oxygen and hydrogen isotope study of serpentinized peridotite rocks, thrust zone, north east iraq

Abstract

This study concentrates on two serpentinite bodies (Mawat and Penjwin) within Zagros Thrust Zone, North East Iraq. The Mawat Serpentinite which represents lherzolite protolith show δ18O of 6.77 – 8.33 %o and δD values of (-65) - (-61) %o. The Penjwin serpentinite (harzburgite protolith) show δ18O values of 10.90 – 13.29 %o and δD values of (-74) – (-69) %o. Mawat serpentinization occurred by hydration of mantle wedge rocks along intraoceanic supra-subduction zone at temperature of 150 – 200 oC. On the other hand Penjwin serpentinization occurred during and after emplacement of Penjwin ophiolite suite at temperature of 50 – 100 oC. Emplacement of Mawat serpentinite as an isolated body into Walash volcano-sedimentary sequence took place by diapiric process. Penjwin serpentinite was emplaced due to tectono-metamorphic event.