Quartz OSL dating of late Holocene beach ridges from the Magdalen Islands (Quebec,Canada) |
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| Institution: | 1. Institut des sciences de la mer de Rimouski (ISMER), Canada Research Chair in Marine Geology & GEOTOP, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski QC G5L 3A1, Canada;2. Nordic Laboratory for Luminescence Dating, Department of Geoscience, Aarhus University, Risø Campus, DK-4000 Roskilde, Denmark;3. Centre for Nuclear Technologies, Technical University of Denmark, Risø Campus, DK-4000 Roskilde, Denmark;4. Département de biologie, chimie et géographie, Research Chair in Coastal Geoscience & Centre d’études nordiques, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski QC G5L 3A1, Canada;1. Ministry of Education Key Laboratory of Surficial Geochemistry, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China;2. Department of Geography, University of Wisconsin Madison, 160 Science Hall, 550 N. Park St., Madison, WI 53706, USA;3. School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China;1. MOE Laboratory for Earth Surface Processes, Department of Geography, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China;2. Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China;1. Nordic Laboratory for Luminescence Dating, Department of Geosciences, University of Aarhus, Risø Campus, Denmark;2. Center for Nuclear Technologies, Technical University of Denmark, Risø Campus, Denmark;3. Leibniz Institute for Applied Geophysics, S3: Geochronology and Isotope Hydrology, Hannover, Germany;4. School of Geographical and Oceanographical Sciences, Nanjing University, China;5. Department of Earth Sciences, Uppsala University, Sweden;6. Geography, Earth and Environmental Sciences, University of Derby, UK;1. Department of Geography and the Environment, University of the Fraser Valley, Abbotsford, BC, Canada;2. Department of Geography, University of Victoria, Victoria, BC, Canada;3. Hakai Institute, Calvert Island, BC, Canada;1. Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China;2. The Department of Earth Sciences, The University of Hong Kong, Hong Kong, China;3. Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Australia;4. CAEP, MOE Key Laboratory of Western China''s Environmental Systems, Lanzhou University, Lanzhou, China;1. Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8567, Japan;2. Japan Society for the Promotion of Science, Japan |
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| Abstract: | Quartz optically stimulated luminescence (OSL) dating has been applied to sandy beach ridge systems from the Magdalen Islands in the center of the Gulf of St. Lawrence (Quebec, Canada) to provide the first chronological framework for these features. Nineteen beach ridges (22 samples) from four different sites throughout the archipelago were investigated. At one of the sites, samples were taken at 9 m and 7.5 m depth using a vibracore. The quartz is dominated by the fast OSL component and a single-aliquot regenerative-dose (SAR) protocol was used to measure the equivalent doses; a low preheat (180°C/10 s) was chosen to avoid the influence of thermal transfer. The average dose recovery ratio of all samples is 1.02 ± 0.02 (n = 130) suggesting that the SAR protocol works satisfactorily on this material. The OSL ages are internally consistent and supported by independent age control (radiocarbon). The OSL ages indicate that the ridges were built between 2.6 ± 0.2 ka and 0.40 ± 0.10 ka, i.e. during a period of sea level rise. This rise eroded adjacent sandstone cliffs, which contributed a significant sediment supply to the littoral drift and beaches. Some low-lying coasts in the archipelago are still prograding, despite a relative sea level increase of ～1.6 mm/a over the last 600 years. The late Holocene ages obtained in this study indicate that these processes have been active for at least the past two thousand years. This study demonstrates for the first time that OSL dating using quartz has great potential in this area, and is an appropriate method for establishing precise chronologies for coastal sediments in this region of the Gulf of St. Lawrence. |
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| Keywords: | Quartz OSL dating Beach ridges Sea level rise Late Holocene Magdalen Islands |
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