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- ItemOptically stimulated luminescence dating of young fluvial deposits of the Middle Elbe River Flood Plains using different age models(Warsaw : De Gruyter, 2014) Kunz, Alexander; Pflanz, Dorthe; Weniger, Tobias; Urban, Brigitte; Krüger, Frank; Chen, Yue-GauIn the last few decades optically stimulated luminescence (OSL) dating has become an im-portant tool in geochronological studies. The great advantage of the method, i.e. dating the deposi-tional age of sediments directly, can be impaired by incomplete bleaching of grains. This can result in a scattered distribution of equivalent doses (DE), leading to incorrect estimation of the depositional age. Thoroughly tested protocols as well as good data analysis with adequate statistical methods are important to overcome this problem. In this study, samples from young fluvial sand and flood plain deposits from the Elbe River in northern Germany were investigated to compare its depositional ages from different age models with well-known historical dates. Coarse grain quartz (100-200 μm and 150-250 μm) and polymineral fine grains (4-11 μm) were dated using the single aliquot regenerative (SAR) dose protocol. The paleodose (DP) was calculated from the DE data set using different ap-proaches. Results were compared with the development of the Elbe River, which is well-documented by historical records and maps covering the last 1,000 years. Depending on the statistical approach it can be demonstrated that depositional ages significantly differ from the most likely depositional age. For the investigated coarse grain quartz samples all ages calculated from the MAM-3UL, including their uncertainties, are within the historical documented age. Results of the polymineral fine grain samples are overestimating the historically documented depositional age, indicating undetectable in-complete bleaching. This study shows the importance of using an adequate statistical approach to cal-culate reliable OSL ages from fluvial sediments. © 2013 Silesian University of Technology, Gliwice, Poland. All rights reserved.
- ItemLuminescence dating of volcanogenic outburst flood sediments from Aso volcano and tephric loess deposits, southwest Japan(Warsaw : De Gruyter, 2013) Tsukamoto, Sumiko; Kataoka, Kyoko; Miyabuchi, YasuoLuminescence 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 deposi-tion. 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. © 2013 Silesian University of Technology, Gliwice, Poland. All rights reserved.
- ItemMethodological Aspects on Luminescence Dating of Fluvial Sands from the Moselle Basin, Luxembourg(Warsaw : De Gruyter, 2010) Cordier, S.; Frechen, M.; Tsukamoto, S.Optically stimulated luminescence (OSL) dating of quartz and infrared-stimulated luminescence (IRSL) dating of feldspar were applied to fluvial sands from the lower terrace (M1) of the Moselle valley in Luxembourg (western Europe). The dating results indicated that the aggradation period for the sediments from below the M1 alluvial terrace can be correlated to the Weichselian upper Pleniglacial (MIS 2), which is in good agreement with the general chronostratigraphy of the Moselle terrace staircase. The ages were obtained from small aliquots of quartz and feldspars, using the single aliquot regenerative (SAR) protocol. The equivalent dose determination included a series of tests and the selection of the Minimum Age Model as the most appropriate statistical model. This made it possible to provide a reliable methodological background for further luminescence dating of fluvial sediments from the Moselle basin.
- ItemIRSL and post-IR IRSL residual doses recorded in modern dust samples from the Chinese Loess Plateau(Warsaw : De Gruyter, 2011) Buylaert, Jan-Pieter; Thiel, Christine; Murray, Andrew; Vandenberghe, Dimitri; Yi, Shuangwen; Lu, HuayuUsing a set of modern/young (0 to about 200 years old) dust samples collected from the Chinese Loess Plateau the bleachability of IRSL measured at 50°C (IR50) and post-IR50 elevated tem-perature IRSL (measured at 225°C and at 290°C) is investigated by measuring the apparent (residual) doses recorded by these signals. Doses recorded by quartz OSL are used as a reference. Allowing for differences in dose rates it seems that both IRSL and post-IR IRSL signals yield residual doses that are significantly larger than the doses measured in quartz. These residual doses can be largely ex-plained by thermal transfer caused by preheating. Nevertheless, we advise against the use of a low temperature preheat (<200°C) with IR50 to date loess samples because, as has been reported before, the signal appears to be thermally unstable. In general, we conclude that it may not be advisable to apply post-IR IRSL dating to Chinese loess samples where residuals of up to ∼20 Gy are a significant fraction of the total dose. However, these residuals quickly become unimportant when dating older samples, and this is the age range in which post-IR IRSL dating is likely to be most useful. © 2011 Silesian University of Technology, Gliwice, Poland. All rights reserved.
