• •

### 澧阳平原岩板垱剖面地球化学特征与风化强度研究

1. 1.北京大学城市与环境学院 教育部地表过程分析与模拟重点实验室, 北京100871
2.南京信息工程大学海洋科学学院, 江苏 南京210044
3.湖南省文物考古研究所, 湖南 长沙410008
• 出版日期:2013-03-20 发布日期:2013-01-31
• 作者简介:

作者简介：郭媛媛（1983-），女，山东临沂人，博士研究生，主要从事环境演变与环境考古方面的研究。E-mail：yuanyuanguo29@gmail.

• 基金资助:
国家科技支撑计划项目课题（2010BAK67B02）、国家自然科学青年基金（40901012）、国家自然科学基金

### Geochemical Characteristics and Weathering Intensity of the Yanbandang Profile in Liyang Plain, the Middle Reach of the Changjiang River

Yuan-yuan GUO1(), Duo-wen MO1, Long-jiang MAO2(), Wei-min GUO3, Hai-bin GU3

1. 1.Laboratory for Earth Surface Process, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
2. College of Marine Sciences, Nanjing University of Information Science & Technology, Nanjing,, Jiangsu 210044, China
3. Hunan Provincia lInstitute of Cultural Relics and Archaeology, Changsha, Hunan 410008, China
• Online:2013-03-20 Published:2013-01-31

Abstract:

Based on detailed field survey, oxide contents analysis and optically stimulated luminescence (OSL) dating of the samples from the Yanbandang(YBD) profile in Liyang Plain, the geochemical characteristics of major elements, the weathering process and environmental change from late Pleistocene to mid-Holocene were discussed. The results showed that the content of oxide is mainly composed of SiO2, Al2O3 and TFe2O3 (Fe2O3+FeO) and their percentage are between 86% and 90.8%. Compared to the average upper continental crust composition, Na and Ca have been leached out strongly, while total Fe and Mn relatively enriched in the sediments of the YBD profile. The intensity of chemical weathering in the YBD sequence was significantly higher than that of loess and paleosol in Loess Plateau, slightly higher than Xiashu loess in Zhenjiang, almost equal to the Yucheng profile in Liyang Plain, but obviously lower than the red soil from Xuancheng profile in Anhui Province, which indicated a moderate chemical weathering intensity under warm and moist conditions. Changes of the Chemical Index of Alteration (CIA), the Eluvial Coefficient, the Coefficient of Weathering and Eluviations (BA), the Index of Compositional Variation (ICV) and the analysis of A-CN-K and A-CNK-FM ternary diagrams suggested palpable differences in weathering intensity of the strata. There are four stages of weathering process in the YBD profile: relatively stronger weathering, relatively weaker weathering, intensifying weathering, and relatively stronger weathering. The weathering intensity of the yellowish brown soil at the top and bottom of YBD profile were clearly higher than that of the black brown soil and the black soil. Since the chemical weathering intensity is sensitive to climate change, the geochemical parameters can be used to unravel the environmental change to some extent. The higher CIA value reveals that the climate is relatively warmer and wetter in the end of the MIS3a stage. It becomes cooler during the LGM, but gradually returns to be warm again in early-Holocene. The climate in the mid-Holocene was the warmest and most humid compared to the aforementioned periods.

• P595