Trace element mobility and mineral-scale redistribution during retrograde metamorphism of lawsonite-bearing high-pressure rocks from Elekdağ, Turkey
Contributions to Mineralogy and Petrology, cilt.181, sa.9, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 181 Sayı: 9
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s00410-026-02358-1
- Dergi Adı: Contributions to Mineralogy and Petrology
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Chemical Abstracts Core, Environment Index, Geobase, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Earth, Atmospheric, & Aquatic Science Collection (ProQuest), Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Eclogite, Fluid metasomatism, Lawsonite-bearing eclogite, Mass balance modelling, P–T–t evolution, Subduction zones, Trace element redistribution
- Dokuz Eylül Üniversitesi Adresli: Hayır
Özet
Subduction-zone metamorphism significantly influences trace element redistribution during burial and exhumation of oceanic lithosphere. We investigate high-pressure metamorphic rocks from the Elekdağ ophiolite (Turkey) using petrography, mineral chemistry, phase-equilibrium modelling, and rutile U–Pb geochronology. Phase-equilibrium modelling indicates peak conditions of 2.3–2.6 GPa and 530–600 °C, with rutile U–Pb dating constraining near-peak metamorphism at 102 ± 14 Ma, followed by blueschist-facies retrogression. Whole-rock geochemistry reveals that while some samples retain MORB-like compositions, others exhibit high field strength element (HFSE) depletion and large-ion lithophile element (LILE; e.g., K, Rb, Ba, B) enrichment. Phengite-hosted LILE enrichment points to open-system fluid infiltration, likely reflecting a combination of protolith seafloor alteration and retrograde metasomatism. Semi-quantitative mass-balance calculations and mineral-scale data indicate that trace element features reflect scale-dependent processes. Locally, light rare earth elements (LREEs), Sr, and HFSEs were predominantly redistributed during the breakdown of lawsonite to clinozoisite/epidote via interface-coupled dissolution–reprecipitation. Although LREEs and Sr are traditionally fluid-mobile, their high sequestration into these newly formed phases suggests restricted, localized mobility, though minor matrix-scale external fluid exchange cannot be entirely ruled out. These findings highlight a scale-dependent decoupling of element mobility and demonstrate that whole-rock geochemical signatures in retrogressed high-pressure rocks integrate protolith inheritance, open-system fluid overprinting, and mineral-scale redistribution. Relying solely on bulk geochemistry may thus lead to the misinterpretation of subduction-zone fluid-rock dynamics without integrating detailed mineral-scale budgets.