Identification of Falling Stage System Tract in fluvial successions, an example from Shurijeh Formation

Identification of falling-stage system tracts (FSST) in sequence stratigraphy has important role in sequence boundary recognition and exploration researches. However, formation and preservation chance of its related facies in the fluvial successions is very low. This study pays to signs and evidence of identification of the FSST in sequence stratigraphy with an example from Lower Cretaceous fluvial Shurijeh Formation in the east Kopeh Dagh Basin. Integration of 3D seismic data with boreholes data from seven wells and four outcrop sections (Shurijeh Village, Anjeer-Bulagh, Mozduran Pass and Qorqoreh) used in this study. Results show that during Late Jurassic-Early Cretaceous marine regression fine-grained and hybrid carbonate-siliciclastic facies in the base of the Shurijeh Formation are belong to falling stage system tract. These facies deposited in low energy condition in flood plain and coastal plain, related to the shoreline trajectory. Based on seismic stratigraphic study, fluvial system tocks place and channels created in the basin, during sea/base level forced regression. Quantitative seismic geomorphological analyses indicate that existed channels were hydraulically as bypassing channels.