LAUSR

Abstract Syntectonic deposits of the Mesopotamian flexural basin have been dated in the Lurestan and Fars salients in the Zagros foldbelt since the early 2000's but not in the Dezful embayment where most of the Zagros foreland oil is trapped. We use 237 samples collected for magnetostratigraphy to date shallow marine to fluvial-alluvial pre-growth and growth strata deposits along a >2700 m section in the NE flank of the Jarik anticline in north Dezful embayment. The Jarik anticline grew by a combination of compression and coeval diapirism like other structures in north Dezful embayment. The correlation of the local magnetostratigraphy with the Geomagnetic Polarity Time Scale indicates ages of 14.1 Ma and ~13.6 Ma for the bases of the Mishan and Aghajari formations. The bases of Lahbari Mb. and Bakhtyari Fm. are ~9.0 Ma and ~7.0 Ma. The onset of growth strata in the NE flank of the Jarik anticline is ~12.8 Ma with a duration of 5.8 Myr for this anticline. This study presents for the first time the age of syntectonic deposition and folding in the Dezful embayment that is essential to determine burial and generation of hydrocarbons in this oil-rich province.