Paper No. 2
Presentation Time: 1:45 PM
A REVIEW OF OPTICAL DATING OF COASTAL STRANDPLAINS ACROSS THE UPPER GREAT LAKES
In 2002, optical dating was adopted as the primary method of dating coastal beach ridges as part of the Lake Level and Shoreline History project of the USGS Global Climate Change Program. Ten strandplains that include more than 600 individual beach ridges have been studied, yielding optical ages throughout the upper Great Lakes. The objective of the program is to formulate late Holocene lake-level reconstructions from cross-strandplain chronologies produced using ages from individual beach ridges. Independently, the existing data generated through sampling for optical dating provide a wealth of information related to coastal development and insight in to the applicability of optical dating in nearshore coastal landscapes of the Great Lakes. This contribution reviews the data generated during the process of applying optical dating, specifically single-aliquot regeneration methods, throughout the upper Great Lakes. Specific issues that relate to age generation and accurate dating include discussion of sampling in the field and facies identification, solar resetting, determining water content, reproducibility of results, variability in dose rate, and the low background signal of Great Lakes sediments. The goal of this review is to provide insight in to factors that affect optical age generation within and among sites in an effort to broaden the understanding and application of optical dating in the Great Lakes and to advance ongoing research.