Document Type : Original Research Paper


1 Department of Geology, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Geology, Faculty of science, University of Zanjan, Iran


Sea cows are exceptional fossil vertebrates recently discovered in the deposits of the Qom Formation. Yet, the Sirenia-bearing limestones are still poorly understood in terms of detail paleoenvironmental and micropaleontological investigations. In order to distinguish the temporal and paleoenvironmental context of the Sirenia (sea cow) bearing deposits of the Qom Formation in central Iran, three stratigraphic sections were studied in Hamedan (Ivak and Shirinsu) and Isfahan (Chahriseh) provinces. A total number of 47 thin sections were studied for micropaleontology, biozonation and carbonate microfacies analysis, as well as sedimentary environment recounstruction. Biostratigraphical investigations suggest that the Sirenia-bearing deposits are Aquitanian/Burdigalian in age, which implies restriction of sea cows remains to the Lower Miocene. We recognized nine microfacies (n=8 correspond to carbonate; n=1 correspond to siliciclastic) in the study areas. They are systematically grouped into two microfacies settings, representing inner and middle ramp environments. This is based on the facies associations and the distribution of skeletal components and rock textures.  The Sirenia-bearing limestone consists of peloid/algae bearing wackstone/packstone/floatstone. A carbonate (inner) ramp system under shallow water conditions is interpreted as the habitats of the Sirenian mammals during the Aquitanian/Burdigalian in Central Iran. This paleoenvironmental setting could be utilized for further exploration of Qom Formation deposits for discovering sea cows.


  1. Abbassi N, Domning DP, Navidi Izad N, Shakeri S (2016) Sirenia fossils from Qom Formation (Burdigalian) of the Kabudar Ahang area, Northwest Iran, Rivista Italiana Paleontologia et Stratigrafia 122: 13-24.
  2. Abyat Y, Abyat A, Abyat A (2019) Microfacies and depositional environment of Asmari formation in the Zeloi oil field, Zagros basin, south-west Iran, Carbonates and Evaporites 34: 1583-1593.
  3. Adabi MH, Kakemem U, Sadeghi A (2015) Sedimentary facies, depositional environment, and sequence stratigraphy of Oligocene–Miocene shallow water carbonate from the Rig Mountain, Zagros basin (SW Iran), Carbonates and Evaporites 31: 69-85.
  4. Adams TD, Bourgeois F (1967) Asmari biostratigraphy of Iran. Oil Operation Co., Geological Exploration Division, Report: 1074, 37p.
  5. Aghanabati A (2004) Geology of Iran, Geological Survey of Iran, Tehran, 586 p. (in Persian).
  6. Amanpour M (2018) Vertebrates paleontology, biostratigraphy and microfacies of Qom Formation at Sorkh Abad region, south-east of Hamedan. Master thesis of Zanjan university (in Persian).
  7. Amir-Shah-Karami M, Naimi M (2016) Biostratigraphy of large benthic foraminifera in Oligocene-Miocene deposits of Qom Formation at Kahak region in Urmieh-Dokhtar, Stratigraphy and sedimentary researches 36:91-108 (in Persian).
  8. Avarjani S, Mahboubi A, Moussavi-Harami R, Amiri-Bakhtiar H, Brenner RL (2015) Facies, depositional sequences, and biostratigraphy of the Oligo-Miocene Asmari Formation in Marun oilfield, North Dezful Embayment, Zagros Basin, SW Iran, Palaeoworld 24: 336-358.
  9. Babazadeh SA, Ghasemiyan S, Mosadegh H, Shakeri A (2014) Biostratigraphy and Lithostratigraphy Qom Formation from Shahanjarin Section in Garmab City, Zanjan, Stratigraphy and paleontology researches quarterly 1:31-39 (in Persian).
  10. Bajpai S, Domning DP (1997) A new dugongine Sirenian from the early Miocene of India, Journal of Vertebrate Paleontology 17: 219-228.
