A part of the Nakhlak area (NE. Nain, Central Iran) to the west of central Iran desert was studied. The Triassic rocks of the Nakhlak area with a thickness of 2701 meters are divided into 3 Formations: Alam Formation, Baqoroq Formation and Ashin Formation. Outcrops of these rocks are bounded by two thrust faults.
     The Alam Formation (1298 m.) with Late Scythian- Middle Anisian age consists of carbonate facies at the base and turbiditic clastic facies (dominantly sandstone and shale) at the top. Carbonate facies rocks were derived from the continental shelf and the elastic facies rocks were dominantly derived from the continental slope as submarine fanlomerates. The Alam Formation was thrusted over the ophiolitic rocks of the Nakhlak area and was covered by Baqoroq Formation with a disconform contact.  The Baqoroq Formation (1122m) with Late Anisian? - Middle Ladinian age dominantly consists of conglomerate, sandstone and shale.
    These facies were derived from a continental environment and deposited as alluvial fans, by meandering and braided rivers. The Baqoroq Formation (281 m) with Late Ladinian-Early Carnian? age consists of elastic facies (dominantly sandstone and shale) deposited at the end of continental slope to abyssal plain, as submarine fanglomerates (distal part). The Upper Cretaceous rocks of Nakhlak area were thrusted over to the Ashin Formation.
     From lithological and paleontological point of view, the Triassic rocks of Nakhlak area are not correlative to other Triassic rocks of Iran.
     The only correlative rock units similar to the Triassic rocks of Nakhlak area are Aghdarband Group of northeastern Iran. The present study has shown that these rocks were adjacent to each other as well as being in the same sedimentary basin at the time the southern active margin of Turanian continental block existed.