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A Single-Aliquot Luminescence Dating Procedure For K-Feldspar Based On The Dose-Dependent Met-Pirir Signal Sensitivity, Bo Li, Richard G. Roberts, Zenobia Jacobs, Sheng-Hua Li
A Single-Aliquot Luminescence Dating Procedure For K-Feldspar Based On The Dose-Dependent Met-Pirir Signal Sensitivity, Bo Li, Richard G. Roberts, Zenobia Jacobs, Sheng-Hua Li
Faculty of Science, Medicine and Health - Papers: part A
It has been shown previously that the ‘sensitivity’ of the post-infrared infrared stimulated luminescence (post-IR IRSL or pIRIR) signal—that is, the intensity of the test dose signal (Tx)—can retain a ‘memory’ of the pre-dose received in nature, but can be reset by sunlight bleaching. Based on this observation, we describe here a single-aliquot regenerative-dose (SAR) multiple elevated temperature (MET) pIRIR dating procedure for K-feldspar that differs in one important respect from the conventional SAR MET-pIRIR procedure. Instead of using a high temperature IR bleaching step between each SAR cycle—as in the conventional procedure—our modified procedure uses a solar simulator bleach …
Extending The Age Limit Of Luminescence Dating Using The Dose-Dependent Sensitivity Of Met-Pirir Signals From K-Feldspar, Bo Li, Zenobia Jacobs, Richard G. Roberts, Sheng-Hua Li
Extending The Age Limit Of Luminescence Dating Using The Dose-Dependent Sensitivity Of Met-Pirir Signals From K-Feldspar, Bo Li, Zenobia Jacobs, Richard G. Roberts, Sheng-Hua Li
Faculty of Science, Medicine and Health - Papers: part A
We investigated the sensitivity change of multiple-elevated-temperature (MET) stimulated post-infrared infrared-stimulated luminescence (MET-pIRIR) signals as a response to irradiation, sunlight bleaching and heating using samples from the Mu Us Desert, central China. A strong dose dependence of MET-pIRIR signal sensitivity was observed. The intensity of the test-dose signals (Tx) increase with the pre-dose received. Furthermore, the signal sensitivity can be reset by sunlight bleaching or heating. This suggests that both the electron traps and hole centres in K-feldspar can be bleached by sunlight, and can, therefore, be used for dating. Using the test-dose signal as a monitor for sensitivity change, …
On The Dose Dependency Of The Bleachable And Non-Bleachable Components Of Irsl From K-Feldspar: Improved Procedures For Luminescence Dating Of Quaternary Sediments, Bo Li, Richard G. Roberts, Zenobia Jacobs
On The Dose Dependency Of The Bleachable And Non-Bleachable Components Of Irsl From K-Feldspar: Improved Procedures For Luminescence Dating Of Quaternary Sediments, Bo Li, Richard G. Roberts, Zenobia Jacobs
Faculty of Science, Medicine and Health - Papers: part A
The infrared (IR) stimulated luminescence (IRSL) and post-IR IRSL (pIRIR) signals from K-feldspar can, for convenience, be divided into two components, bleachable and ‘non-bleachable’, where the latter corresponds to the ‘residual’ signal observed in sunlight-bleached samples. In this paper, we examine the non-bleachable component of IRSL of K-feldspar for several sedimentary samples from across Eurasia. We observed a large variability in the residual doses among these samples after prolonged exposure to sunlight. By employing multiple elevated temperature (MET) IR stimulations at 50–300 °C, we show that the residual dose increases systematically with stimulation temperature, attaining values as high as ∼50 …
The Effect Of Band-Tail States On The Thermal Stability Of The Infrared Stimulated Luminescence From K-Feldspar, Bo Li, Sheng-Hua Li
The Effect Of Band-Tail States On The Thermal Stability Of The Infrared Stimulated Luminescence From K-Feldspar, Bo Li, Sheng-Hua Li
Faculty of Science, Medicine and Health - Papers: part A
The thermal stability of the infrared stimulated luminescence (IRSL) signal from a sedimentary K-feldspar was investigated using isothermal decay study. It is observed that the isothermal decay of IRSL signal cannot be described using a first-order exponential decay function. Instead, the decay can be well described by considering the presence of band-tail states. Based on the isothermal decay results, a trap depth of ∼1.92 eV was obtained for the IRSL stimulated at 50 °C and the width of the band-tail states was found to be ∼0.37 eV below the conduction band edge. Deeper trap depths (up to ∼2.06 eV) were …
Luminescence Dating Of K-Feldspar From Sediments: A Protocol Without Anomalous Fading Correction, Bo Li, Sheng-Hua Li
