FELDSPAR LUMINESCENCE CHRONOLOGY AND THE MIDDLE TO LATE PLEISTOCENE HISTORY OF THE NE SECTOR OF THE LAURENTIDE ICE SHEET

Over the last three decades, luminescence dating has been applied to interglacial and interstadial sediments found above and beneath till emplaced by the waxing and waning Laurentide Ice Sheet or by regional ice masses originating from the Appalachians. Most of the dating projects focused on alluvial and/or lacustrine sediments, but some significant chronologies have also emerged from applications to glaciolacustrine bodies.

The earliest developments were based on fine-grains thermoluminescence, a process that was prone to age overestimates as this luminescence signal is known to carry a relatively large hard-to-bleach component. Since the advent of optical dating in 1985, luminescence dating has progressed rapidly and several sedimentary contexts from the area of interest have been tested. Even though some quartz OSL dates have been reported, most of the efforts have focused on the use of feldspar infrared stimulated luminescence. Methods have been developed to extract the luminescence component generated over the depositional time period and, in the case of feldspar, to correct for its instability known as anomalous fading.

The objective of this paper is to propose a review of the regional IRSL dating results, already published or in progress. At this stage, the available luminescence chronologies cover several of the ice-free episodes that had prevailed in and around the St. Lawrence, Hudson and Connecticut River drainage basins over the last 250 000 years. The IRSL dates will be evaluated and discussed in the context of a more general synchronization between glaciated NA and the sea level history recorded by the Late Quaternary sequences of the Atlantic coastal plain.