After Pyrenean orogeny, central of Iran was under the influence of weathering and erosion. Caused materials were deposited in alluvial environments, floodplains or temporary tropical lakes.
These deposits are located between the upper Eocene rocks (mostly pyroclastic and igneous rocks) and Late Oligocene in “Central Iran” (one of the tectonostratigraphy state of Iran plateau) as “Lower red formation” are known.
The “Lower red” was first proposed by Ganser for the red deposits between Eocene volcano-sedimentary rocks and Oligocene-Miocene marine layers (Qom formation) in 1955.
This formation represents the red Oligocene continental deposits in west of Central Iran, particularly are widespread in Qom, Tafresh, southeast of Tehran, north of Garmsar and north of Semnan .
The picture was taken from Lower red formation near Ghezeljeh village in the 20 kilometers northwest of the Tafresh. In this area, the alternation of red sandy marl and conglomerates with intercalations of green and gray sandstone are deposited that called Lower red formation.
Oligomiocene sandstone was located on the Lower red formation with unconformity.