Application of Geochemical Data as Evidence of Water-Rock Interaction in the Sarvak Formation, Izeh Zone, Zagros, Iran☆

The Sarvak formation from the Bangestan group is an important petroleum reservoir in Iran that we studied geochemically in 5 outcrop sections in the Izeh zone. Our results show that characteristics of the Sarvak Formation changed in the Izeh zone. High Sr/Mn ratios and Sr content with heaviest oxygen isotopes of the Sarvak Formation carbonates indicate lower dissolution processes, extensive rock-water interaction (WRI), and a closed diagenetic system. O and C isotope variations suggest marine phreatic diagenesis in the north flank of the Mish, Bangestan, and Mangasht anticlines, and meteoric diagenesis in the south flank of the Mish and Payun anticlines. Observed geochemical variations in the Izeh zone can be related to reactivation of deep-seated structures and faults that caused variation in thickness, facies, and diagenesis.