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Relationships between of Sediment Concentrations from ¹⁰Be Analysis and Morphometric Aspect in Sangun Catchment Area, Fukuoka Prefecture, Japan




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DOI:10.17265/2328-2193/2015.04.001

Hendra Pachri, Yasuhiro Mitani, Hiro Ikemi, Ryunosuke Nakanishi and Yoko Saito-Kokubu

Recently, the contributions of slope failures have been difficult to quantify over the time scales of the sediment concentrations in Sangun catchment area, Fukuoka Prefecture. Therefore, to clarify the sources of the sediment mixing in the catchment is important and becomes considering in the future that related the slope failures occurrence. This paper describes how cosmogenic nuclide methods have provided information about the geomorphic process by utilizing ¹⁰Be (half-life = 1.5 ma), measuring the ¹⁰Be/⁹Be ratio, and quantifying ¹⁰Be concentration. The sampled sediments were derived from throughout a drainage basin. To measure the ¹⁰Be/⁹Be ratios in the sediments, quartz minerals were collected from the sediment and then Be was extracted from the quartz. The ¹⁰Be/⁹Be ratios were measured by AMS. We assume that the cosmogenic nuclide concentrations stored in the sediment of a river can increase or decrease, depending on the amount of mixing of sediments during transport through the fluvial system. As results, the 10Be concentrations have been calculated to determine the short term sediment mixing rate in the catchment area. Therefore, the relationship between the morphometrics of the drainage basin, the sediment concentration by ¹⁰Be analysis and the contribution of landslides to landscape changes over timescales of several years have been investigated in Sangun catchment area.

Slope failures, ¹⁰Be concentrations, morphometric, river sediment.