Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman

摘要: A vast bajada consisting of coalescing low-gradient (< 0.3°) alluvial fans exceeding 100 km in length formed along the southwestern margin Oman Mountains. It comprises an old fan sequence inferred Miocene to Pliocene age termed Barzaman Formation, diagenetically highly altered dolomitic clays, and a thin veneer weakly cemented Quaternary gravels. combination remote sensing, lithological analyses luminescence dating is used interpret complex aggradation history from interior context independent regional climate records. From satellite imagery clast analysis four can be discerned study area. While two early periods formation are tentatively correlated Miocene–Pliocene Early Pleistocene, allows distinction five phases during Middle–Late Pleistocene. These with pluvial Marine Isotope Stage (MIS) 11 through 3, when southern Arabia was affected by monsoonal precipitation. concluded that triggered interplay increased sediment production arid high rainfall enhanced erosion hillslopes transport rates strong monsoon phases. However, lack fine-grained sediments, bioturbation organic material implies although sourced rains they semi-arid environment. Thus, it appears that, contrast Mountains, not directly