M.Sc. Tezi Görüntüleme
Whole rock major and trace element abundances and mineral phases of rock samplesfrom Harmancik, NW-Turkey are investigated to understand the formation of the ultramafic
rocks which are supposed to be remnants of lithosphere of Neotethys Ocean.MgO concentrations correlated negatively with SiO2, Al2O3, CaO, V, Sc, Yb and Lu.
Al2O3 and CaO abundances are between 0.75-2.21 and 0.01-2.31 wt%, respectively andincrease with the increasing of clinopyroxene abundances.
Olivine compositions range from Fo0.89 to Fo0.92 and show no chemical zoning. NiOcontents vary between 0.27 and 0.53 wt.%, and MnO contents reach up to 0.20 wt.%,
indicating compositions similar to mantle olivine. Orthopyroxene has high Mg# (0.89-0.92)and contains thin exsolution lamellae of clinopyroxene in some cases. Composition range
between En8691 Wo05 and Fs811, with low content of CaO (0.232.65 wt.%). Al2O3concentrations show a wide variation between 1.47 and 4.95 wt.%. The Al2O3 contents in
clinopyroxene vary between 1.88 and 6.09 wt.% and Cr2O3 contents between 0.45 and 1.27wt.% with a Mg# comprised in the range of 0.90 and 0.95. They also contain up to 0.17 wt.%
TiO2 and 0.64 wt.% Na2O.Spinel grains are generally rich in Al, with the Cr# and Mg# ranging from 0.18 to
0.56, and 0.5 to 0.79 respectively. Mg# of spinel is usually higher in clinopyroxene-richharzburgite than those of more depleted harzburgite and inversely correlated with the Cr#.
Whole rock MgO and V concentrations, as well as mineral chemistry imply that theserocks formed by different degrees of partial melting (%5-25). The clinopyroxene rich samples
have higher REE abundances than those of clinopyroxene poor ones and all samples aredepleted with respect to chondrite showing convex-downward patterns. Mineral chemistry
and whole rock abundances, as well as lack of abundant chromite deposits in the investigatedarea, reflect that ultramafic rocks of Harmancik are similar to the abyssal peridotites and have
not been affected intensively by percolating melt if SSZ origin is considered for the formationof these rocks.
Key Words: NW-Turkey, Harmancik (Bursa), Harzburgite, Supra Subduction Zone, PartialMelting