Dinoflagellate cysts from the Upper Triassic (Rhaetian) strata of the Tabas Block, East - Central Iran

Document Type : Research Paper


1 Exploration Directorate of National Iranian Oil Company, Tehran, Iran

2 Department of Geology, Faculty of Sciences, University of Tehran, Tehran, Iran



Rhaetian strata from the Nayband Formation of the Tabas block, East- Central Iran, were studied palynologically. The material
examined contained moderately diverse and well-preserved dinoflagellate cyst assemblages which lead to the identification of
Rhaetogonyaulax rhaetica Zone. The assigned age of this dinozone (Rhaetian) is justified by plant fossils such as Equisetites
arenaceus, Scytophyllum persicum, Pterophyllum bavieri, Pterophyllum aequale and Nilssoniopteris musafolia recorded from these
strata. The dinoflagellate cysts show close similarities with assemblages reported from Australia, Northwest Europe, Arctic Canada
and Northern Iran. Furthermore, the associated marine palynomorphs (dinoflagellate cysts), accompanied by spores grain indicate a
nearshore depositional environment for the Late Triassic (Rhaetian) deposits in Tabas Block of Iran.


Article Title [فارسی]

داینوسیستهای تریاس فوقانی (رتین) در بلوک طبس، شرق ایران مرکزی

Authors [فارسی]

  • حسین صباغیان 1
  • ابراهیم قاسمی نژاد 2
  • محمد رضا آریانسب 1
1 کارشناس مدیریت اکتشاف، تهران
2 دانشیار زمین شناسی دانشگاه تهران
Abstract [فارسی]

رسوبات به سن رتین مربوط به سازند نایبند در بلوک طبس، شرق ایران مرکزی مورد مطالعه پالینولوژی قرار گرفت. در بررسی نمونه ها، مشخص شد که داینوسیستها در این نمونه ها از تنوع و حفظ شدگی خوبی برخوردارند که منجر به شناسایی بایوزون Rhaetogonyaulax rhaetica در این رسوبات شد. سن بدست آمده برمبنای این بایوزون(رتین) در تطابق کامل با سن بدست آمده براساس فسیل های گیاهی نظیر Equisetites arenaceus, Scytophyllum persicum, Pterophyllum bavieri, Pterophyllum aequale و Nilssoniopteris musafolia می باشد که در این رسوبات گزارش شده اند. اجتماع داینوفلاژله های شناسایی شده شباهت زیادی با اجتماع داینوفلاژله های گزارش شده از استرالیا، شمال غرب اروپا، آرکتیک کانادا و شمال ایران دارند. همچنین همراهی پالینومورفهای خشکی(گرده و هاگ) با پالینومورفهای دریایی(داینوفلاژله) نشانگر محیط رسوبی نزدیک ساحل در رسوبات تریاس فوقانی بلوک طبس می باشد.

Keywords [فارسی]

