Contrasting magnetic properties from two loess/paleosol sections in Gansu Province, west China  

作　　者：Toshiaki Mishima Masayuki Torii H.Fukusawa K.Oi T.Sasaki Y.Ono 

机构地区：[1]Division of Earth and Planetary Sciences, Kyoto University, Kyoto 606-8502, Japan Present address: Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan. [2]Division of Earth and Planetary Sciences, Kyoto University, Kyoto 606-8502, Japan Present address: Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan. Present address: Faculty of Informatics, Okayama University of Science, Okayama 700-0005, Japan. [3]Department of Geography, Tokyo Metropolitan University, Hachioji 192-0364, Japan [4]Graduate School of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan

出　　处：《Chinese Science Bulletin》1999年第S1期181-188,共8页

摘　　要：We made comparison of magnetic property between two loess/paleosol sediments from theBeiyuan section, Linxia and the Shajinping section, Lanzhou. The two sections apart only 100 km inNE-SW direction. At the Beiyuan section, enhancement of the low-field magnetic susceptibility, ARMsusceptibility and SIRM are observed in paleosols. The positive correlations among these threeparameters suggest the presence of two magnetic components, i.e. the background component and theenhanced component. The unblocking curves of low-temperature IRM give strong evidence for the ideaof the two components. On the contrary, the magnetic parameters are almost constant throughout theShajinping section. The enhanced component is not found in the Shajinping section. The magneticproperties of the background component are indistinguishable between the two sections. Contrastingmagnetic properties imply the difference of soil formation process between the two sections.We made comparison of magnetic property between two loess/paleosol sediments from the Beiyuan section, Linxia and the Shajinping section, Lanzhou. The two sections apart only 100 km in NE-SW direction. At the Beiyuan section, enhancement of the low-field magnetic susceptibility, ARM susceptibility and SIRM are observed in paleosols. The positive correlations among these three parameters suggest the presence of two magnetic components, i.e. the background component and the enhanced component. The unblocking curves of low-temperature IRM give strong evidence for the idea of the two components. On the contrary, the magnetic parameters are almost constant throughout the Shajinping section. The enhanced component is not found in the Shajinping section. The magnetic properties of the background component are indistinguishable between the two sections. Contrasting magnetic properties imply the difference of soil formation process between the two sections.

关 键 词：LOESS PALEOSOL magnetic properties environmental MAGNETISM 

分 类 号：P534[天文地球—古生物学与地层学]