甘肃天水地区中新世古土壤的微形态特征及其古环境意义  

MICROMORPHOLOGICAL CHARCTERISTICS OF MIOCENEPALAEOSOL AND THEIR PALEOENVIRONMENT SIGNIFICANCES IN TIANSHUI,GANSU

作　　者：潘美慧[1] 宋春晖[1] 李吉均[1] 张军[1] 张平[1] 惠争闯[1] 

机构地区：[1]兰州大学西部环境教育部重点实验室和资源环境学院,兰州730000

出　　处：《土壤学报》2009年第4期578-585,共8页Acta Pedologica Sinica

基　　金：国家重点基础研究发展计划(973计划)项目(2005CB422001);国家自然科学基金项目(40721061;90211013)联合资助

摘　　要：通过对甘肃天水地区中新世古土壤(孙家剖面的第17～20层古土壤、下山剖面的第79～82层古土壤)微形态、粒度、碳酸钙含量、Rb/Sr、CIW、磁化率和色度指标的综合分析,揭示出该区中新世古土壤发育强度普遍高于当地现代土壤,其中早中新世中晚期古土壤发育程度相对较弱,古土壤类型为森林-森林草原型褐土-碳酸盐褐土,成壤时期气候为湿润-半湿润,指示亚洲季风可能在早中新世中晚期已经出现,强度较弱,但仍高于现代当地季风强度;中中新世古土壤发育程度强,古土壤类型为森林淋溶型褐土至棕壤,成壤时期气候温暖湿润,说明中中新世夏季风可能已很强盛,并且明显高于现在当地季风强度。Comprehensive analysis of the Miocene palaeosol in Qin＇ an area, Tianshui, Gansu, covering micromorphology, particle size, of CaCO3 content, Rb/Sr, CIW, magnetic susceptibility and chroma, revealed the palaeosol was more developed than the modern soil in the region, and of the soils, however, the palaeosol in the middle and late period of the early Miocene epoch was relatively lower in development degree. The soil is Cinnamon soil-Carbonating Cinnamon soil formed in humid/semi-humid forest/forest-steppe environment, suggesting that monsoon already appeared in Asia as early as that period, with intensity, though quite weak, still quite stronger than the modern one. The palaeosol of the middle Miocene was stronger in development degree, and is Cinnamon soil to brown soil formed in warm and humid climate, suggesting that the monsoon prevailed in Asia in that period and was much stronger than the modern ones.

关 键 词：天水地区 古土壤 微形态 古环境 

分 类 号：P934[天文地球—自然地理学] P512.2