Petrological characteristics and geochemical compositions of the Neotethyan Mersin ophiolite (southern Turkey): Processes of melt depletion, refertilization, chromitite formation and oceanic crust generation


SAKA S. , UYSAL İ. , Kapsiotis A., Bagci U., Ersoy E. Y. , Su B., ...Daha Fazla

JOURNAL OF ASIAN EARTH SCIENCES, cilt.176, ss.281-299, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 176
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.jseaes.2019.01.003
  • Dergi Adı: JOURNAL OF ASIAN EARTH SCIENCES
  • Sayfa Sayıları: ss.281-299

Özet

The Mersin ophiolite of the Central Taurides in southern Turkey represents an incomplete section of ocean lithosphere consisting from bottom to top of chromitite-bearing mantle peridotites, cumulate dunites, clinopyroxenites, and gabbros with rare pillow lavas covered by bathypelagic sedimentary rocks. The tectonized peridotites are harzburgites with minor dunites. They are strongly melt-depleted peridotites, comprising chromian spinel (Cr-spinel) with medium to high Cr-numbers (Cr#) [100 x Cr/(Cr + Al) = 48-82] and low Al2O3 concentrations (0.05-2.2 wt%). They display concave chondrite-normalized rare earth element (REE) patterns, which we interpret as evidence for their refertilization by boninitic melts in a mantle wedge. Geochemical evidence suggests that the parental magmas of the high-Cr podiform chromitites (Cr#(sp) = 71-83) were of boninitic composition. The chromitites host a platinum-group mineral (PGM) assemblage of laurite [Ru#-64.0-90.7] and Os-Ir alloys, indicating crystallization within a range of low fS(2) conditions (logfS(2) similar to -2 to -1.3) and a T-max of similar to 1200 degrees C.