The Mila Formation is one of the Cambrian formations in Alborz. The Mila Formation has 5 measurable members in type section (Mila Kuh, Damghan City). This formation overlies conformably the Early Cambrian Lalun Formation and underlies disconformably the Early Devonian red conglomerates. But on the Chalus road in Central Alborz, four members of this formation are visible and measurable.
The first member is a white base quartzite (BQ), which in the past was a member of the lower formation (Lalun), but according to detailed studies, the boundary of this unit with underlying sandstone layers is considered to be discontinuous.
The Second member consist of Dolomite with interbedded of yellow Shale and Marl. Third member is well bedded Limestone with a few shale. Forth member is course grained glauconitic limestone. Fifth member consist of Siltstone, Sandstone, Glauconitic limestone and Marl.
In the Image, Mila formation outcrops in Chaloos road, near Hasanakdar Village. Because of the tectonic forces, the rocky layers are cut, broken, and displaced by faults.
The lower boundary of this formation with the Lalun Formation is para unconformity and indicated with the white quartzite layers. The upper boundary of this formation in this area is determined by the Hassanakdar fault and the outcrop of lava in the Geirud Formation. All the thickness of the Mila Formation (without quartzite) in the Karaj valley is 395 meters (Lorenz, 1964). In this region without the quartzite member, only three members of the Mila Formation have been identified.
In the photo, the formations of Lalun (La), Mila (Mi), Ruteh (Ru), Jeyrud (Je), Elika (El) and quartzite member of the Mila Formation (BQ) are seen.
Keywords: Iran , Central Alborz , Geology , Geotourism , formation , Mila , ruteh , jeyrud , elika , chaloos road , limestone , sandstone , siltstone , dolomite , shale , marl , zamingasht