Objectives

1er avril 2015 ( maj : 19 juin 2015 ), par Irene Schimmelpfennig

Investigating the local glacier extents during the past thousands of years is necessary to understand the long-term morphological and environmental evolution of the Mont Blanc Massif.
This part of the project deals with the glacier fluctuations in the Mont Blanc Massif and the related erosional effects of the ice cover during the Holocene (past 11,000 years). Because glacier advances and retreats are driven by the local climate, the results will allow reconstructing key events in the Holocene climate evolution at the Mont Blanc Massif, benefitting from the glacier models calibrated with data from the recent past.
We study the Holocene glacier fluctuations using cosmogenic nuclide dating of moraines and deglaciated bedrock. A particular focus lies on the investigation of the glacier retreat during past warm periods based on an approach that was recently developed by Goehring et al. (2011) and combines measurements of in situ cosmogenic carbon-14 and beryllium-10 in glacially polished bedrock.
Goehring et al. (2011, 2012) have shown that the Rhone Glacier (Switzerland) was shorter than today during half of the Holocene period and its length might momentary have been less than half of the current length. Did the Mont Blanc Massif glaciers undergo a similar evolution ?

Our main objectives consist in :
-  Dating and mapping of Holocene key extents of advanced glaciers
-  Quantification of cumulative period of galcier retractation during the Holocene
-  Modeling of local Holocene glacier-climate dynamics and subglacial abrasion rates

References :
Goehring et al., 2011, The Rhone Glacier was smaller than today for most of the Holocene, Geology, v. 39, p. 679-682.
Goehring et al., 2012, Holocene dynamics of the Rhone Glacier, Switzerland, deduced from ice flow models and cosmogenic nuclides, Earth and Planetary Science Letters, v. 351–352, p. 27–35.

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