Consistent grain size distribution of pedogenic maghemite of surface soils and Miocene loessic soils on the Chinese Loess Plateau |
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| Authors: | Junsheng Nie Yougui Song John W King Ramon Egli |
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| Institution: | 1. Key Laboratory of Western China's Environment System, Ministry of Education, Lanzhou University, Lanzhou, Gansu 730000, China;2. Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA;3. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, PO Box 17, 710075, China;4. Department of Earth and Environmental Sciences, Ludwig‐Maximilians‐University, Munich, Germany |
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| Abstract: | There is agreement that ultrafine maghemite grains (<100 nm) are responsible for the magnetic enhancement of Chinese loess. Recent studies show that grain size distribution of ultrafine pedogenic maghemite grains within the aeolian sequences on the central Chinese Loess Plateau deposited in the last 8 Ma is consistent. However, whether the observed grain size distribution of ultrafine pedogenic maghemite grains can be observed in the western Chinese Loess Plateau and modern soils is not entirely clear. Here we find that young surface soil samples across the Chinese Loess Plateau and early Neogene loessic soils from the western Chinese Loess Plateau also show consistent grain size distribution with that of ultrafine pedogenic maghemite grains on the central Chinese Loess Plateau. The fact that young surface soil samples show apparent magnetic enhancement suggests that the ultrafine pedogenic maghemite grains derive from oxidation of ultrafine magnetite grains. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | Loess Plateau magnetic susceptibility ARM Miocene loess maghemite |
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