- ItemPost-IR IRSL dating of K-feldspar from last interglacial marine terrace deposits on the Kamikita coastal plain, northeastern Japan(Warsaw : De Gruyter, 2017) Ito, Kazumi; Tamura, Toru; Tsukamoto, SumikoTo establish a suitable luminescence dating protocol for marine terrace deposits in Japan, we tested the applicability of K-feldspar post-infrared (IR) infrared stimulated luminescence (IRSL) (pIRIR) dating using a marine isotope stage (MIS) 5e terrace deposit from the Kamikita coastal plain (NE Japan), where independent age control from a tephra is available. One of the most commonly used pIRIR signals, measured at 290°C with the first IR stimulation temperature at 50°C (pIRIR50/290), faded with a mean g2days value of 1.94 ± 0.19%/decade. In contrast, the pIRIR signal with a higher first IR stimulation temperature of 200°C (pIRIR200/290) had a much lower fading rate (g2days = 0.16 ± 0.49%/decade). The average fading-uncorrected and -corrected pIRIR200/290 ages of MIS 5e subtidal sediments obtained from two sampling sites were 126 ± 3 ka and 132 ± 2 ka, which is in good agreement with the independent age control. We conclude that is it is now possible to use pIRIR protocol to estimate the ages of not only marine terraces formed during MIS 5 substages (5a, 5c) but also of older marine terraces, for which age evidence is limited.
- ItemOn the applicability of post-IR IRSL dating to Japanese loess(Warsaw : De Gruyter, 2011) Thiel, Christine; Buylaert, Jan-Pieter; Murray, Andrew; Tsukamoto, SumikoRecent work on infrared stimulated luminescence (IRSL) dating has focussed on finding and testing signals which show less or negligible fading. IRSL signals measured at elevated temperature following IR stimulation at 50°C (post-IR IRSL) have been shown to be much more stable than the low temperature IRSL signal and seem to have considerable potential for dating. For Early Pleistocene samples of both European and Chinese loess natural post-IR IRSL signals lying in the saturation region of the laboratory dose response curve have been observed; this suggests that there is no significant fading in nature. As a contribution to the further testing of post-IR IRSL dating, we have used 18 samples from two Japanese loess profiles for which quartz OSL and tephra ages up to 600 ka provide age control. After a preheat of 320°C (60 s), the polymineral fine grains (4–11 μm) were bleached with IR at 50°C (200 s) and the IRSL was subsequently measured at 290°C for 200 s. In general, the fading uncorrected post-IR IRSL ages agree with both the quartz OSL and the tephra ages. We conclude that the post-IR IRSL signal from these samples does not fade significantly and allows precise and accurate age determinations on these sediments.
- ItemQuartz OSL and K-feldspar post-IR IRSL dating of sand accumulation in the Lower Liao Plain (Liaoning, NE China)(Warsaw : De Gruyter, 2017) Li, Yan; Tsukamoto, Sumiko; Hu, Ke; Frechen, ManfredThe timing of the formation of extensively distributed sand dunes in the Bohai coastal area and its forcing factors are poorly understood. In this study, the chronology of a well-preserved sand dune located in Panjin Forest Park (PJ) in the Lower Liao Plain (LLP) is investigated using quartz optically stimulated luminescence (OSL) and K-feldspar postinfrared (IR) infrared stimulated luminescence (IRSL) (pIRIR) dating. For the pIRIR measurements, the combination of preheating at 180°C and pIRIR stimulation at 150°C (pIRIR150) is exploited. The quartz results show that the sand dune accumulated from c. 120 a (1890 AD) to c. 70 a (1940 AD) before present, and the underlying sandy soil sediments deposited from c. 5.0 ka to c. 0.13 ka as marsh sediment after the sea level highstand since the mid-Holocene. From the evidence in historical coastline records, the PJ sand dune is an inland sand dune and not a coastal sand dune. Based on further information of climate and temperature change after the Little Ice Age (LIA) and human activity in northeastern China, we conclude that the PJ sand dune accumulation was very likely impacted by the immigrants and land reclamation at the end of Qing dynasty. The fading corrected IR50 ages, the apparent and fading corrected pIRIR150 ages are consistent with quartz ages for two sandy soil samples but overestimate those for six sand samples. The overestimation of the feldspar ages is derived from the residual signal which has not been bleached before burial. The offset obtained from the difference between the quartz OSL and the feldspar pIRIR150 ages are ~20-160 a (predicted residual dose: ~0.08-0.60 Gy), whereas the measured residual dose after bleaching 4 h in a solar simulator yielded age overestimation of ~10-40 a (~0.05-0.16 Gy). The age discrepancy calculated from the predicted residual was larger than those obtained from the laboratory measured residuals. We conclude that the pIRIR150 of aeolian sediment is applicable for samples older than ~1000 years where the effect of the residual dose become negligible. © 2016 Y. Li et al.
