Residual Osl Signals from Modern Greenlandic River Sediments

• Published in: GEOCHR
• Main Author: Alexanderson, Helena
• Format: Article in Journal/Newspaper
• Language: English
• Published: Walter de Gruyter GmbH 2007
• Subjects: Earth and Planetary Sciences (miscellaneous); Greenland; Jameson Land; East Greenland; greenlandic
• Online Access: http://dx.doi.org/10.2478/v10003-007-0001-6; http://content.sciendo.com/view/journals/geochr/26/-1/article-p1.xml; https://www.sciendo.com/pdf/10.2478/v10003-007-0001-6

Residual Osl Signals from Modern Greenlandic River Sediments Ripple-laminated sandy deposits at shallow water depths in four rivers on Jameson Land, East Greenland were sampled for optically stimulated luminescence (OSL) dating. Silt-sized grains have significantly higher equivalent doses (~1.1 Gy) than sand grains (~0.1 Gy). This suggests that coarse grain-size fractions are better bleached and more suitable than fine grains for OSL dating of glaciofluvial/fluvial sediments. A sample from a sidebar deposited during the spring flood yielded 1.0 Gy (~500 years) while a subaerial deposit was completely zeroed. The spring flood deposit is considered to be most similar to deglacial conditions and incomplete bleaching of this amount (1 Gy) is generally not a significant source of error for sediments of Pleistocene age. Most samples have rather poor luminescence characteristics and are affected by thermal transfer if preheat temperatures at or above 260°C are used.