University of Isfahan Petrological Journal 2228-5210 12 2 2021 08 23 Evolution history of north Anarak, Central Iran ophiolitic olistoliths using petrographical and mineral chemistry studies Evolution history of north Anarak, Central Iran ophiolitic olistoliths using petrographical and mineral chemistry studies 125 148 25925 10.22108/ijp.2021.127663.1225 FA Elahe Zarei Ph.D. Student, Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Morteza Sharifi Associate Professor, Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Meisam Tadayon Assistant Professor, Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Journal Article 2021 03 03 Anarak ophiolite, belonging to Paleozoic, formed along with the tectonic evolution of the Paleo- Tethys Ocean, consisting of meta- peridotites of mantle and crust, cumulate rocks, massive gabbros, pillow lava, basic and ultrabasic dikes, rodingite and listwanite covered all by schist and marble units. The olistolithic patches of Anarak ophiolite have commonly exposed in Sebarz schist, within the sole of Chah-Gorbeh complex. Olistoliths composed of listwanite, meta- mafic, serpentinite and meta- peridotite olistoliths varying from centimeter to several hundred meters in size. The results of electron microprobe analyses show that the fundamental rock- forming minerals of the listwanitized olistoliths are chromian spinel and pyroxene, secondary minerals including calcite, garnet, tremolite, chlorite, magnetite and opaque minerals. Meta- mafic olistoliths composed of chromian spinel, sphene, epidote, chlorite and opaque minerals. Serpentinized olistoliths consist of chromian spinel, magnetite, tremolite, talc and chlorite. It also shows that the meta- peridotite olistoliths composed of chromian spinel, chrome-bearing magnetite, chlorite, calcite, garnet and antigorite. Based on the geochemical analyses, Cr# in the listwanite patches, meta- mafic, serpentinite and meta- peridotite olistoliths are 87.40- 97.92, 49.38- 51.89, 49.22- 60.05 and 29.76- 55.97 respectively with very low amount of TiO₂. The different in chemical composition of minerals in the North Anarak complex shows different petrogenesis for ophiolitic olistoliths suggests characteristic of the MORB and/or supra- subduction zone. Anarak ophiolite, belonging to Paleozoic, formed along with the tectonic evolution of the Paleo- Tethys Ocean, consisting of meta- peridotites of mantle and crust, cumulate rocks, massive gabbros, pillow lava, basic and ultrabasic dikes, rodingite and listwanite covered all by schist and marble units. The olistolithic patches of Anarak ophiolite have commonly exposed in Sebarz schist, within the sole of Chah-Gorbeh complex. Olistoliths composed of listwanite, meta- mafic, serpentinite and meta- peridotite olistoliths varying from centimeter to several hundred meters in size. The results of electron microprobe analyses show that the fundamental rock- forming minerals of the listwanitized olistoliths are chromian spinel and pyroxene, secondary minerals including calcite, garnet, tremolite, chlorite, magnetite and opaque minerals. Meta- mafic olistoliths composed of chromian spinel, sphene, epidote, chlorite and opaque minerals. Serpentinized olistoliths consist of chromian spinel, magnetite, tremolite, talc and chlorite. It also shows that the meta- peridotite olistoliths composed of chromian spinel, chrome-bearing magnetite, chlorite, calcite, garnet and antigorite. Based on the geochemical analyses, Cr# in the listwanite patches, meta- mafic, serpentinite and meta- peridotite olistoliths are 87.40- 97.92, 49.38- 51.89, 49.22- 60.05 and 29.76- 55.97 respectively with very low amount of TiO₂. The different in chemical composition of minerals in the North Anarak complex shows different petrogenesis for ophiolitic olistoliths suggests characteristic of the MORB and/or supra- subduction zone. https://ijp.ui.ac.ir/article_25925_9f7960adb89bd70076b8880e97fb2049.pdf