Sedimentary reservoir study of the Sarvak Formations and recognatin of its boundary with Ilam Formation by geochemical data in Chenareh anticline, south of Lorestan

The Sarvak Formation with Albian to Cenomanian ages is one of the main carbonate reservoir in Iran which spreated in the Zagros Basin throughout the Persian Gulf. In the current research an outcrope section of the Sarak Formation with a 477 m thickness in Chenareh anticline, South of Lorestan was studied. The lithology of the Sarvak Formation in studied area was massive, medium to thin bedded limestones. The upper boundary of the Sarvak Formation with the Ilam Formation was not recognizable due to similar lithogy, however with carboan isotope data and trace and major elements the boundary was determined. The geochemical evidance indicate that the Cenomanian- Turonian boundary was correlated with global data. Sedimentological studies and facies analysis of 166 thin sections of the Sarvak Formation in Chenareh Anticline was led to determination of 12 microfacies that are deposited in 4 facies belts including tidal falt, lagoon, shoal and open marine envronments. According to recognized microfacies and comparing with standard facies, lack of reef structures, sliding and slumping facies, the sediment environment of this formation was distinguishe as a carbonate ramp. Digenetic processes which affected the Sarvak Formation in Chenareh anticline includes cementation, dolomitization, dissolution, compaction, stylolitization, neomorphism, micritization, ferronization, bioturbation and silicification. Based on cathodoluminescence study the cements of the Sarvak Formation are formed in there meteoric, burial, and marine diagenesis environments.