Cr-spinel compositions and the petrogenesis of podiform chromitites in the Kağızman Ophiolite (Ağrı, Eastern Türkiye)
GEOLOGICA CARPATHICA INTERNATIONAL GEOLOGICAL JOURNAL, cilt.77, sa.4, ss.275-289, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 77 Sayı: 4
- Basım Tarihi: 2026
- Doi Numarası: 10.31577/geolcarp.2026.14
- Dergi Adı: GEOLOGICA CARPATHICA INTERNATIONAL GEOLOGICAL JOURNAL
- Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Earth, Atmospheric, & Aquatic Science Collection (ProQuest), Scopus, Science Citation Index Expanded (SCI-EXPANDED), BIOSIS, Geobase, Directory of Open Access Journals
- Sayfa Sayıları: ss.275-289
- Van Yüzüncü Yıl Üniversitesi Adresli: Evet
Özet
Podiform chromitites are important indicators of mantle processes associated with subduction initiation, yet their formation mechanisms remain debated. This study presents petrographic and mineral-chemical data from chromitites of the Eastern Ağrı region (Kağızman Ophiolite) in the eastern segment of the İzmir–Ankara–Erzincan Suture Zone and evaluates their significance for supra-subduction zone (SSZ) forearc mantle evolution along the northern NeoTethyan margin. The chromitites occur as massive and disseminated bodies hosted by dunite channels within refractory harzburgite. Sharp spinel grain boundaries and primary silicate inclusions (orthopyroxene ± olivine) preserved within Cr-spinel cores indicate focused melt flow, melt–rock interaction, and chromitite saturation in a forearc mantle setting. Cr-spinels are characterized by high Cr# values (0.57–0.88) and low TiO2 contents (<0.7 wt.%), whereas olivine (Fo90–93) and orthopyroxene (Mg# = 90–94) compositions indicate a strongly depleted mantle source. Field relationships, petrography, and mineral chemistry suggest that chromitite formation occurred during subduction initiation and was related to slab-derived fluid influx and hydrous melting of refractory mantle. The coexistence of different chromitite textures and preserved primary mineral signatures indicates a multi-stage chromitite-forming process linked to evolving melt fluxes. Comparison with other Neo-Tethyan and global ophiolitic chromitites supports an SSZ affinity for the Kağızman chromitites and highlights the role of integrated petrographic and mineral-chemical approaches in constraining chromitite genesis and forearc mantle evolution.