  11. Bajpai S, Domning DP, Das DP, Vélez-Juarbe J, Mishra VP (2010) A new fossil Sirenian (Mammalia, Dugonginae) from the Miocene of India. Neues Jahrbuch Geologie Palentologie 258: 39-50.
  12. Baratian M, Arian MA, Yazdi A (2020) Petrology and Petrogenesis of Siah Kooh Volcanic Rocks in the Eastern Alborz. Geosaberes 11: 349-363
  13. Berta A, Sumich J, Kovacs K (2006) Marine Mammals: Evolutionary Biology, Academic Press, 547 p.
  14. Bianucci G, Landini W, Varola A (2003) New records of Metaxytherium (Mammalia: Sirenia) from the late Miocene of Cisterna quarry (Apulia, southern Italy). Boll. Soc. Paleontol. Ital., 42(1-2): 59-63.
  15. Bolourchi MH, Hadjian J (1979) Geological map and explanatory text of Kabudar Ahang Quadrangle 1:250000, Geological Survey of Iran.
  16. Daneshian J, Akhlaghi M (2010) Introduction of new genus and species of benthic foraminifera of Qom Formation in Kaltakeh section, south-east of Mahneshan, Journal of Stratigraphy and Sedimentology Researches 39:71-104 (in Persian).
  17. Daneshian J, Shahrabi M, Akhlaghi M (2010) Biostartigraphy and paleoenvironment of the Qom Formation deposits at north-east of Mahneshan, Geosciences 19: 45-50 (in Persian).
  18. Domning DP, Pervesler P (2013) The Sirenian Metaxytherium (Mammalia: Dugongidae) in the Badenian (Middle Miocene) of Central Europe. Austrian Journal of Earth Sciences 105: 125-160.
  19. Dunham RJ (1962) Classifcation of carbonate rocks according to depositional texture. In: Ham WE. (Eds.) Classifcation of carbonate rocks, American Association of Petroleum Geologist Memoir 1:108-121.
  20. Eghlimi B (1999) Geological map of Hamedan quadrangle 1/100000, Geological Survey of Iran.
  21. Embry AF, Klovan JE (1971) A late Devonian reef tract on northeastern Banks Island Northwest Territories. Bulletin of Canadian Petroleum Geology 19:730-781.
  22. Flügel E (2010) Microfacies of carbonate rocks; Analysis, interpretation and application, Springer, 976 p.
  23. GhasemShirazi B, Bakhshandeh L, Yazdi A (2014) Paleoecology of Upper Cretaceous Sediments in Central Iran, Kerman (Bondar- e Bido Section) Based on Ostracods. Marine Science 4 (2): 49-57
  24. Hallock P (2015) Changing influences between life and limestones in earth history. Coral Reefs in the Anthropocene:17-42.
  25. Harzhauser M, Kroh A, Mandic O, Piller WE, Göhlich U, Reuter M, Berning B (2007) Biogeographic responses to geodynamics: a key study all around the Oligo- Miocene Tethyan Seaway. Zoologischer Anzeiger 246: 241-256.
  26. Inan S, Tasli K, Eren M, Inan N, Koç H, Zorlu K, Taga H, Zorlu K, Arslanbaş O, Demircan F (2008) First finding of Metaxytherium (sea cow) in the Miocene limestones of the Erdemli (Mersin) area (S Turkey), Turkish Geology congress Abstracts 61: 1-7.
  27. Jalali M, Sadeghi A, Adabi MH (2017) Microfacies, sedimentary environment and sequence stratigraphy of Qom Formation at Chah Yorteh Shah 1 and Mureh Kuh section (South of Tehran), Journal of Stratigraphy and Sedimentology Researches 33: 25-48 (in Persian).
  28. Jones B, Desrochers A (1992) Shallow platform carbonates. In: Walker RG, James NP, (Eds.), Facies Models Response to Sea Level Changes: 277-303.
  29. Karevan M, Mahboubi A, Vaziri-Moghaddam H, Moussavi-Harami R (2015) Sedimentary facies and sequence stratigraphy of the Qom Formation deposits, NE Delijan, NW Central Iran, Geosciences 24:237-248 (in Persian).
