View in EDS

Mg–K isotopic compositions deciphering mantle heterogeneity beneath southeast Tibet.

Saved in:
Bibliographic Details
Title: Mg–K isotopic compositions deciphering mantle heterogeneity beneath southeast Tibet.
Authors: Chen, Qiong1 (AUTHOR), Cheng, Hao1 (AUTHOR) chenghao@tongji.edu.cn, Zhao, Guo-Chun1,2 (AUTHOR) gzhao@hku.hk, Zhou, Mei-Fu3 (AUTHOR), Liu, Ping-Ping4 (AUTHOR), Li, Wen-Jun5 (AUTHOR), Sun, Min2 (AUTHOR)
Source: Geochimica et Cosmochimica Acta. Jun2026, Vol. 422, p164-178. 15p.
Subjects: Earth's mantle, Metasomatism, Magmatism, Magnesium isotopes, Volcanism, Slabs (Structural geology)
Geographic Terms: Tibet (China)
Abstract: The mantle compositional heterogeneity beneath southeast Tibet peaked due to the incorporation of slab materials and intensive mantle-crust interaction. It remains uncertain regarding the differentiated mantle enrichment and elemental cycling process in a post-collisional setting. Here, we use stable Mg-K isotopic data from young (<5 Ma) arc-type and OIB-type basalts—spatially and genetically linked to slab subduction and stagnation—to quantify the origin, proportion, and transport mechanism of materials contributing to mantle heterogeneity. Both basaltic types from southeast Tibet possess homogeneous and low δ26Mg values (−0.39 ± 0.03 ‰ to −0.36 ± 0.04 ‰) compared to the normal mantle range (δ26Mg = −0.25 ± 0.04 ‰); Mg–Sr–Nd–Pb isotopic mixing models suggest that isotopically light marine carbonates were incorporated into the mantle wedge and mantle transition zone (MTZ). In terms of the isotopic dataset of post-collisional magmatic rocks, pervasive carbonatitic metasomatism served as the deep carbon source that enhanced mantle heterogeneity. Compared to the mantle-like δ41K (−0.49 ± 0.04 ‰ to −0.35 ± 0.02 ‰) of arc-type samples that re-homogenized in the wedge, the OIB-type lavas have variable δ41K values (−0.73 ± 0.03 ‰ to −0.54 ± 0.02 ‰) lower than those of primitive mantle (δ41K = −0.42 ± 0.08 ‰), suggesting an increased release of isotopically light K from dehydrated Neo-Tethyan slab residues that stagnated in the MTZ. Geophysical evidence supports that these deep-seated metasomatic agents triggered wet upwelling flows atop the MTZ and transported surficial materials back via volcanism. Critically, this study constrains the origin of mantle heterogeneity and material circulation triggered by various contributions of the subducted plate. [ABSTRACT FROM AUTHOR]
Copyright of Geochimica et Cosmochimica Acta is the property of Pergamon Press - An Imprint of Elsevier Science 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
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 194522229
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Mg–K isotopic compositions deciphering mantle heterogeneity beneath southeast Tibet.
– Name: Author
  Label: Authors
  Group: Au
  Data: &lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Chen%2C+Qiong%22&quot;&gt;Chen, Qiong&lt;/searchLink&gt;&lt;relatesTo&gt;1&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Cheng%2C+Hao%22&quot;&gt;Cheng, Hao&lt;/searchLink&gt;&lt;relatesTo&gt;1&lt;/relatesTo&gt; (AUTHOR)&lt;i&gt; chenghao@tongji.edu.cn&lt;/i&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Zhao%2C+Guo-Chun%22&quot;&gt;Zhao, Guo-Chun&lt;/searchLink&gt;&lt;relatesTo&gt;1,2&lt;/relatesTo&gt; (AUTHOR)&lt;i&gt; gzhao@hku.hk&lt;/i&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Zhou%2C+Mei-Fu%22&quot;&gt;Zhou, Mei-Fu&lt;/searchLink&gt;&lt;relatesTo&gt;3&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Liu%2C+Ping-Ping%22&quot;&gt;Liu, Ping-Ping&lt;/searchLink&gt;&lt;relatesTo&gt;4&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Li%2C+Wen-Jun%22&quot;&gt;Li, Wen-Jun&lt;/searchLink&gt;&lt;relatesTo&gt;5&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Sun%2C+Min%22&quot;&gt;Sun, Min&lt;/searchLink&gt;&lt;relatesTo&gt;2&lt;/relatesTo&gt; (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: &lt;searchLink fieldCode=&quot;JN&quot; term=&quot;%22Geochimica+et+Cosmochimica+Acta%22&quot;&gt;Geochimica et Cosmochimica Acta&lt;/searchLink&gt;. Jun2026, Vol. 422, p164-178. 15p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: &lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Earth&#39;s+mantle%22&quot;&gt;Earth&#39;s mantle&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Metasomatism%22&quot;&gt;Metasomatism&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Magmatism%22&quot;&gt;Magmatism&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Magnesium+isotopes%22&quot;&gt;Magnesium isotopes&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Volcanism%22&quot;&gt;Volcanism&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Slabs+%28Structural+geology%29%22&quot;&gt;Slabs (Structural geology)&lt;/searchLink&gt;
