皖南网纹红土的剖面风化特征及其古气候意义  

The Weathering Characteristics of the Reticulate Red Clay in Southern Anhui Province and Its Paleo-environmental Significance

作　　者：许良峰[1] 魏骥[1] 姜伟[1] 

机构地区：[1]上海大学环境科学与工程系,上海200072

出　　处：《土壤通报》2010年第1期7-12,共6页Chinese Journal of Soil Science

基　　金：国家自然科学基金"长江中下游网纹红土的多元成因及古气候意义"(40571067)

摘　　要：气候变化下土壤物质过程的响应特征是全球变化研究的重要主题。选取安徽宣城剖面,通过元素分析,对其风化强度特征进行了研究。结合与黄土高原第四纪黄土、古土壤、江苏镇江下蜀土以及江西九江红土等典型风成堆积剖面的对比分析,得出以下结论:(1)宣城红土剖面经历了高强度的化学风化作用,长石损失殆尽,进一步的风化作用已导致其含K矿物(黑云母、伊利石和钾长石)的分解,次生粘土矿物以高岭石为主。此外,宣城红土与其他剖面相比,显著强于镇江下蜀土,远强于洛川黄土与古土壤,而与九江红土的风化程度较为相近。(2)在地形、母岩等条件相似的情况下,气候(特别是温度和降水量)是控制化学风化程度的主要因素,并且与温度相比降水因素可能起着更为重要的制约作用。(3)在地质历史时期,宣城→镇江→洛川,随着地域的北移,气候环境向干冷方向发展。(4)BA,Na/K和硅铁铝率的剖面变化特征揭示,中更新世早、中期,气候相对温暖潮湿,之后气候总体恶化,向干冷方向发展。但在此过程中,伴随着大姑-庐山间冰期和末次间冰期的到来气候又出现过两次短暂的回暖过程,并且在晚更新世早期呈现兼有干湿交替的特征。The soil responses to climatic changes are key problems in the studies of global change.Soil in the past provided a valuable record for the understanding of the relationship between the soil and the climatic changes.The preliminary results of this study suggest the climate-induced geochemical variations of a red earth profile in Xuancheng,Anhui Province.Compared with quaternary loess-palesol and the Xiashu loess profile in Zhenjiang,and the aeolian dust red earth in Jiujiang,Jiangxi Province,the following conclusions were abtained：（1） The Xuancheng red earth profile underwent advanced chemical weathering,which was stronger than that of the Xiashu loess profile,much stronger than that of the loess and palesol in Luochuan,and similar to that of the aeolian dust red earth in Jiujiang.The feldspar loss danger,and the K mineral （black mica,illite and K-feldspar） was decomposed by the further weathering,and the secondary mineral was Kaolinite primarily in the Xuancheng red earth profile.（2） The climate condition,composed of the mean annual temperature and annual precipitation,imposed important influence on the geochemical environment.It seems that the latter was more important than the former.（3） In the geologic history,Xuancheng→Zhenjiang→Luochuan,along with the region moving to north,the climate environment developed to the biting cold direction.（4） The characteristics of weathering intensity of the Xuancheng red earth profile revealed that the climate was warmer and wetter at the early-middle stage of the Middle Pleistocene,then the paleoclimate generally became drier and cooler.Along with the two interglacial stages,the paleoclimate became warmer and wetter twice transitorily.At the early stage of the Late Pleistocene,the paleoclimate was the feature of an alternated dry and wet fluctuation.

关 键 词：第四纪研究 宣城红土 元素分析 风化强度 古气候 

分 类 号：S151[农业科学—土壤学]