Understanding of the origins of IRSL signals of feldspars for dating sediments in challenging contexts
Abstract
Infrared stimulated luminescence (IRSL) dating measurements of K-feldspar are providing highly valuable age control for sediment deposition, particularly in high energy fluvial contexts. These are especially useful in tectonically active areas where quartz characteristics often limit the applicability of optically stimulated luminescence (OSL) dating. Single grain IRSL is being routinely used to date sediments, although there is great potential also to study grain mobility within soils and weathering profiles, assess patterns and rates of hillslope erosion, determine cooling and exhumation rates by low temperature IRSL thermochronology, and provide input for a range of numerical models of complex interactions between different landscape components. However, in some locations, feldspar luminescence characteristics are significantly poorer than in others. Even where some grains have good characteristics, including intense IRSL emissions, rapid IRSL decay and regular growth as a function of radiations dose, other grains display less encouraging properties. In order to better understand the geologic, geochemical and physical controls on feldspar luminescence behavior, we have explored possible connections to mineralogy, geochemistry, and the geologic origins and evolution of parent lithologies. We have analyzed several samples where subsets of feldspar grains provide disparate dating results in an attempt to determine which characteristics cause variation in the observed apparent age.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMEP44B..07D
- Keywords:
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- 1194 GEOCHRONOLOGY Instruments and techniques;
- 1105 GEOCHRONOLOGY Quaternary geochronology;
- 8194 TECTONOPHYSICS Instruments and techniques;
- 9805 GENERAL OR MISCELLANEOUS Instruments useful in three or more fields