Abstract Details
(2020) Mechanisms of Ductile Deformation in the Lithospheric Mantle (Keynote 3f)
Demouchy S & Cordier P
https://doi.org/10.46427/gold2020.547
The author has not provided any additional details.
03g: Room 1, Thursday 25th June 08:00 - 08:03
Sylvie Demouchy
View all 3 abstracts at Goldschmidt2020
Patrick Cordier View abstracts at 7 conferences in series
Patrick Cordier View abstracts at 7 conferences in series
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Submitted by Sarah Lambart on Thursday 25th June 04:35
Hi Sylvie, I'm glad you accepted our invitation as keynote speaker and I'm very sorry to miss your Q&A (early remote-teaching meeting tomorrow...). It is truly amazing that we can witness grain boundary mobility! As you showed, grain size seems to have major implications on the governing process of the mantle rheology, and as you illustrated at the end of your talk, natural samples show very contrasted grain size. I was wondering if people, including your group, have been trying to do experiments with heterogeneous grain size distribution in a given sample, and if not, do you have an idea of what you could expect to learn with these experiments?
Hi Sylvie, I'm glad you accepted our invitation as keynote speaker and I'm very sorry to miss your Q&A (early remote-teaching meeting tomorrow...). It is truly amazing that we can witness grain boundary mobility! As you showed, grain size seems to have major implications on the governing process of the mantle rheology, and as you illustrated at the end of your talk, natural samples show very contrasted grain size. I was wondering if people, including your group, have been trying to do experiments with heterogeneous grain size distribution in a given sample, and if not, do you have an idea of what you could expect to learn with these experiments?
Submitted by sylvie demouchy on Thursday 25th June 07:25
Thank you Sarah for the question. no, we did not perform experiment with a controlled heterogeneous grain size (like perfectly controlled bimodal distribution), but most of the old experiments already have a sluggish bimodal distribution. Nevertheless, we would expect that, at high temperature (>1200 °C) , ionic diffusion and the small grains will accommodate de deformation more easily than the large grains, but the number of active mechanisms can become important. e.g., grain growth ( or GB migration) will kick in too, and with increasing grain size, stress will rise. such experiment are challenging but also very exiting.
Thank you Sarah for the question. no, we did not perform experiment with a controlled heterogeneous grain size (like perfectly controlled bimodal distribution), but most of the old experiments already have a sluggish bimodal distribution. Nevertheless, we would expect that, at high temperature (>1200 °C) , ionic diffusion and the small grains will accommodate de deformation more easily than the large grains, but the number of active mechanisms can become important. e.g., grain growth ( or GB migration) will kick in too, and with increasing grain size, stress will rise. such experiment are challenging but also very exiting.
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