2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 23-8
Presentation Time: 10:05 AM

OPTICAL DATING: A LUMINOUS PAST AND A VERY BRIGHT FUTURE


MAHAN, Shannon A., U.S. Geological Survey, Denver Federal Center, Denver, CO 80225 and LEPPER, Kenneth, Department of Geosciences, North Dakota State University, P.O. Box 6050, Dept. 2745, Fargo, ND 58108-6050, smahan@usgs.gov

With the advent of optically stimulated luminescence (OSL) dating in 1985, there has been, almost literally, an explosion in the application of OSL during the last 30 years allowing the refined establishment of timing and rates of Quaternary geologic events and processes. However, many researchers using the method, or considering it, are not aware of the heritage of modern OSL dating (stretching over half a century) or of the numerous combinations and derivative techniques based on OSL that are now being explored. The latest advances will be placed in a historical context that will allow both seasoned professionals and students to evaluate the techniques and their utility for future projects.

Most development of luminescence technique and application has focused on geological (unheated) sediments. Since the year 2000, there has been the introduction of several additional variants of TL and OSL dating procedures giving rise to new hybrids of the OSL dating “family” including thermal-transfer OSL, post infrared stimulated luminescence, near infra-red radio-fluorescence, and developments in violet light stimulated luminescence to sample deep traps in quartz. Each hybrid is suited to differing geological deposits, processes, and age ranges. Examples will be presented of basic concepts and applications to sediment or rock dating spanning the age range from <1 ka to ~900 ka using innovative instrumentation and new methodological procedures.