Abstract Details
(2020) Activation Energy of Annealed, Fully Metamict Samarskite Determined with 57Fe Mössbauer Spectroscopy
Malczewski D & Dziurowicz M
https://doi.org/10.46427/gold2020.1710
06d: Room 2, Thursday 25th June 05:39 - 05:42
Dariusz Malczewski
View abstracts at 3 conferences in series
Maria Dziurowicz View abstracts at 3 conferences in series
Maria Dziurowicz View abstracts at 3 conferences in series
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Submitted by Charles Magee on Thursday 25th June 04:10
Do you envisage the radiation-induced iron valence change is spatially associated with the U or Th source, or is it more broadly distributed? Is this resolvable in your analyses?
Thank you for your question and sorry for the delay but I have just noticed it. Regarding the question, I think the distribution of U and/or Th alone should not affect changes in the valence state of Fe, but the radiation damage arising from the decays of U and Th, yes. Areas with radiation damage are more penetrated by atmospheric hydrogen resulting in the formation of coordinating OH- groups instead of O2- as in crystalline phase of a mineral.. To maintain the charge balance, iron in such an environment is reduced from 3+ to 2+. That is why in many metamict minerals a large contribution of iron 2+ is observed despite the fact that in the crystalline state of this mineral iron 2+ does not occur (e.g. davidite). Generally, decays from the 232-Th series cause greater radiation damage than decays from the 238-U series. This effect can be observed using Mossbauer spectroscopy (in combination with X-ray diffraction). Regards Darek :)
Do you envisage the radiation-induced iron valence change is spatially associated with the U or Th source, or is it more broadly distributed? Is this resolvable in your analyses?
Thank you for your question and sorry for the delay but I have just noticed it. Regarding the question, I think the distribution of U and/or Th alone should not affect changes in the valence state of Fe, but the radiation damage arising from the decays of U and Th, yes. Areas with radiation damage are more penetrated by atmospheric hydrogen resulting in the formation of coordinating OH- groups instead of O2- as in crystalline phase of a mineral.. To maintain the charge balance, iron in such an environment is reduced from 3+ to 2+. That is why in many metamict minerals a large contribution of iron 2+ is observed despite the fact that in the crystalline state of this mineral iron 2+ does not occur (e.g. davidite). Generally, decays from the 232-Th series cause greater radiation damage than decays from the 238-U series. This effect can be observed using Mossbauer spectroscopy (in combination with X-ray diffraction). Regards Darek :)
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