Magnetostratigraphy of the Baynunah Formation

The Baynunah Formation in the Al Gharbia region of Abu Dhabi Emirate was deposited by a major fluvial system and preserves the only known late Miocene terrestrial fossils in the Arabian Peninsula. We analyzed paleomagnetic samples from six sections (Jebel Barakah, Shuwaihat 2, Hamra 5, Mleisa 1, Mleisa 2, and Kihal 2) to develop a polarity stratigraphy for the Baynunah Formation. Based on these analyses, we documented a magnetic polarity stratigraphy, which, in combination with lithostratigraphy, allows us to propose a correlation of these six sections and their fossil localities. We show that first-order facies variations in the Baynunah Formation are diachronous. Confident correlations with the Geomagnetic Polarity Time Scale during the late Miocene cannot be determined; however, correlations based on the local polarity stratigraphy and biostratigraphy suggests that the Baynunah Formation was deposited over a duration of less than 750 kyr between ~7.7 and ~7.0 Ma during the late Tortonian and early Messinian. These results suggest that the fossil sites occurring throughout the lower part of the Baynunah unit and the fossil trackway sites found in the upper part of the formation are likely no more than a few hundred thousand years apart and could have been generated by the same taxa.