– Name: SubjectGeographic
  Label: Geographic Terms
  Group: Su
  Data: &lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Tibet+%28China%29%22&quot;&gt;Tibet (China)&lt;/searchLink&gt;
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: The mantle compositional heterogeneity beneath southeast Tibet peaked due to the incorporation of slab materials and intensive mantle-crust interaction. It remains uncertain regarding the differentiated mantle enrichment and elemental cycling process in a post-collisional setting. Here, we use stable Mg-K isotopic data from young (&lt;5 Ma) arc-type and OIB-type basalts—spatially and genetically linked to slab subduction and stagnation—to quantify the origin, proportion, and transport mechanism of materials contributing to mantle heterogeneity. Both basaltic types from southeast Tibet possess homogeneous and low δ26Mg values (−0.39 &#177; 0.03 ‰ to −0.36 &#177; 0.04 ‰) compared to the normal mantle range (δ26Mg = −0.25 &#177; 0.04 ‰); Mg–Sr–Nd–Pb isotopic mixing models suggest that isotopically light marine carbonates were incorporated into the mantle wedge and mantle transition zone (MTZ). In terms of the isotopic dataset of post-collisional magmatic rocks, pervasive carbonatitic metasomatism served as the deep carbon source that enhanced mantle heterogeneity. Compared to the mantle-like δ41K (−0.49 &#177; 0.04 ‰ to −0.35 &#177; 0.02 ‰) of arc-type samples that re-homogenized in the wedge, the OIB-type lavas have variable δ41K values (−0.73 &#177; 0.03 ‰ to −0.54 &#177; 0.02 ‰) lower than those of primitive mantle (δ41K = −0.42 &#177; 0.08 ‰), suggesting an increased release of isotopically light K from dehydrated Neo-Tethyan slab residues that stagnated in the MTZ. Geophysical evidence supports that these deep-seated metasomatic agents triggered wet upwelling flows atop the MTZ and transported surficial materials back via volcanism. Critically, this study constrains the origin of mantle heterogeneity and material circulation triggered by various contributions of the subducted plate. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: &lt;i&gt;Copyright of Geochimica et Cosmochimica Acta is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder&#39;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.&lt;/i&gt; (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=194522229
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1016/j.gca.2025.10.010
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 15
        StartPage: 164
    Subjects:
      – SubjectFull: Earth's mantle
        Type: general
      – SubjectFull: Metasomatism
        Type: general
      – SubjectFull: Magmatism
        Type: general
      – SubjectFull: Magnesium isotopes
        Type: general
      – SubjectFull: Volcanism
        Type: general
      – SubjectFull: Slabs (Structural geology)
        Type: general
      – SubjectFull: Tibet (China)
        Type: general
    Titles:
      – TitleFull: Mg–K isotopic compositions deciphering mantle heterogeneity beneath southeast Tibet.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Chen, Qiong
      – PersonEntity:
          Name:
            NameFull: Cheng, Hao
      – PersonEntity:
          Name:
            NameFull: Zhao, Guo-Chun
      – PersonEntity:
          Name:
            NameFull: Zhou, Mei-Fu
      – PersonEntity:
          Name:
            NameFull: Liu, Ping-Ping
      – PersonEntity:
          Name:
            NameFull: Li, Wen-Jun
      – PersonEntity:
          Name:
            NameFull: Sun, Min
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 06
              Text: Jun2026
              Type: published
              Y: 2026
          Identifiers:
            – Type: issn-print
              Value: 00167037
          Numbering:
            – Type: volume
              Value: 422
          Titles:
            – TitleFull: Geochimica et Cosmochimica Acta
              Type: main
ResultId 1