Pedogenesis affecting the Matuyama-Brunhes polarity transition recorded in Chinese loess?  

作　　者：QUO Bin ZHU Rixiang Florindo Fabio PAN Yongxin YUE Leping 

机构地区：[1]Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100101,China [2]Istituto Nazionale di Geofisica,Rome,Italy [3]Department of Geology,Northwest University,Xi’an 710029,China

出　　处：《Chinese Science Bulletin》2001年第12期975-981,共7页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant No. 49425405).

摘　　要：A detailed record of the Matuyama-Brunhes (M-B) transition has been obtained from the loess unit 8 (L8) at Duanjiapo (34.2° N, 109.2° E), Shannxi Province of China. An investigation of the rock magnetic properties using hysteresis loops, thermomagnetic analyses identifies pseudo-single domain magnetite as the main carrier of the rema-nence, with a small contribution from maghemite and hema-tite. The paleo-direction records obtained reveal: ( i ) The M-B transition was recorded in the middle and lower part of L8, and comprises of five fast reversals. (ii) The duration of the M-B polarity transition related to the directional change is about 4800 a. (iii) The virtual geomagnetic pole (VGP) path during the transition is confined over Africa, peaked 90°　away from the sampling site, in contrast with the results obtained from the Weinan loess section. The different VGPs are probably attributed to the pedogenesis.A detailed record of the Matuyama-Brunhes (M-B) transition has been obtained from the loess unit 8 (L8) at Duanjiapo (34.2°N, 109.2°E), Shannxi Province of China. An investigation of the rock magnetic properties using hysteresis loops, thermomagnetic analyses identifies pseudosingle domain magnetite as the main carrier of the remanence, with a small contribution from maghemite and hematite. The paleo-direction records obtained reveal: (i) The M-B transition was recorded in the middle and lower part of L8, and comprises of five fast reversals. (ii) The duration of the M-B polarity transition related to the directional change is about 4800 a. (iii) The virtual geomagnetic pole (VGP) path during the transition is confined over Africa, peaked 90° away from the sampling site, in contrast with the results obtained from the Weinan loess section. The different VGPs are probably attributed to the pedogenesis.

关 键 词：M-B polarity TRANSITION VGP path PEDOGENESIS loess. 

分 类 号：P531[天文地球—古生物学与地层学]