Investigation of OSL surface exposure dating to reconstruct post-LIA glacier fluctuations in the French Alps (Mer de Glace, Mont Blanc massif)

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Serval ID
serval:BIB_EEB47AA6ECD6
Type
Article: article from journal or magazin.
Publication sub-type
Case report (case report): feedback on an observation with a short commentary.
Collection
Publications
Institution
Title
Investigation of OSL surface exposure dating to reconstruct post-LIA glacier fluctuations in the French Alps (Mer de Glace, Mont Blanc massif)
Journal
Quaternary Geochronology
Author(s)
Lehmann B., Valla P. G., King G. E., Herman F.
ISSN
1871-1014
ISSN-L
1878-0350
Publication state
Published
Issued date
03/12/2017
Peer-reviewed
Oui
Volume
44
Pages
63-74
Language
english
Abstract
Providing quantitative constraints on late Pleistocene glacier fluctuations remains an important challenge for
understanding glacier response to past and future climate changes. In most mountainous settings, paleo-glacier
reconstructions are limited because they often lack precise temporal constraints. Different geochronological
methods have been developed and applied to date specific geomorphological or sedimentological markers for
paleo-glacier dynamics. Recently, OSL (Optically Stimulated Luminescence) surface exposure dating has been
introduced and provides us with an opportunity to improve paleo-glacier reconstructions. This method is based
on the sensitivity of the OSL signal from rock minerals to light, resulting in bleaching of the OSL signal within the
upper first millimeters of the exposed rock surface, a process that depends on the exposure age, the rock type and
the local setting (e.g. topographic shielding, bedrock orientation etc.). Here, we investigate the potential of OSL
surface exposure along a vertical cross-section of polished bedrock surfaces with known post-LIA (Little Ice Age)
exposure ages (from 3 to 137 years) along the Mer de Glace glacier (Mont Blanc massif, France). The infrared
stimulated luminescence (IRSL) signals from rock slices exhibit increasingly deep bleaching profiles with elevation
and thus exposure age, which is consistent with progressive glacier thinning since the LIA. Our results
show that OSL surface exposure dating can be applied to periglacial environments, and is a promising tool for
high-resolution reconstruction of ice extent fluctuations, both in space and time.
Keywords
Optically stimulated luminescence (OSL) Surface exposure dating Luminescence depth profile Paleo-glacier reconstruction Mont Blanc massif
Create date
24/01/2018 13:29
Last modification date
20/08/2019 16:16
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