- ItemLuminescence Dating of Fluvial Deposits from the Weser Valley, Germany(Warsaw : De Gruyter, 2015) Roskosch, Julia; Tsukamoto, Sumiko; Frechen, ManfredLuminescence dating was applied on coarse-grained monomineralic potassium-rich feld-spar and polymineralic fine-grained minerals of five samples derived from fluvial deposits of the Riv-er Weser in northwestern Germany. We used a pulsed infrared stimulated luminescence (IRSL) single aliquot regenerative (SAR) dose protocol with an IR stimulation at 50°C for 400 s (50 μs on-time and 200 μs off-time). In order to obtain a stable luminescence signal, only off-time IRSL signal was rec-orded. Performance tests gave solid results. Anomalous fading was intended to be reduced by using the pulsed IRSL signal measured at 50°C (IR50), but fading correction was in most cases necessary due to moderate fading rates. Fading uncorrected and corrected pulsed IR50 ages revealed two major fluvial aggradation phases during the Late Pleistocene, namely during marine isotope stage (MIS) 5d (100 ± 5 ka) and from late MIS 5b to MIS 4 (77 ± 6 ka to 68 ± 5 ka). The obtained luminescence ages are consistent with previous 230Th/U dating results from underlying interglacial deposits of the same pit, which are correlated with MIS 7c to early MIS 6.
- ItemChronology of Cauvery Delta Sediments from Shallow Subsurface Cores Using Elevated-Temperature Post-IR IRSL Dating of Feldspar(Warsaw : De Gruyter, 2010) Alappat, L.; Tsukamoto, S.; Singh, P.; Srikanth, D.; Ramesh, R.; Frechen, M.We present the results of luminescence dating of sediments from two cores from the Cauvery Delta in south-east India. Since all natural quartz OSL signals except one sample were in saturation, the elevated temperature post-IR IRSL protocol for K-feldspar was applied to establish a chronology. Internal dose rates of K-feldspar grains were calculated from the measured internal content of potassium, uranium, thorium and rubidium in the bulk of K-feldspar grains using solution ICP-OES and ICP-MS analysis. A substantial scatter in single-aliquot De values was observed which is most probably due to the effect of incomplete bleaching of fluvial sediments before burial. A minimum age model was applied to extract possible depositional ages. The study revealed that except an upper layer of Holocene sediments (< 5m), the majority of the upper ~50m of Cauvery delta sediments were deposited between marine isotope stage MIS-5 and MIS-10 or older. The feldspar luminescence ages also indicate the existence of a period of non deposition or erosion in the upper part of the cores. © 2010 GADAM Centre Institute of Physics, Silesian University of Technology. All rights reserved.
- ItemGeoarchaeological studies on Roman time harbour sediments in Cologne — comparison of different OSL dating techniques(Warsaw : De Gruyter, 2011) Lauer, Tobias; Bonn, Rainer; Frechen, Manfred; Fuchs, Magret; Trier, Marcus; Tsukamoto, SumikoDue to the construction of a new North-South subway in Cologne, Roman time harbour sediments were exposed and were sampled for luminescence dating. A very good independent age control was given by the precise knowledge of the chronology of Roman activity and by radiocarbon ages of charcoal samples. Hence, different methodological approaches within luminescence dating were applied for Holocene heterogeneously bleached fluvial samples and were compared to the known ages. For one sample, optically stimulated luminescence (OSL) dating was applied to coarse-grained quartz using a single aliquot regenerative-dose (SAR) protocol. After De-measurements, dif-ferent statistical approaches were tested (i.e. arithmetic mean, median, minimum age model, finite mixture model, leading edge method and the Fuchs and Lang approach). It is demonstrated that the Fuchs and Lang approach along with the leading edge method yielded the best matching OSL ages with respect to the known ages. For the other sample which showed feldspar contamination within the quartz signal, the post-IR blue stimulated luminescence (double SAR protocol) was measured in three different ways to calculate the De-value: with continuous wave (CW) stimulation with an IR-bleach at 50°C and at 225°C for 100 s prior to the OSL, and pulsed OSL (POSL). It was demonstrated that the IR-stimulation at 225°C has very good potential to remove the feldspar signal contribution as well as pulsed OSL, but the former might deplete parts of the quartz OSL signal. © 2011 Silesian University of Technology, Gliwice, Poland. All rights reserved.