Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths
Abstract Jeffbenite (having the same chemical composition of pyrope, ~ Mg3Al2Si3O12, and also known as TAPP phase) is a mineral inclusion only found in diamonds formed between about 300 and 1000 km depth) and is considered a stable phase in the transition zone (410–660 km depth) and/or in the shallo...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-01-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-27290-9 |
| _version_ | 1797864667330117632 |
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| author | Fabrizio Nestola Mauro Prencipe Donato Belmonte |
| author_facet | Fabrizio Nestola Mauro Prencipe Donato Belmonte |
| author_sort | Fabrizio Nestola |
| collection | DOAJ |
| description | Abstract Jeffbenite (having the same chemical composition of pyrope, ~ Mg3Al2Si3O12, and also known as TAPP phase) is a mineral inclusion only found in diamonds formed between about 300 and 1000 km depth) and is considered a stable phase in the transition zone (410–660 km depth) and/or in the shallowest regions of the lower mantle (around 660–700 km depth). This rare and enigmatic mineral is considered to be a pressure marker for super-deep diamonds and therefore it has a key role in super-deep diamond research. However, the pressure–temperature stability fields for Mg3Al2Si3O12 jeffbenite is unknown and its actual formation conditions remain unexplored. Here we have determined the thermodynamic pressure–temperature stability field for the jeffbenite Mg-end member and surprisingly discovered that it is stable at low pressure–temperature conditions, i.e., 2–4 GPa at 800 and 500 °C. Thus, Mg3Al2Si3O12 jeffbenite is not the high-pressure polymorph of pyrope and is likely a retrogressed phase formed during the late ascent stages of super-deep diamonds to the surface. |
| first_indexed | 2024-04-09T22:55:37Z |
| format | Article |
| id | doaj.art-f9f5034c19af47659a41b010be279fd5 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-09T22:55:37Z |
| publishDate | 2023-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-f9f5034c19af47659a41b010be279fd52023-03-22T11:18:31ZengNature PortfolioScientific Reports2045-23222023-01-0113111010.1038/s41598-022-27290-9Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depthsFabrizio Nestola0Mauro Prencipe1Donato Belmonte2Dipartimento di Geoscienze, Università degli Studi di PadovaDipartimento di Scienze della Terra, Università degli Studi di TorinoDipartimento di Scienze della Terra, dell’Ambiente e della Vita, Università degli Studi di GenovaAbstract Jeffbenite (having the same chemical composition of pyrope, ~ Mg3Al2Si3O12, and also known as TAPP phase) is a mineral inclusion only found in diamonds formed between about 300 and 1000 km depth) and is considered a stable phase in the transition zone (410–660 km depth) and/or in the shallowest regions of the lower mantle (around 660–700 km depth). This rare and enigmatic mineral is considered to be a pressure marker for super-deep diamonds and therefore it has a key role in super-deep diamond research. However, the pressure–temperature stability fields for Mg3Al2Si3O12 jeffbenite is unknown and its actual formation conditions remain unexplored. Here we have determined the thermodynamic pressure–temperature stability field for the jeffbenite Mg-end member and surprisingly discovered that it is stable at low pressure–temperature conditions, i.e., 2–4 GPa at 800 and 500 °C. Thus, Mg3Al2Si3O12 jeffbenite is not the high-pressure polymorph of pyrope and is likely a retrogressed phase formed during the late ascent stages of super-deep diamonds to the surface.https://doi.org/10.1038/s41598-022-27290-9 |
| spellingShingle | Fabrizio Nestola Mauro Prencipe Donato Belmonte Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths Scientific Reports |
| title | Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths |
| title_full | Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths |
| title_fullStr | Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths |
| title_full_unstemmed | Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths |
| title_short | Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths |
| title_sort | mg3al2si3o12 jeffbenite inclusion in super deep diamonds is thermodynamically stable at very shallow earth s depths |
| url | https://doi.org/10.1038/s41598-022-27290-9 |
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