Constraints on oxygen fugacity within metal capsules
Experiments were conducted with olivine encapsulated or wrapped in five different metals (Pt, Ni, Ni[subscript 70]Fe[subscript 30], Fe, and Re) to determine the oxygen fugacity in the interior of large capsules used for deformation and seismic property experiments. Temperature (1200°C ), pressure (3...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Springer Berlin Heidelberg
2018
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| Online Access: | http://hdl.handle.net/1721.1/116932 https://orcid.org/0000-0001-5036-4572 |
| _version_ | 1811070240082100224 |
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| author | Berry, Andrew Jackson, Ian Garapić, Gordana Cline II, Christopher J. Faul, Ulrich |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Berry, Andrew Jackson, Ian Garapić, Gordana Cline II, Christopher J. Faul, Ulrich |
| author_sort | Berry, Andrew |
| collection | MIT |
| description | Experiments were conducted with olivine encapsulated or wrapped in five different metals (Pt, Ni, Ni[subscript 70]Fe[subscript 30], Fe, and Re) to determine the oxygen fugacity in the interior of large capsules used for deformation and seismic property experiments. Temperature (1200°C ), pressure (300 MPa), and duration (24 h) were chosen to represent the most common conditions in these experiments. The oxygen fugacity was determined by analysing the Fe content of initially pure Pt particles that were mixed with the olivine powder prior to the experiments. Oxygen fugacities in the more oxidizing metal containers are substantially below their respective metal-oxide buffers, with the fO[subscript 2] of sol–gel olivine in Ni about 2.5 orders of magnitude below Ni–NiO. Analysis of olivine and metal blebs reveals three different length-, and hence diffusive time scales: (1) Fe loss to the capsule over ∼ 100 μm, (2) fO[subscript 2] gradients at the sample–capsule interface up to 2 mm into the sample, and (3) constant interior fO[subscript 2] values with an ordering corresponding to the capsule material. The inferred diffusive processes are: Fe diffusion in olivine with a diffusivity ∼10[superscript −14]m[superscript 2]/s, diffusion possibly of oxygen along grain boundaries with a diffusivity ∼10[superscript −12]m[superscript 2]/s , and diffusion possibly involving pre-existing defects with a diffusivity ∼10[superscript −10]m[superscript 2]/s. The latter, fast adjustment to changing fO[subscript 2] may consist of a rearrangement of pre-existing defects, representing a metastable equilibrium, analogous to decoration of pre-existing defects by hydrogen. Full adjustment to the external fO[subscript 2] requires atomic diffusion. Keywords: Oxygen fugacity, Olivine defects, Diffusion, Upper mantle |
| first_indexed | 2024-09-23T08:33:20Z |
| format | Article |
| id | mit-1721.1/116932 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:33:20Z |
| publishDate | 2018 |
| publisher | Springer Berlin Heidelberg |
| record_format | dspace |
| spelling | mit-1721.1/1169322024-05-15T03:30:18Z Constraints on oxygen fugacity within metal capsules Berry, Andrew Jackson, Ian Garapić, Gordana Cline II, Christopher J. Faul, Ulrich Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Faul, Hans Ulrich Experiments were conducted with olivine encapsulated or wrapped in five different metals (Pt, Ni, Ni[subscript 70]Fe[subscript 30], Fe, and Re) to determine the oxygen fugacity in the interior of large capsules used for deformation and seismic property experiments. Temperature (1200°C ), pressure (300 MPa), and duration (24 h) were chosen to represent the most common conditions in these experiments. The oxygen fugacity was determined by analysing the Fe content of initially pure Pt particles that were mixed with the olivine powder prior to the experiments. Oxygen fugacities in the more oxidizing metal containers are substantially below their respective metal-oxide buffers, with the fO[subscript 2] of sol–gel olivine in Ni about 2.5 orders of magnitude below Ni–NiO. Analysis of olivine and metal blebs reveals three different length-, and hence diffusive time scales: (1) Fe loss to the capsule over ∼ 100 μm, (2) fO[subscript 2] gradients at the sample–capsule interface up to 2 mm into the sample, and (3) constant interior fO[subscript 2] values with an ordering corresponding to the capsule material. The inferred diffusive processes are: Fe diffusion in olivine with a diffusivity ∼10[superscript −14]m[superscript 2]/s, diffusion possibly of oxygen along grain boundaries with a diffusivity ∼10[superscript −12]m[superscript 2]/s , and diffusion possibly involving pre-existing defects with a diffusivity ∼10[superscript −10]m[superscript 2]/s. The latter, fast adjustment to changing fO[subscript 2] may consist of a rearrangement of pre-existing defects, representing a metastable equilibrium, analogous to decoration of pre-existing defects by hydrogen. Full adjustment to the external fO[subscript 2] requires atomic diffusion. Keywords: Oxygen fugacity, Olivine defects, Diffusion, Upper mantle National Science Foundation (U.S.) (Grant EAR 1321889) 2018-07-12T15:03:36Z 2018-10-07T05:00:05Z 2017-12 2018-06-05T04:24:12Z Article http://purl.org/eprint/type/JournalArticle 0342-1791 1432-2021 http://hdl.handle.net/1721.1/116932 Faul, Ulrich H., et al. “Constraints on Oxygen Fugacity within Metal Capsules.” Physics and Chemistry of Minerals, vol. 45, no. 6, June 2018, pp. 497–509. https://orcid.org/0000-0001-5036-4572 en https://doi.org/10.1007/s00269-017-0937-7 Physics and Chemistry of Minerals Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Springer-Verlag GmbH Germany, part of Springer Nature application/pdf Springer Berlin Heidelberg Springer Berlin Heidelberg |
| spellingShingle | Berry, Andrew Jackson, Ian Garapić, Gordana Cline II, Christopher J. Faul, Ulrich Constraints on oxygen fugacity within metal capsules |
| title | Constraints on oxygen fugacity within metal capsules |
| title_full | Constraints on oxygen fugacity within metal capsules |
| title_fullStr | Constraints on oxygen fugacity within metal capsules |
| title_full_unstemmed | Constraints on oxygen fugacity within metal capsules |
| title_short | Constraints on oxygen fugacity within metal capsules |
| title_sort | constraints on oxygen fugacity within metal capsules |
| url | http://hdl.handle.net/1721.1/116932 https://orcid.org/0000-0001-5036-4572 |
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