OICC Press Iranian Journal of Earth Sciences 2228-785X 16 3 2024 09 27 Systematic descriptions of alveolinids from the Ilerdian-Cuisian (Ypresian) of Hormak conglomerates of Ghargharook section from north Zahedan, East Iran Belt 1 18 10.57647/j.ijes.2024.1603.17 EN Hamed Yarahmadzahi Department of Geology, Earth Sciences Research Center, Zahedan Branch, Islamic Azad University, Zahedan, Iran https://orcid.org/0000-0003-2260-3489 Derya Sinano˘glu Department of Petroleum and Natural Gas Engineering, Batman University, Batman, Turkey https://orcid.org/0000-0002-9307-7810 Journal Article 2024 09 27 Alveolinids benthic foraminifera, are known as significant biostratigraphic markers, commonly occur in shallow water carbonates of Eocene deposits from Tethyan regions. Twenty-nine species and three subspecies of the genus Alveolina are described from carbonate pebbles of the Hormak conglomerates (Ghargharook section) in northeastern Zahedan (Eastern Iran Belt). The Ilerdian and Cuisian chronstratigraphic units of the study area are characterized by perfectly preserved specimens of Alveolina species such as A. archiaci adamsi, A. aramaea, A. canavari, A. corbarica, A. cremae, A. dedolia taneri, A. aff. di-stefanoi, A. ellipsoidalis, A. erki, A. aff. frumentiformis, A. gambaensis, A. globosa, A. globula, A. aff. guidonis, A. haymanaensis, A. himalayensis, A. kayserensis, A. minuta, A. moussoulensis, A. oblonga, A. parva, A. pisiformis, A. reicheli, A. rotundata kazancii, A. ruetimeyeri, A. sakaryaensis, A. schwageri, A. subpyrenaica and A. aff. tumida. These species are found throughout many shallow-water successions of the Tethyan region during the Lower Eocene (subzones 6−12). Calcareous pebbles containing Alveolina are originated from the northern parts of the mountains of Eastern Iran, mainly Safid Abeh, Bandan, Nehbandan and Birjand areas. These pebbles were parts of the local Zebro, Debil, and Palang formations.