LOESSFEST'09 | Aug. 31st – Sept. 3rd, 2009 |Novi Sad-Serbia
The Importance of Chronology in the Study of Loess: Developments in Luminescence Dating, and Future Challenges
Roberts, H. M.1
1Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Ceredigion, Wales, SY23 3DB
Intercalated deposits of loess and palaeosols are spread over vast geographic
areas, and preserve important records of past climate change. Some key sites have
been studied intensively over the years, revealing detailed fluctuations in various
palaeoclimatic indicators. However, if these detailed site-specific studies are to
be linked together in order to investigate the timing, nature, and extent of such
palaeoclimatic fluctuations, it is essential to establish a reliable numerical chronology.
Recent exciting developments in luminescence dating have revolutionised
the dating technique, through significant improvements in both the precision
and accuracy of optically stimulated luminescence (OSL) ages, and also as a
result of the establishment and testing of new rigorous quality control checks for
the OSL signals examined. The development of luminescence dating is inextricably
linked to the study of loess deposits. Loess deposits have been an important
testing ground for these newly developing luminescence dating techniques, and
they continue to play a significant role today in developing the next generation of
luminescence techniques.
The evolution of luminescence dating from the earliest days until the recent
important technological advances will be outlined, and the current methods
of choice will be explained. Having made significant advances in the dating
of quartz, which is now almost considered routine in some geomorphological settings,
attention has recently turned to new challenges. Current research is principally
focussing on two key areas: 1) improving the reliability of dating using feldspars,
which cover a longer dating range than quartz, but which still pose some
potentially serious challenges for luminescence dating, and 2) using new luminescence
signals to significantly extend the maximum age range achievable (e.g. by
an order of magnitude). These more recent developments will be discussed, and
likely future challenges will be considered.