M.Sc. Tezi Görüntüleme

      Ophiolitic chromitites from southeastern Turkey are located within the mainly mantle peridotites (harzburgite and dunite) in the form of veinlets and lenticular bodies. Chromitites show a wide variation of Cr composition (Cr# = 39&#8211;82), range between 42 and 348 ppb (mean 135 ppb) in total PGE concentrations. High&#8211;Cr chromitites (Cr# > 70; Mg# = 45.3&#8211;67) mainly contain low TiO2 (&#8804;0.2 %wt.) and higher total PGE contents (mean 158 ppb), whereas low&#8211;Cr ones (Cr# < 70; Mg# = 57.2&#8211;75.2) contain higher TiO2 contents (0.2&#8211;0.4 %wt.) and represented lower total PGE contents (84 ppb) slightly. However, one sample in high&#8211;Cr composition show a significant enrichment in PGE up 2.7 ppm. PGM and BMM mineralogy suggests that chromites crystallized high temperature (1300oC&#8722;1000oC) and low &#402;S2 (&#8211;4) conditions. Chemical, mineralogical, trace element, calculated primitive melts composition in southeastern Turkey ophiolitic chromitites and also textural, mineralogical features of primary inclusions indicate that the high&#8211;Cr chromitites are crystallized out of boninitic melt in a subduction environment, whereas chromitites of high&#8211;Al composition are thought to crystallized either from the MORB type melt in mid oceanic ridge setting or back&#8211;arc environment.