کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1888862 | 1043744 | 2007 | 10 صفحه PDF | دانلود رایگان |
The effect of the presence of feldspars that can be shown to exhibit anomalous fading is investigated using the double-SAR protocol. This protocol has been suggested as a method of isolating an optically stimulated luminescence (OSL) signal dominated by quartz from a polymineralic mixture of grains. The progressive removal of feldspars from the silt-sized fraction of sediments from Bignell Hill, Nebraska, is also investigated using chemical treatment with hydrofluorosilicic acid for different durations; the appropriate treatment duration for these sediments is identified as being 7 days. For untreated material, the double-SAR protocol yields IRSL and [post-IR] OSL signals that are both dominated by feldspars and that give the same value for the equivalent dose (De)(De) determination. However, for material treated with hydrofluorosilicic acid for 7 days, the IRSL and [post-IR] OSL signals have distinctly different characteristics and appear to be dominated by feldspar and by quartz, respectively. Furthermore, the DeDe values determined for the feldspar-dominated IRSL signal are about half those obtained for the quartz-dominated [post-IR] OSL signal. This demonstrates that the double-SAR protocol is not always capable of isolating a quartz-dominated signal; clearly, in some circumstances it is necessary to apply a chemical pre-treatment to remove the contribution from feldspars prior to any luminescence measurements being made.
Journal: Radiation Measurements - Volume 42, Issue 10, November 2007, Pages 1627–1636