Polar Wander Seminar 古地磁気学・岩石磁気学合同セミナー のご案内



日時:2013年 6月 14日(金)午後6時~7時頃

話題提供:小玉 一人 さん(高知大学)
タイトル:Quantification of magnetic nanoparticles with broadband-frequency magnetic susceptibility measurements: A case study of the loess-paleosol sequence in Luochuan, Chinese Loess Plateau
アブストラクト:Magnetic susceptibility (MS) has been routinely measured, especially in environmental studies, as a magnetic property that reflects the concentration of magnetic substances present in a sample. However, MS is actually a complicating function of many factors, so that MS measurement with more advanced instrumentation and analysis is hoped which could provide information useful in not only magnetic granulometry but many applied fields. In this seminar, I will present a new method capable of estimating a narrow grain size distribution of superparamagnetic (SP) nanoparticles, based on MS measurements over a wide range of frequencies. The proposed method has been tested for a loess-paleosol succession at Luochuan, central Chinese Loess Plateau. Resulting MS frequency spectra show characteristic patterns, which allow assessing the concentration of SP particles in terms of a few magnetic indices. Their profiles show systematic variations that are well correlated with the loess/paleosol stratigraphy, and are associated with high-frequency fluctuations similar to the D-O oscillations for the last glacial-interglacial cycle. These results suggest that the Chinese loess/paleosols may have a huge potential as high-resolution climatic archives like ice cores, cave deposits, and deep-sea sediments.

場所:キャンパスプラザ京都 6階 第8講習室


福間 浩司