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On the dose dependency of the bleachable and non-bleachable components of IRSL from K-feldspar: improved procedures for luminescence dating of Quaternary sediments

Journal Article


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Abstract


  • 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 Gy at 300 °C, even after several hours to tens of hours of exposure to unfiltered sunlight. We examined two samples in detail and found that the bleachable and non-bleachable components produced different dose response curves. Pulse annealing studies showed that the non-bleachable component is more stable than the bleachable component, suggesting that a preheat procedure cannot eliminate the non-bleachable component. Additional experiments revealed that the non-bleachable component is dose dependent. Owing to this dose dependency, we demonstrate mathematically and empirically that the simple subtraction of a residual dose from the measured equivalent dose (De) – which is the most common approach employed (if any residual dose is subtracted at all) – will result in underestimation of the actual De. We present a method to correct for the dose dependency of the residual dose, which can improve the accuracy of either MET-pIRIR or pIRIR age estimates for samples in which the non-bleachable component represents a significant fraction of the measured signals.

Publication Date


  • 2013

Citation


  • Li, B., Roberts, R. G. & Jacobs, Z. (2013). On the dose dependency of the bleachable and non-bleachable components of IRSL from K-feldspar: improved procedures for luminescence dating of Quaternary sediments. Quaternary Geochronology, 17 1-13.

Scopus Eid


  • 2-s2.0-84878428514

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1897&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/884

Number Of Pages


  • 12

Start Page


  • 1

End Page


  • 13

Volume


  • 17

Abstract


  • 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 Gy at 300 °C, even after several hours to tens of hours of exposure to unfiltered sunlight. We examined two samples in detail and found that the bleachable and non-bleachable components produced different dose response curves. Pulse annealing studies showed that the non-bleachable component is more stable than the bleachable component, suggesting that a preheat procedure cannot eliminate the non-bleachable component. Additional experiments revealed that the non-bleachable component is dose dependent. Owing to this dose dependency, we demonstrate mathematically and empirically that the simple subtraction of a residual dose from the measured equivalent dose (De) – which is the most common approach employed (if any residual dose is subtracted at all) – will result in underestimation of the actual De. We present a method to correct for the dose dependency of the residual dose, which can improve the accuracy of either MET-pIRIR or pIRIR age estimates for samples in which the non-bleachable component represents a significant fraction of the measured signals.

Publication Date


  • 2013

Citation


  • Li, B., Roberts, R. G. & Jacobs, Z. (2013). On the dose dependency of the bleachable and non-bleachable components of IRSL from K-feldspar: improved procedures for luminescence dating of Quaternary sediments. Quaternary Geochronology, 17 1-13.

Scopus Eid


  • 2-s2.0-84878428514

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1897&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/884

Number Of Pages


  • 12

Start Page


  • 1

End Page


  • 13

Volume


  • 17