Luminescence Dating Of K-Feldspar From Sediments: A Protocol Without Anomalous Fading Correction, Bo Li, Sheng-Hua Li
Faculty of Science, Medicine and Health - Papers: part A
A protocol for optical dating of potassium-rich feldspar (K-feldspar) is proposed. It utilizes the infrared stimulated luminescence (IRSL) signal measured by progressively increasing the stimulation temperature from 50 to 250 °C in step of 50 °C, so-called multi-elevated-temperature post-IR IRSL (MET-pIRIR) measurements. Negligible anomalous fading was observed for the MET-pIRIR signals obtained at 200 and 250 °C. This was supported by equivalent dose (De) measurements using the IRSL and MET-pIRIR signals. The De values increase progressively from 50 °C to 200 °C, but similar De values were obtained for the MET-pIRIR signal at 200 and 250 °C. Measurement of modern …
Reply To Comment By Huntley On "Isochron Dating Of Sediments Using Luminescence Of K-Feldspar Grains", Bo Li, Sheng-Hua Li, Hui Zhao
Reply To Comment By Huntley On "Isochron Dating Of Sediments Using Luminescence Of K-Feldspar Grains", Bo Li, Sheng-Hua Li, Hui Zhao
Faculty of Science, Medicine and Health - Papers: part A
In our isochron studies using grains of different sizes, we observed that the IRSL ages obtained from K‐feldspar without correction for fading show an increase with increasing grain size [Li et al., 2007, 2008]. Huntley [2011a] argued that this result was caused by different fading rates for grains of different sizes or by different source materials for different sizes of grains. We replied to his comment [Li et al., 2011], suggesting that the phenomenon could be explained by there being different fading rates for the IRSL signals produced by natural and laboratory irradiation [Li et al., 2007, 2008]. Instead of …
Thermal Stability Of Infrared Stimulated Luminescence Of Sedimentary K-Feldspar, Bo Li, Sheng-Hua Li
Thermal Stability Of Infrared Stimulated Luminescence Of Sedimentary K-Feldspar, Bo Li, Sheng-Hua Li
Faculty of Science, Medicine and Health - Papers: part A
The thermal stability of the infrared stimulated luminescence (IRSL) signal measured at 50 °C as a function of IR stimulation time was investigated using KF grains extracted from sediments from central China. A dependence of thermal stability of IRSL signal on IR stimulation time and stimulation temperature were observed in pulse annealing studies. Relatively lower thermal stability is given by the initial part of the IRSL measured at 50 °C, than the later part of IRSL curve. Based on these observations, the thermal stability of the post-IR IRSL signal stimulated at elevated temperatures (100–200 °C) was also investigated. It was …
Infrared Stimulated Luminescence Measurements Of Single Grains Of K-Rich Feldspar For Isochron Dating, Bo Li, Sheng-Hua Li, Geoffrey A. T Duller, Ann G. Wintle
Infrared Stimulated Luminescence Measurements Of Single Grains Of K-Rich Feldspar For Isochron Dating, Bo Li, Sheng-Hua Li, Geoffrey A. T Duller, Ann G. Wintle
Faculty of Science, Medicine and Health - Papers: part A
This paper explores the use of single grain luminescence measurements in isochron dating of K-rich feldspars. The thermal stability of individual feldspar grains was investigated using pulse annealing methods, which appears to distinguish between K-rich and Na-rich feldspars. A good isochron fit was obtained using synthetic aliquots produced from the single grain data set and the age obtained based on an assumed K content of 13 ± 1% was in good agreement with that obtained using single aliquot measurements (and with other age control).
Anomalous Fading: A Reply To The Comment By Huntley On "Isochron Measurements Of Naturally Irradiated K-Feldspar Grains", Bo Li, Sheng-Hua Li, Ann G. Wintle, Hui Zhao
Anomalous Fading: A Reply To The Comment By Huntley On "Isochron Measurements Of Naturally Irradiated K-Feldspar Grains", Bo Li, Sheng-Hua Li, Ann G. Wintle, Hui Zhao
Faculty of Science, Medicine and Health - Papers: part A
We are pleased that Huntley (this issue) has put forward another explanation for the data that we obtained when we measured the equivalent doses (De) of potassium (K) feldspar grains of different diameters using their infrared stimulated luminescence (IRSL) signals (Li et al., 2007). We also measured the fading rates for the IRSL signals from grains of different size and concluded that the fading rates were independent of grain size. Huntley is concerned that the fading rates (g-values) that we obtained had relatively large errors and that these could have masked any minor differences in the g-values; a small systematic …