Genesis and fate of incipient melt in shallow lower mantle.
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| Title: | Genesis and fate of incipient melt in shallow lower mantle. |
|---|---|
| Authors: | Khan, Siddharth1 (AUTHOR) siddharthkhan4@gmail.com, Andrault, Denis1 (AUTHOR) denis.andrault@uca.fr, Condamine, Pierre1 (AUTHOR), Schiavi, Federica1 (AUTHOR), Devidal, Jean-Luc1 (AUTHOR), Bolfan-Casanova, Nathalie1 (AUTHOR) |
| Source: | Contributions to Mineralogy & Petrology. Oct2025, Vol. 180 Issue 10, p1-16. 16p. |
| Subjects: | Earth's mantle, Melting, Dehydration reactions, Geophysical observations, Buoyancy |
| Abstract: | Geophysical observations have revealed the existence of low-velocity zones that potentially coincide with the ongoing downward flow of mantle material through the globally recognized sharp discontinuity at a depth of 670 km. The leading interpretation for these heterogeneities is related to dehydration induced incipient partial melting. Here, we have employed an iterative method to achieve equilibrium between melt pools and undifferentiated pyrolite at geotherm conditions, allowing for a precise determination of partitioning of the major components (SiO2-MgO-Al2O3-FeO-CaO) between the melt and minerals. The melt holds 5.5 (0.4) wt% H2O and is relatively mafic compared to its source material, with considerable enrichment in CaO and FeO. For the (shallow) lower mantle in hydrous conditions, the solidus phase is davemaoite, followed by ferropericlase, and bridgmanite becomes the liquidus phase. Density models show that such magma is positively buoyant in the shallow lower mantle. Thus, it is expected to travel upward and possibly freeze in the transition zone. This process implies that, over time, continuous dehydration of the downgoing slab and subsequent hydrous melt extraction from the lower mantle wedge limit the deep water cycle to the upper 670 km depth of the mantle. [ABSTRACT FROM AUTHOR] |
| Copyright of Contributions to Mineralogy & Petrology is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 188625405 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Genesis and fate of incipient melt in shallow lower mantle. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Khan%2C+Siddharth%22">Khan, Siddharth</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> siddharthkhan4@gmail.com</i><br /><searchLink fieldCode="AR" term="%22Andrault%2C+Denis%22">Andrault, Denis</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> denis.andrault@uca.fr</i><br /><searchLink fieldCode="AR" term="%22Condamine%2C+Pierre%22">Condamine, Pierre</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Schiavi%2C+Federica%22">Schiavi, Federica</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Devidal%2C+Jean-Luc%22">Devidal, Jean-Luc</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Bolfan-Casanova%2C+Nathalie%22">Bolfan-Casanova, Nathalie</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Contributions+to+Mineralogy+%26+Petrology%22">Contributions to Mineralogy & Petrology</searchLink>. Oct2025, Vol. 180 Issue 10, p1-16. 16p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Earth's+mantle%22">Earth's mantle</searchLink><br /><searchLink fieldCode="DE" term="%22Melting%22">Melting</searchLink><br /><searchLink fieldCode="DE" term="%22Dehydration+reactions%22">Dehydration reactions</searchLink><br /><searchLink fieldCode="DE" term="%22Geophysical+observations%22">Geophysical observations</searchLink><br /><searchLink fieldCode="DE" term="%22Buoyancy%22">Buoyancy</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Geophysical observations have revealed the existence of low-velocity zones that potentially coincide with the ongoing downward flow of mantle material through the globally recognized sharp discontinuity at a depth of 670 km. The leading interpretation for these heterogeneities is related to dehydration induced incipient partial melting. Here, we have employed an iterative method to achieve equilibrium between melt pools and undifferentiated pyrolite at geotherm conditions, allowing for a precise determination of partitioning of the major components (SiO2-MgO-Al2O3-FeO-CaO) between the melt and minerals. The melt holds 5.5 (0.4) wt% H2O and is relatively mafic compared to its source material, with considerable enrichment in CaO and FeO. For the (shallow) lower mantle in hydrous conditions, the solidus phase is davemaoite, followed by ferropericlase, and bridgmanite becomes the liquidus phase. Density models show that such magma is positively buoyant in the shallow lower mantle. Thus, it is expected to travel upward and possibly freeze in the transition zone. This process implies that, over time, continuous dehydration of the downgoing slab and subsequent hydrous melt extraction from the lower mantle wedge limit the deep water cycle to the upper 670 km depth of the mantle. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Contributions to Mineralogy & Petrology is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s00410-025-02260-2 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 16 StartPage: 1 Subjects: – SubjectFull: Earth's mantle Type: general – SubjectFull: Melting Type: general – SubjectFull: Dehydration reactions Type: general – SubjectFull: Geophysical observations Type: general – SubjectFull: Buoyancy Type: general Titles: – TitleFull: Genesis and fate of incipient melt in shallow lower mantle. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Khan, Siddharth – PersonEntity: Name: NameFull: Andrault, Denis – PersonEntity: Name: NameFull: Condamine, Pierre – PersonEntity: Name: NameFull: Schiavi, Federica – PersonEntity: Name: NameFull: Devidal, Jean-Luc – PersonEntity: Name: NameFull: Bolfan-Casanova, Nathalie IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: Oct2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 00107999 Numbering: – Type: volume Value: 180 – Type: issue Value: 10 Titles: – TitleFull: Contributions to Mineralogy & Petrology Type: main |
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