  • تریاس فوقانی
  • داینوسیست ها
  • پالئوبیوژئوگرافی
  • بلوک طبس
  • ایران
Achilles, H., Kaiser, H., Schweitzer, H.J., 1984. Die Rato-Jurassischen Floren des Iran und Afganistan. 7. Die Mikroflora
der Obertriadisch-Jurassischen Ablagerungen des Alborz Gebirges (Nord-Iran). Palaeontographica Abteilung B, 194:
Arjang, B., 1975. Die Rato-Jurassischen Floren des Iran und Afganistan. 1. Die Mikroflora der Rato-Jurassischen
Ablagerungen des Kermaner Beckens (Zentral Iran). Palaeontographica Abteilung B, 152: 85-148.
Bragin, N., Jahanbakhsh, F., Golubev, S.A., Badovnikov, G., 1976. Stratigraphy of the Triassic- Jurassic coal-bearing
deposits of Alborz. Unpublished technical report, National Iranian Steel corporation. pp. 1-51.
Bragin, Yu.N., Golubev, S.A., Polianski, B.V., 1981. Paleogeography of major accumulation stages of Lower Mesozoic
coal deposit in Iran. Litology and Mineral Resources. 16: 50-59.
Bronnimann, P., Zaninetii, L., Bozorgna, F., Dashti, G.R., Moshtaghian, A., 1971. Lithostratigraphy and foraminifera of
the Upper Triassic Nayband Formation, lran. Revue de Micropaleontology. 14: 7-16.
Bucefalo Palliani, R., Buratti, N., 2006. High diversity dinoflagellate cyst assemblages from the Late Triassic of southern
England: new information on early dinoflagellate evolution and palaeogeography. Lethaia. 39: 305-312
Bujak, J.P., Fisher, M.J., 1976. Dinoflagellate cysts from the upper Triassic of Arctic Canada. Micropaleontology 22 (1):
Cirilli, S., Buratti, N., Senowbari-Daryan, B., Fürsich, F., 2005. Stratigraphy and palynology of the Upper Triassic
Nayband Formation of East-Central Iran, Rivista Italiana di Paleontologia e Stratigraphia. 111: 259-270.
Douglas, J.A., 1929. A marine Triassic fauna from eastern Persia. Quarterly Journal of the Geological Society, London
85, 625-650.
Fürsich, F., Hautmann, M., Senowbari-Daryan, B., Seyed-Emami, K., 2005. TheUpper Triassic Nayband and Darkuh
formations of East-Central Iran: Stratigraphy, Facies patterns and biota of extensional basins on accreted terrane.
Beringeria. 35: 53-133.
Ghasemi-Nejad, E., Agha-Nabati, A., Dabiri, O., 2004. Late Triassic dinoflagellate cysts from the base of the Shemshak 
Group in north of Alborz Mountains, Iran. Review of Palaeobotany and Palynology. 132: 207-217.
Ghasemi-Nejad, E., Sabbaghiyan, H., Mosaddegh, H., 2012. Palaeobiogeographic implications of late Bajocian–late
Callovian (Middle Jurassic) dinoflagellate cysts from the Central Alborz Mountains, northern Iran, Journal of Asian
Earth Sciences. 43: 1-10.
Haq, B.U., Hardenbol, J., Vail, P.R., 1987. Chronology of fluctuating sea levels since the Triassic. Science. 235: 1156 -
Helby, R., Morgan, R., Partridge, A.D., 1987. A palynological zonation of the Australian Mesozoic. Memoir of the
Association of Australasian Palaeontologists. 4: 1-94.
Jalali-Fard, M., Bani-Asadi, M.R., Nazemi, M., 2011. Biostratigraphy of the Nayband formation in Parvadeh area based
plant fossil. 15th symposium of geological society of Iran.Tarbiat Moalem University, Tehran, 303 p. (in Persian).
Kluyver, H.M., Tired, R., Chance, P.N., Johns, G.W., Meixncr, H. M., 1983a. Explanatory text of the Naybandan
Quadrangle Map 1: 250,000. Geological Survey of Iran, Tehran, Quadrangle, 8: 1-143.
Kluyver, H.M., Tired, R., Chance, P.N., Johns, G.W., Meixncr, H. M., 1983b. Explanatory text of the Naybandan
Quadrangle Map 1 : 250,000. Geological Survey of Iran, Tehran, Quadrangle. 9: 1-175.
Mannani, M., Yazdi, M, 2009. Late Triassic and Early Cretaceous sedimentary sequences of the northern Isfahan
Province (Central Iran): stratigraphy and paleoenvironments. Boletin de la Sociedad Geologica Mexicana. 61: 367-374.
Nicoll, R.S., Foster, C.B., 1994. Late Triassic conodont and palynomorph biostratigraphy and conodont thermal
maturation, North West Shelf Australia. Journal of Australian Geology & Geophysics. 15: 101-118.
Nützel, A., Senowbari-Daryan, B., 1999. Gastropods from the Late Triassic (Norian-Rhaetian) Nayband Formation of
Central Iran, Beringeria, 23: 93-132.
Poulsen, N.E., Riding, J.B., 2003. The Jurassic dinoflagellate cyst zonation of subboreal Northwest Europe. Geological
Survey of Denmark and Greenland Bulletin. 1: 115–144.
Powell, A.J., 1992. Dinoflagellate cysts of the Triassic system. In: Powell, A.J. (Ed.), A stratigraphic index of
dinoflagellate cysts, Chapman & Hall, London. pp. 1-6.
Senowbari- Daryan, B., 1996. Upper Triassic reefs and reef communities of Iran.In: Reitner, J., Neuweiler, F., Gunkel, F.
(Eds.), Global and Regional Controls on Biogenic Sedimentation. Gottinger Arbeiten Geologie und Paläontologie Sb2.
Seyed-Emami, K., 2003. Triassic in Iran. Facies. 48: 91–106.
Stöcklin, J., 1961. Lagunäre Formationen und Salzdome in Ostiran. Eclogae Geological Helvetiae 54: 1-27.
Takin, M., 1972. Iranian geology and continental drift in the Middle East. Nature. 235: 147–150.
Traverse, A., 2007. Paleopalynology, Second edition. Springer, Dordrecht, The Netherlands. 813 p.
Vaez-Javadi, F., 2012. Biostratigraphy of the Nayband Formation in Parvadeh mine based plant fossil. Journal of
sedimentology and stratigraphy researchs. 1: 113-143 (in Persian).
Wilmsen, M., Fürsich, F.T., Seyed-Emami, K., Majidifard, M.R., 2009. An overview of the stratigraphy and facies
development of the Jurassic System on the Tabas Block, east-central Iran. Geological Society London. Special
Publication. 312: 323–343.
Woollam, R., Riding, J.B., 1983. Dinoflagellate cyst zonation of the English Jurassic. Institute of Geological Sciences
Report. 83(2): 42 p.