Identification and description of the upper Neogene palustrine sediments in the east of Damghan

The studied area is a silty-clayey sedimentary landform, which is located on the border of Alborz and Central Iran sedimentary-structural units. It has 13 km long in the vicinity of the road Damghan to Shahroud. An integration of sedimentological and palynological studies is used for palaeoenvironmental interpretation, origin investigation, and age dating of the landform sediments. The presence of transparent and angular quartzes and unstable minerals and the abundance of organic matter in the landform sediments indicate an aquatic environment in which a series of erosion events to sedimentation has taken place in a short period of time. A combination of sedimentological investigations and palynological studies such as the organic matter preservation factors and the presence of index dinocysts such as Operculodinium cf. eiricianum and Bitectatodinium tepikiense which are characteristic of the shallow aqueous environment, a palustrine environment with brackish water in with an age of Late Neogene is assigned for the studied sediments. This relatively vast aqueous environment was related to the Haj Ali Qoli salt playa (Chah Jam playa) in the south of the studied region. These sediments were developed on a mud flat zone on the northern margin of this playa. Uplifting and exposure of this sedimentary landform could be due to the tectonic activity of the region and the movement of the left-lateral strike-slip of the eastern part of the Damghan Fault.