Combining Optically Stimulated Luminescence dating and numerical modeling
to constrain the evolution of Miage debris-covered glacier (Mont-Blanc, Italy)
from Little Ice Age to present
Julien Brondex
Glaciology Research Group
Università degli studi di Milano
Promising results there in the bottom right corner! I’m curious about how you extract the samples from the ice without exposing them – do you then sample the non-spray-painted side? Can the samples be bleached through the ice when the ice is thin?
It looks like Miage offers you quite a complex ice flow modelling site as well and I was wondering if you are also trying the technique at a glacier with simpler glacier geometry?
Good luck!
Hi Lindsey,
Thanks for your questions. Yes the two luminescence-depth profiles that I put on the poster are the most promising ones. I have several others but most of them do not look as good as these two.
Regarding the sampling, it was a bit tricky indeed. We tried to spot debris embedded in ice cliff. Because the interesting information (burial time of debris) relates to the amount of vertical shift of the lower plateau on the luminescence-depth profile rather than to the depth of the bleaching front (on the contrary to rock surface exposure dating), it should not be so much of a problem to have them exposed during sampling. Nevertheless, we tried to be as fast as possible in retrieving them from the ice and putting them into lightproof bags.
It’s true that Miage is probably not the easiest glacier to model. Especially because ice thickness is highly uncertain (when we compare the three published ice thickness estimates, they show differences higher than 100% on large part of the glacier) and modeled ice velocity field is very sensitive to implemented ice thickness. That’s why it would be great if we could do some GPR measurements in the field later this spring.