<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>El Korh, Afifé</dc:creator>
  <dc:creator>Luais, Béatrice</dc:creator>
  <dc:creator>Deloule, Etienne</dc:creator>
  <dc:creator>Cividini, Damien</dc:creator>
  <dc:date>2017-06-01</dc:date>
  <dc:description xmlns:ns0="xml" ns0:lang="en">Characterisation of mass transfer during subduction is fundamental to understand the origin of compositional heterogeneities in the upper mantle. Fe isotopes were measured in high-pressure/low-temperature metabasites (blueschists, eclogites and retrograde greenschists) from the Ile de Groix (France), a Variscan high-pressure terrane, to determine if the subducted oceanic crust contributes to mantle Fe isotope heterogeneities. The metabasites have δ56Fe values of +0.16 to +0.33‰, which are heavier than typical values of MORB and OIB, indicating that their basaltic protolith derives from a heavy-Fe mantle source. The δ56Fe correlates well with Y/Nb and (La/Sm)PM ratios, which commonly fractionate during magmatic processes, highlighting variations in the magmatic protolith composition. In addition, the shift of δ56Fe by +0.06 to 0.10‰ compared to basalts may reflect hydrothermal alteration prior to subduction. The δ56Fe decrease from blueschists (+0.19 ± 0.03 to +0.33 ± 0.01‰) to eclogites (+0.16 ± 0.02 to +0.18 ± 0.03‰) reflects small variations in the protolith composition, rather than Fe fractionation during metamorphism: newly- formed Fe-rich minerals allowed preserving bulk rock Fe compositions during metamorphic reactions and hampered any Fe isotope fractionation. Greenschists have δ56Fe values (+0.17 ± 0.01 to +0.27 ± 0.02‰) similar to high-pressure rocks. Hence, metasomatism related to fluids derived from the subducted hydrothermally altered metabasites might only have a limited effect on mantle Fe isotope composition under subsolidus conditions, owing to the large stability of Fe-rich minerals and low mobility of Fe. Subsequent melting of the heavy-Fe metabasites at deeper levels is expected to generate mantle Fe isotope heterogeneities.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>https://folia.unifr.ch/global/documents/306039</dc:identifier>
  <dc:identifier>https://folia.unifr.ch/documents/306039/files/koh_iif.pdf</dc:identifier>
  <dc:identifier>https://folia.unifr.ch/documents/306039/files/koh_iif_sm.pdf</dc:identifier>
  <dc:language>eng</dc:language>
  <dc:relation>info:eu-repo/semantics/altIdentifier/doi/10.1007/s00410-017-1357-x</dc:relation>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>License undefined</dc:rights>
  <dc:source>Contributions to Mineralogy and Petrology. - 2017, vol. 172, no. 6, p. 41</dc:source>
  <dc:subject xmlns:ns1="xml" ns1:lang="en">Fe isotopes</dc:subject>
  <dc:subject xmlns:ns2="xml" ns2:lang="en">Metabasites</dc:subject>
  <dc:subject xmlns:ns3="xml" ns3:lang="en">Subduction</dc:subject>
  <dc:subject xmlns:ns4="xml" ns4:lang="en">HP-LT metamorphism</dc:subject>
  <dc:subject xmlns:ns5="xml" ns5:lang="en">Blueschists</dc:subject>
  <dc:subject xmlns:ns6="xml" ns6:lang="en">Eclogites</dc:subject>
  <dc:subject xmlns:ns7="xml" ns7:lang="en">Greenschists</dc:subject>
  <dc:subject xmlns:ns8="xml" ns8:lang="en">Basaltic protoliths</dc:subject>
  <dc:subject>info:eu-repo/classification/udc/549</dc:subject>
  <dc:title xmlns:ns9="xml" ns9:lang="en">Iron isotope fractionation in subduction-related high-pressure metabasites (Ile de Groix, France)</dc:title>
  <dc:type>http://purl.org/coar/resource_type/c_6501</dc:type>
</oai_dc:dc>