Introduction and preliminary study of shell beds of the Late Cretaceous marine deposits in the western part of Makran (southeastern Kahnuj and Kerman)

In comparison with other geological zones of Iran, the Makran geological zone has been studied less. This study aims to introduce and study the Late Cretaceous fossiliferous successions (part of the Chah-Mirak Unit), in the southeastern Kahnuj (the northwestern part of the Iranian Makran geological zone) to draw the geologists’ attention to the area. Given the note that most of the rock units in the region are non-sedimentary (ophiolitic) complexes or Quaternary continental sediments, every fossil evidence is of great value for investigating and reconstructing the paleo-environmental condition of the region. Lithologically, the studied successions mainly consist of tuffaceous limestones, which were deposited after the reduction of pyroclastic material to the basin; its lower and upper contacts are composed of volcanic rocks. The studied successions present different fossil groups such as abundant gastropods, corals, algae, bivalves, and foraminifera. The gastropod-rich sequences and younger marine layers are Cenomanian and Cenomanian-early Santonian in age, respectively. The shallow marine lagoonal environment (accompanied by mollusks, especially abundant gastropods), and slightly deeper settings containing coral and algae, are suggested for the deposition of these successions. Further studies are necessary for a more detailed examination of the fossil groups.