  30. Kordos L (1985) The evolution of the Cenozoic Sirenian on the basic of Hungarian fossil remains, Abstracts of the 8th Congress of Regional Committee of Mediterranean Neogene Stratigraphy, Symposium on European Late Cenozoic Mineral Resources: 314.
  31. Loeblich A, Tappan H (1987) Foraminiferal genera and their classification. Van Nostrand Reinhold, New York.
  32. Mirzaie Ataabadi M, Orak Z, Paknia M, Alizadeh JM, Gholamalian H, Mojib I, Mirzaie J, Yazdi M (2014) First report of marine mammal remains from the Oligo-Miocene deposits of Central Iran and Zagros basins, Proceedings of the 8th meeting of the Paleontological Society of Iran: 124-129 (in Persian).
  33. Mohammadi E, Hasanzadeh-Dastgerdi M, Ghaedi M, Dehghan R, Safari A, Vaziri Moghaddam H, Baizidi C, Vaziri M, Sdari E (2013) The Tethyan Seaway Iranian Plate Oligo-Miocene deposits (Qom Formation): distribution of Rupelian (Early Oligocene) and evaporate deposits as evidences for timing and trending of opening and closure of the Tethyan Seaway, Carbonate Evaporite 28:321-345.
  34. Mohammadi E, Safari A, Vaziri-Moghaddam H, Vaziri MR, Ghaedi M (2011) Microfacies analysis and paleoenviornmental interpretation of the Qom Formation, South of Kashan, Central Iran, Carbonate Evaporite 26:255-271.
  35. Mohammadi E, Vaziri MR, and Dastanpour M (2015) Biostratigraphy of the Nummulitids and Lepidocyclinids bearing Qom Formation based on Larger Benthic Foraminifera (Sanandaj–Sirjan fore-arc basin and Central Iran back-arc basin, Iran), Arabian Journal of Geosciences 8:403-423.
  36. Mohammadi E. Vaziri MR. and Dastanpour M. (2014) Microfacies evaluation and sedimentary environment recounstruction of the Qom formation in Sirjan area, southwest Kerman. Journal of Stratigraphy and Sedimentology Researches, 30: 35- 54 (in Persian).
  37. Nouradini M, Azami SH, Hamad M, Yazdi M, Ashouri A (2015) Foraminiferal paleoecology and paleoenvironmental reconstructions of the lower Miocene deposits of the Qom Formation in Northeastern Isfahan, Central Iran, Boletín de la Sociedad Geológica Mexicana 67:59-73.
  38. Nouradini M, Yazdi M, Ashouri A (2014) Systematic notes on Burdigalian Echinoids from the Qom Formation in the Bagher Abad area, Central Iran, Geopersia 4:155-167.
  39. Pomar L (2001) Types of carbonate platforms, a genetic approach, Basin Research 13:313-334.
  40. Poorbehzadi K, Yazdi A, Sharifi Teshnizi E, Dabiri R (2019) Investigating of Geotechnical Parameters of Alluvial Foundation in Zaram-Rud Dam Site, North Iran. International Journal of Mining Engineering and Technology 1(1): 33-34.
  41. Popov SV, Rögl S, Rozanov AY, Steininger FF, Shcherba IG and Kovac M (2004) Lithological-Paleogeographic maps of the Paratethys. Courier Forschungsinstitüt Senckenberg 250:1-46.
  42. Rabbani J, Mirzaie Ataabadi M, Shaahsavari E (2020) Microfacies, sedimentary environmental model and relative sea level change of marly strata of the Qom Formation in Zarrin-Abad section, South of Zanjan. Journal of Stratigraphy and Sedimentology Researches 36:115-134 (in Persian).
  43. Rafiee P, Baghbani D (2008) Biostratigraphy of the Qom Formation in Shahnajrin region, south-east of Razan. Proceedings of the 2nd meeting of the Paleontological society of Iran, p. 70-73 (in Persian).
