulated red clay in these two areas. (2) The reticulate red clay in Taihe and Ganzhou is much coarser than that in Xuancheng and Jiujiang, with high content of >63 μm fraction and relatively low content of 10―50 μm fraction. The variations in grain-size distribu- tions of the profiles are also observed. The grain-size distri- bution patterns of both the original samples and the quartz of the red clay could hardly be compared with those of the loess and the Xiashu loess. All the features above reveal their alluvial or diluvial origins. (3) The multiple origins of the reticulate red clay in the areas reflect the diversity and com- plexity of the Quaternary environment in southern China. The existence of the reticulate red clay with aeolian charac- teristics brings forth objective evidence for the occurrence of large-scale dust deposition in southern China during the Quaternary glacial periods. Further investigation and study on the regional distribution of this kind of the redGrain-size distributions of the reticulate red clay in Xuancheng, Anhui Province, and Jiujiang, Taihe and Ganzhou, Jiangxi Province, are analyzed. The results are as follows: (1) Generally fine and uniform, grain-size characteristics of the reticulate red clay in Xuancheng and Jiujiang are much similar, with no > 2 mm gravels, 0.30% and 1.14% of > 63 mu m fraction on average, respectively, and 34.65% and 37.20% of 10-50 mu m fraction, which is apparently accumulated. The patterns of the grain-size distribution curves of the uppermost yellow-brown earth of the profiles in the two areas much resemble those of the loess in northern China and the Xiashu loess in southeastern China, while the patterns of the other layers also apparently show some attributes inherited from the above. The grain-size distribution patterns of the quartz separated from the whole profiles in the areas are almost identical, which could also be compared with those of the loess and the Xiashu loess. All the features above reveal aeolian characteristics of the reticulated red clay in these two areas. (2) The reticulate red clay in Taihe and Ganzhou is much coarser than that in Xuancheng and Jiujiang, with high content of > 63 mu m fraction and relatively low content of 10-50 mu m fraction. The variations in grain-size distributions of the profiles are also observed. The grain-size distribution patterns of both the original samples and the quartz of the red clay could hardly be compared with those of the loess and the Xiashu loess. All the features above reveal their alluvial or diluvial origins. (3) The multiple origins of the reticulate red clay in the areas reflect the diversity and complexity of the Quaternary environment in southern China. The existence of the reticulate red clay with aeolian characteristics brings forth objective evidence for the occurrence of large-scale dust deposition in southern China during the Quaternary glacial periods. Further investigation and study on the regional distribution of this kind of the red clay will be

关 键 词：颗粒尺寸 红土 网状分布 风化作用 地质环境 

分 类 号：P5[天文地球—地质学]