<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>Luminescence dating has been applied to volcanogenic outburst flood sediments (Takuma gravel bed) from Aso volcano, Japan, and tephric loess deposits overlying the gravel bed. The poly-mineral fine grains (4–11 μm) from loess deposits were measured with pulsed optically stimulated luminescence (pulsed OSL) and post-IR infrared stimulated luminescence (pIRIR) methods, whereas the Takuma gravel bed containing no quartz, was measured with IRSL and pIRIR methods using sand sized (150–200 μm) plagioclase. The loess deposits date back at least to ∼50 ka by consistent IRSL, pIRIR and pulsed OSL ages from the lowermost part of the loess deposits from one section. The ages obtained from the bottom part of the other loess section are not consistent each other. However, we consider that the pIRIR age (72±6 ka) which showed negligible anomalous fading is most reliable, and regard as a preliminary minimum age of the Takuma gravel bed. The equivalent doses (De) for the plagioclase from the Takuma gravel bed have a narrow distribution and the weighted mean of the three samples yield an age of 89±3 ka. This age is in agreement with the last caldera-forming eruption of Aso volcano (∼87 ka) and it is likely that the pIRIR signal has not been bleached before the deposition. IRSL dating without applying pIRIR using small aliquots was also conducted, however, the IRSL signal shows no clear evidence of an additional bleaching during the event of outburst flood from the caldera lake.</p></abstract>

Luminescence dating has been applied to volcanogenic outburst flood sediments (Takuma gravel bed) from Aso volcano, Japan, and tephric loess deposits overlying the gravel bed. The poly-mineral fine grains (4–11 μm) from loess deposits were measured with pulsed optically stimulated luminescence (pulsed OSL) and post-IR infrared stimulated luminescence (pIRIR) methods, whereas the Takuma gravel bed containing no quartz, was measured with IRSL and pIRIR methods using sand sized (150–200 μm) plagioclase. The loess deposits date back at least to ∼50 ka by consistent IRSL, pIRIR and pulsed OSL ages from the lowermost part of the loess deposits from one section. The ages obtained from the bottom part of the other loess section are not consistent each other. However, we consider that the pIRIR age (72±6 ka) which showed negligible anomalous fading is most reliable, and regard as a preliminary minimum age of the Takuma gravel bed. The equivalent doses (De) for the plagioclase from the Takuma gravel bed have a narrow distribution and the weighted mean of the three samples yield an age of 89±3 ka. This age is in agreement with the last caldera-forming eruption of Aso volcano (∼87 ka) and it is likely that the pIRIR signal has not been bleached before the deposition. IRSL dating without applying pIRIR using small aliquots was also conducted, however, the IRSL signal shows no clear evidence of an additional bleaching during the event of outburst flood from the caldera lake.

Luminescence dating of volcanogenic outburst flood sediments from Aso volcano and tephric loess deposits, southwest Japan

Leibniz Institute for Applied Geophysics, Stilleweg 2, Hannover, D-30655, Germany

Research Institute for Natural Hazards and Disaster Recovery, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata, 950-2181, Japan

Faculty of Education, Kumamoto University, Kurokami 2-40-1, Chuo-ku, Kumamoto, 860-8555, Japan

Geochronometria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Luminescence dating has been applied to volcanogenic outburst flood sediments (Takuma gravel bed) from Aso volcano, Japan, and tephric loess deposits overlying...

Luminescence dating of volcanogenic outburst flood sediments from Aso volcano and tephric loess deposits, southwest Japan

Pubblicato online: 27 set 2013

Pagine: 294 - 303

DOI: https://doi.org/10.2478/s13386-013-0135-4

Parole chiave
IRSL, post-IR IRSL, tephric loess, Takuma gravel bed, Aso volcano, volcanogenic out-burst flood

© 2013 Silesian University of Technology, Gliwice, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Luminescence dating of volcanogenic outburst flood sediments from Aso volcano and tephric loess deposits, southwest Japan

Pubblicato online: 27 set 2013

Pagine: 294 - 303

DOI: https://doi.org/10.2478/s13386-013-0135-4

Parole chiaveIRSL, post-IR IRSL, tephric loess, Takuma gravel bed, Aso volcano, volcanogenic out-burst flood

© 2013 Silesian University of Technology, Gliwice, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
IRSL, post-IR IRSL, tephric loess, Takuma gravel bed, Aso volcano, volcanogenic out-burst flood