The effect of tectonic on Middle Jurassic deposits, in Agh-Darband area, Kopet-Dagh basin, NE Iran

Emphasis on the association between tectonic and the formation of thick siliciclastic strata has tended to downplay the significance of high sediment supply and its potential to create deep-water fans. The Kashafrud Formation provides an excellent opportunity to study the interplay between deep-water sedimentation and syn-depositional tectonic subsidence (or uplift) in the region, and suggests that high supply was critical in causing the accretion of this moderately wide Middle Jurassic shelf margin, and the generation of large, sand-rich fans. The ~2 km of Kashafrud strata in the basin were deposited within ~ 6.9 million years. This rapid rate of deposition implies active subsidence and high rates of sediment supply during early basin filling.