دانشگاه فردوسی مشهد رخساره‌های رسوبی 2008-787X 11 1 2018 08 23 The first report of the Eocene annelid worms (Polychaeta) of Sarakeh syncline (Soh area - northwest of Isfahan - Central Iran) اولین گزارش از لوله‌های زیستی کرم‌های حلقوی پلی‌کیت (پرتاران) ائوسن از ناودیس سراکه (منطقه سُه، شمال غرب اصفهان ـ ایران مرکزی) 1 14 29308 10.22067/sed.facies.v11i1.59559 FA علی بهرامی دانشگاه اصفهان مهدی یزدی دانشگاه اصفهان صفوره صدری دانشگاه اصفهان مرجان خداوردی حسن وند دانشگاه اصفهان Journal Article 2016 10 16 Introduction Generally, the rotularians have high frequency in bioturbated environment in moderate to high water energy. Rotularians were also cemented to the substrate during their earliest growth stage, but they became detached shortly after the formation of first whorls. Tube records of rotularia are known from Mesozoic (Late Jurassic) to Early Tertiary sediments, becoming very common during the Cretaceous and Eocene and also has a global distribution. The fossil species Rotularia spirulaea has become extinct close to the end of Eocene - Oligocene time (Howell, 1962; Fauchald & Jumars, 1979; Macellari, 1984; Ruppert et al., 2004; Hove & Kupriyanova, 2009; Sørensen & Surlyk, 2010).  Geological settings Outcrops in the Soh area include the widely distributed Paleozoic (Zahedi, 1973; Adhamian, 2003; Wendt et al., 2005; Ghobadipour et al., 2013; Bahrami et al., 2015) and Mesozoic deposits (Mannani & Yazdi, 2009; Yazdi et al., 2010), as well as the Paleocene to Oligo-Miocene deposits, the youngest marine sequences, which start with terrigenous red to white sequence of Paleocene conglomerate and sandstone, continued by Eocene fossiliferous carbonates and marls. The Sabkha deposits at the top of the Oligo-Miocene Qom Formation terminates the depositional cycle of the marine sequence. A thick Eocene succession is widely exposed in the studied region (Sadri, 2011; Janssen et al., 2013). The studied section is located near the village of Soh-in Sarakeh Syncline (90 km Northwest of Isfahan)  and  is accessible by a 35 km unpaved road off the Isfahan - Tehran highway. The section is situated on the right side of a seasonal river valley that is observable from a distance in the plain. Coordinates for the fossil locality are: N 33º28´36˝, E 51º27´6˝. Structurally, the locality belongs to the Central Iran microplate, which is restricted by the NW-SE Sanandaj- Sirjan metamorphic belt to the West, and by the Great Kavir fault to the East. Discussion The studied section is about 354 meters thick. Based on field observation, sedimentological features and fossil contents, 11 lithological packages are discriminated. 18 meters of Marl at the base of the Eocene (Package 1) contains rich with high diversity of marine faunas e.g. : Benthic foraminifers, Crustacean remains, bivalves, Gastropods and Polychaet tube worms (Rotularia spirulaea). Fossil rotularia with accompanying fauna: crab remains, gastropods, bivalves and benthic foraminifers are indicatives of warm shallow marine paleoenvironments during the deposition of the studied interval. Specimens are deposited in the Department of Geology, Faculty of Science, University of Isfahan, 81746, Iran, under acronym EUIC. Acknowledgment This study undertaken at the Department of Geology, Faculty of Science, University of Isfahan. The financial supports by the Vice Chancellor for Research and Technology, University of Isfahan highly appreciated. Keywords: Eocene; Annelid worm; Sarakeh synclinal; Rotularia; Serpulid. References Fauchald, K., 1977. The Polychaete worms. Definitions and keys to the orders, families and genera. Natural History Museum of  Los Angeles County, Science Series, 28: 1-190. Fauchald, K., & Jumars, P.A., 1979. The diet of worms: a study of polychaete feeding guilds. Oceanography and Marine Biology Annual Review, 17: 193-284. Hove, H.A., ten & Kupriyanova, E.K., 2009. Taxonomy of Serpulidae (Annelida, Polychaeta): the state of affairs. Zootaxa, 2036: 1-126. Howell, B.F., 1962. Worms. In: Moore, R.C., (ed.), Treatise on Invertebrate Paleontology: Part W Miscellanea,(Geological Society of America and University of Kansas Press: Lawrence), W144-W177. Janssen, A.W., Jagt, J.W.M., Yazdi, M., Bahrami, A., & Sadri, S., 2013. Early-middle Eocene faunal assemblages from the Soh Area, north-central Iran, Introduction and pteropods (Mollusca, Gastropoda, Thecosomate). Cainozoic Research, 10 (1-2): 23-34. Khodaverdi Hassan-vand, M., Bahrami, A., Yazdi, M., Osso, A., Safari, A., Martinez, J.L., & Vega, F.J., 2016. Occurrence of Retrocypoda almelai Via Boada, 1959 (Decapoda: Retroplumidae) in the Eocene of Central Iran. Paleontología Mexicana, 5 (1): 21-31. Macellari, C.E., 1984. Revision of Serpulids of the genus Rotularia (Annelida) at Seymour Island (Antarctic Peninsula) and their value in stratigraphy. Journal of Paleontology, 58 (4): 1098-1116. Mannani, M., & Yazdi, M., 2009. Late Triassic and early Cretaceous sedimentary sequences of northern Isfahan Province (central Iran): stratigraphy and paleoenvironment: Boletín de la Sociedad Geológica Mexicana, 62: 207-211. Ruppert, E.E., Fox, R.S., & Barnes, R.D., 2004. Invertebrate Zoology, a Functional Evolutionary Approach. Thomson- Brooks/Cole, Belmont, USA, 963 p. Sørensen, A.M., & Surlyk, F., 2010. Palaeoecology of tube-dwelling polychaetes on a Late Cretaceous rocky shore, IvöKlack (Skåne, Peninsula) and their value in stratigraphy. Cretaceous Research, 31: 553-566. Yazdi, M., Bahrami, A., & Vega, J., 2010. Addition to Albian (Cretaceous) Crustacea from Iran. Boletín de la sociedad geológica Mexicana, 62: 207- 211. Zahedi, M., 1973. Etude geologique de La region de Soh (W de Iran central). Geological survey of Iran, 197 p. مطالعه نهشته‌های کربناته و مارنی دارای بقایای لوله‌های زیستی کرم‌های حلقوی پلی‌کیت در منطقه سُه اصفهان (ناودیس سراکه) به شناسایی گونه Rotularia spirulaea از خانواده کرم‌های سرپولید منجر گردید. به طورکلی Rotularia در محیط‌هایی که به هم ریختگی لایه‌ها توسط موجودات زنده زیاد باشد و در محیط‌های با انرژی متوسط تا بالا به طور فراوان یافت می‌شود. بسیاری ازکرم‌های Rotularia قسمت یا تمامی طول عمر خود را در لوله‌های آهکی یا سیمانی ترشح شده گذرانیده‌اند. این کرم حلقوی اغلب از زمان ژوراسیک تا پالئوژن در دریاهای کم‌عمق (ائوسن) وجود داشته و در مرز ائوسن ـ الیگوسن منقرض شده است. کرم‌های Rotularia به همراه بقایایی از قطعات خرچنگ، شکم‌پا و روزن‌داران کف‌زی گویای شرایط دریایی کم‌عمق در زمان تشکیل نهشته‌های مورد مطالعه بوده است. https://jearth.um.ac.ir/article_29308_229b80a4b334bbda34ec0d063f11c699.pdf