  44. Rahimzadeh F (1994) Treatise on the Geology of Iran; Oligocene, Miocene, Pliocene. Geological Survey of Iran, 311 p. (in Persian).
  45. Reuter M, Piller WE, Harzhauser M, Mandic O, Berning B, Rögl F, Kroh A, Aubry MP, Wielandt-Schuster U, Hamedani A (2009) The Oligo-Miocene Qom Formation (Iran): evidence for an early Burdigalian restriction of the Tethyan Seaway and closure of its Iranian gateways. International Journal of Earth Science 98: 627-650.
  46. Reza SM, Barry JC, Meyer GE, Martin L (1984) Preliminary report on the geology and vertebrate fauna of the Miocene Manchar Formation, Sind, Pakistan, Journal of Vertebrate Paleontology 4: 584-599.
  47. Robbins LL, Knorr PO, Wynn JG, Hallock P (2016) Interpreting the role of pH on stable isotopes in large benthic foraminifera, ICES Journal of Marine Science 74: 955-964.
  48. Romero J, Caus E, Rossel J (2002) A model for the palaeoenvironmental distribution of larger foraminifera based on Late Middle Eocene deposits on the margin of the south Pyrenean basin (SE Spain), Palaeogeography, Palaeoclimatology, Palaeoecology 179: 43-56.
  49. Sadeghi R, Vaziri-Moghaddam H, Taheri A (2009) Biostratigraphy and paleoecology of the Oligo-Miocene succession in Fars and Khuzestan areas (Zagros Basin, SW Iran), Historical Biology 21: 17-31.
  50. Safari A, Ameri H, Vaziri MR, Mohammadi E (2013) Micofacies and sedimentary environment of the Qom Formation at Varakan region (South-West of Kerman) fore-arc basin of Sanandaj- Sirjan, Paleontology 1: 187-204, (in Persian).
  51. Seddighi M, Vaziri-Moghaddam H, Taheri A, Ghabeishavi A (2011) Depositional environment and constraining factors on the facies architecture of the Qom Formation, Central Basin, Iran, Historical Biology 24:91-100.
  52. Sorbi S (2008) New record of Metaxytherium (Mammalia, Sirenia) from the lower Miocene of Manosque (Provence, France), Geodiversitas 30: 433-444.
  53. Stephenson CM, Hallock P, Kelmo F (2015) Foraminiferal assemblage indices: a comparison of sediment and reef rubble samples from Conch Reef, Florida, USA, Ecological Indicators 48: 1-7.
  54. Thewissen JGM, Bajpai S (2009) A new Miocene Sirenian from Kutch, India, Acta Palaeontologia Polonica 54: 7-13.
  55. Wilson JL (1975) Carbonate facies in geological history, Springer.
  56. Wynd JG (1965) Biofacies of the Iranian Oil Consortium Agreement area, Report No. 1082.
  57. Yazdi A, Shahhosini E, Dabiri R, Abedzadeh H (2019) Magmatic differentiation evidences and source characteristics using mineral chemistry in the Torud intrusion (Northern Iran). Revista Geoaraguaia 9(2): 1-21.
  58. Yazdi M, Shirazi MP, Rahiminejad AH, Motavalipoor R (2012) Paleobathymetry and paleoecology of colonial corals from the Oligocene-Early Miocene Qom Formation (Dizlu area, central Iran), Carbonate Evaporite 27:395– 405.
  59. Yazdi-Moghadam M (2011) Early Oligocene Larger Foraminiferal Biostratigraphy of the Qom Formation, South of Urmieh (NW Iran), Turkish Journal of Earth Science 20:847- 856.
  60. Yazdi-Moghadam M, Sadeghi A, Adabi MH, Tahmasbi A (2018) Foraminiferal biostratigraphy of the lower Miocene Hamzian and Arashtanab sections (NW Iran), northern margin of the Tethyan Seaway, Geobios 5:231-246.
  61. Zahedi M, Amidi M (1978) Geological map of the Isfahan quadrangle 1/250000, Geological Survey of Iran.