PRECISION AND ACCURACY IN THE OPTICALLY STIMULATED LUMINESCENCE DATING OF SEDIMENTARY QUARTZ: A STATUS REVIEW
PRECISION AND ACCURACY IN THE OPTICALLY STIMULATED LUMINESCENCE DATING OF SEDIMENTARY QUARTZ: A STATUS REVIEW
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作者：
A. Murray;J. Olley
光释光（OSL）测年法在晚第四纪研究中越来越多地被用来建立沉积物沉积年代学。在过去几年中，在仪器、优选矿物和各种测量原型方面有了相当大的技术发展。后者的新方法，特别是随着单等分再生剂量（SAR）协议的引入，基于石英OSL信号的文献中的年龄越来越多。本文通过回顾已发表和未发表的SAR石英年龄来检验这些结果的可靠性，其中存在一些独立的年龄控制。它首先讨论了现代（零年龄）沉积物的研究，以及这些结果对不完全漂白的重要性的影响，特别是在水岸沉积物中，即初始光照射预计不足以将沉积时的表观剂量降低到最终掩埋剂量的可忽略部分的沉积物。然后比较了OSL与风成、河流/湖泊、海相和冰川-河流/湖泊等不同沉积类型的独立年龄。它的结论是，在一般情况下，年龄是准确的，在没有证据表明系统误差的年龄范围从上个世纪至少350 ka。尽管如此，公布的一小部分OSL年龄的不确定性可能被低估了。我们得出结论，石英光释光测年是一个可靠的年代学工具，这一结论反映在其日益普及的第四纪研究。
Optically stimulated luminescence (OSL) dating of light-exposed sediments is used increasingly as a mean of establishing a sediment deposition chronology in a wide variety of late Quaternary studies. There has been considerable technological development in the last few years n in instrumentation, in the preferred mineral, and in various measurement proto- cols. New approaches to the latter, especially with the introduction of the single-aliquot regenerative-dose (SAR) protocol, have given rise to an increasing number of ages in the li- terature based on the OSL signals from quartz. This paper examines the reliability of these results by reviewing both published and unpublished SAR quartz ages for which some independent age control exists. It first discusses studies of modern (zero age) sediments, and the implications of these results for the importance of incomplete bleaching, especially in water-lain sediments, i.e. sediments for which the initial light exposure is expected to have been insufficient to reduce the apparent dose at deposition to a negligible fraction of the final burial dose. It then compares OSL and independent ages derived from various types of sedi- ments, including aeolian, fluvial/lacustrine, marine and glacio-fluvial/lacustrine. It is concluded that, in general, the ages are accurate, in that there is no evidence for systematic errors over an age range from the last century to at least 350 ka. Nevertheless, the published uncertain- ties of a small fraction of OSL ages are probably underestimated. We conclude that OSL dating of quartz is a reliable chronological tool; this conclusion is reflected in its growing popularity in Quaternary studies.