Petrology and Mineralogy of Serpentinite Rock from the Mawat Ophiolite Complex in Zagros Suture Zone, Betwat Area, NE Iraq

This study aims to investigate the serpentinite rocks by combining field observation, petrographic and mineralogical aspects to deduce the mineral composition origin and tectonic setting of the serpentinized ultramafic rocks from Mawat ophiolite complex in Zagros Suture Zone, northern Iraq. The studied rocks are completely serpentinized samples characterized by mineral assemblages consisting of serpentine with relics of the original minerals: olivine and pyroxene, with other subordinate minerals such as amphibole, talc, chlorite, chromite, and magnetite. The serpentine mineral appears in three types (chrysotile, lizardite, and antigorite). The most common mineral is antigorite, which refers to a two-serpentinization stage. The first is retrogression of the original minerals (olivine and pyroxene) by hydrothermal solution to chrysotile and lizardite, and the second stage is a progressive metamorphism, which has recrystallized these minerals into antigorite. The chemistry of the studied minerals reveals that serpentine has a high MgO content, Mg-rich amphibole (type tremolite and actinolite), and chlorite is talc-chlorite type, which indicates a high MgO content. Chromite has elevated Cr2O3 relative to Al2O3 content, which indicates chromitite. Low Al to Cr ratios resemble ophiolitic podiform chromite, especially those seen in dunite. High Cr# and Mg# represent mantle-derived peridotites.