Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia ARTEM KOUCHINSKY, STEFAN BENGTSON, ED LANDING, MICHAEL STEINER, MICHAEL VENDRASCO, and KAREN ZIEGLER Kouchinsky, A., Bengtson, S., Landing, E., Steiner, M., Vendrasco, M., and Ziegler, K. 2017. Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia. Acta Palaeontologica Polonica 62 (2): 311‒440. Assemblages of mineralized skeletal fossils are described from limestone rocks of the lower Cambrian Nemakit-Daldyn, Medvezhya, Kugda-Yuryakh, Manykay, and lower Emyaksin formations exposed on the western and eastern flanks of the Anabar Uplift of the northern Siberian Platform. The skeletal fossil assemblages consist mainly of anabaritids, molluscs, and hyoliths, and also contain other taxa such as Blastulospongia, Chancelloria, Fomitchella, Hyolithellus, Platysolenites, Protohertzina, and Tianzhushanella. The first tianzhushanellids from Siberia, including Tianzhushanella tolli sp. nov., are described. The morphological variation of Protohertzina anabarica and Anabarites trisulcatus from their type locality is documented. Prominent longitudinal keels in the anabaritid Selindeochrea tripartita are demon- strated. Among the earliest molluscs from the Nemakit-Daldyn Formation, Purella and Yunnanopleura are interpreted as shelly parts of the same species. Fibrous microstructure of the outer layer and a wrinkled inner layer of mineralised cuticle in the organophosphatic sclerites of Fomitchella are reported. A siliceous composition of the globular fossil Blastulospongia is reported herein and a possible protistan affinity similar to Platysolenites is discussed. New carbon isotope data facilitate correlation both across the Anabar Uplift and with the Terreneuvian Series of the IUGS chronos- tratigraphical scheme for the Cambrian System. The base of Cambrian Stage 2 is provisionally placed herein within the Fortunian‒Cambrian Stage 2 transitional interval bracketed by the lowest appearance of Watsonella crosbyi and by a slightly higher horizon at the peak of carbon isotope excursion Iʹ from western flank of the Anabar Uplift. Correlation 13 across the Siberian Platform of the fossiliferous Medvezhya and lower Emyaksin formations showing δ Ccarb excur- sion Iʹ with the upper Sukharikha Formation containing excursion 5p and upper Ust’-Yudoma Formation containing excursion I is supported herein. Key words: Mollusca, stratigraphy, carbon isotopes, Cambrian, Terreneuvian, Russia, Siberia, Anabar. Artem Kouchinsky [[email protected]] and Stefan Bengtson [[email protected]], Department of Palaeo- biology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden. Ed Landing [[email protected]], New York State Museum, 222 Madison Ave, Albany, NY 12230, USA. Michael Steiner [[email protected]], Freie Universität Berlin, Malteserstrasse 74-100, Haus C Raum C.021, D-12249 Berlin, Germany. Michael Vendrasco [[email protected]], Department of Geology, Pasadena City College, 1570 E Colorado Blvd, Pasadena, CA 91106, USA. Karen Ziegler [[email protected]], Institute of Meteoritics, 1 University of New Mexico, Albuquerque, NM 87131- 0001, USA. Received 29 June 2016, accepted 28 February 2017, available online 31 May 2017. Copyright © 2017 A. Kouchinsky et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unre- stricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Scale of Russia (Khomentovsky and Karlova 1993, 2005; Introduction Rozanov et al. 2008) and assigned to the Vendian System. According to the Interdepartmental Stratigraphic Commit- The upper or the entire Nemakit-Daldynian is correlated tee of Russia (Zhamoida and Petrov 2008), the base of the with the Fortunian Stage of the Terreneuvian Series (e.g., Cambrian System on the Siberian Platform coincides with the Khomentovsky and Karlova 2005; Khomentovsky 2008; base of the Tommotian Stage. The underlying dolostone-dom- Zhamoida and Petrov 2008; Rogov et al. 2015). The latter are inated strata on the Siberian Platform are commonly referred the lowest stage and series of the IUGS chronostratigraphical to the Nemakit-Daldynian Stage of the General Stratigraphic scheme for the Cambrian System, whereas informal Cambrian Acta Palaeontol. Pol. 62 (2): 311‒440, 2017 https://doi.org/10.4202/app.00289.2016 312 ACTA PALAEONTOLOGICA POLONICA 62 (2), 2017 Stage 2 is upper Terreneuvian (e.g., Landing et al. 2007, 2013; Platform facilitate comparison with Terreneuvian faunas of Peng and Babcock 2011). Although the Nemakit-Daldynian western Mongolia, Kazakhstan, Laurentia, Bal tica, Ava lo- Stage is traditionally and officially used in Russia, neither the nia, and Gondwanan regions as South China, India, Iran, Nemakit-Daldynian nor the synonymous Manykayan Stage and France. This paper continues the reports by Guba nov et can be formally used as regional chronostratigraphic units, al. (2004b) and Kouchinsky et al. (2011, 2015a, b; SOM 5: as “Nemakit-Daldyn” and “Manykay,” by the international figs. 9–17, Suplementary Online Material available at http:// rules of stratigraphic nomenclature, are preoccupied and were app.pan.pl/SOM/app62-Kouchinsky_etal_SOM.pdf) of fos- earlier used as lithostratigraphic names (e.g., Salvador 1994). sil assemblages known from younger beds on the eastern Historically, “Nemakit-Daldyn” and “Manykay” have flank of the Anabar Uplift. been applied to two time-equivalent lithostratigraphic units (formations) on the Anabar Uplift. The Nemakit-Daldyn Institutional abbreviations.—SMNH (Mo, X), Swedish Formation was defined by Savitsky (1962) at the mouth Museum of Natural History, Stockholm, Sweden (molluscs, of the Nemakit-Daldyn River, a tributary of the Eriechka other fossils). River, and traced in the north-western and northern flanks Other abbreviations.—SSF, small shelly fossils. of the Anabar Uplift between the Kotuj and Popigaj riv- ers. The Manykay Formation was defined by Boris G. Lopatin and collegues in 1958–1959 (see Demokidov and Lazarenko 1964) along the middle course of the Malaya Material and methods Kuonamka River (near the mouth of the Manykay Creek) on the south-eastern flank of the Anabar Uplift. The The material described herein was collected during field- Nemakit-Daldyn and Manykay formations are respec- works in the Anabar Uplift of Siberia, Russia. The collections tively overlain by the Medvezhya and Emyaksin forma- were made by AK and SB from the Manykay and Emyaksin tions. The Medvezhya Formation on the western flank of the formations along the Bol’shaya Kuonamka River in 1996 and Anabar Uplift was first defined in 1959–1960 by Vladimir from the Nemakit-Daldyn, Medvezhya, and Kugda-Yuryakh E. Savitsky (Egorova and Savitsky 1969) along the upper formations along the Kotuj River in 1992, 2007 (by AK) and reaches of the Medvezhya River, upstream of the mouth of 2008 (by Vladimir Pavlov) (Figs. 1–4; SOM 5). the Daldyn River. The Emyaksin Formation was named by Section 1 herein (locality M410 in Rozanov et al. 1969; Mikhail N. Zlobin (see Demokidov 1956, 1958) at the mouth locality 3 in Meshkova et al. 1976) is located at 70°08.5’ N, of the Emyaksin-Yurege River, a tributary of the Malaya 114°00’ E (Figs. 1 and 4; SOM 5: figs. 1, 2; see also Landing Kuonamka River, and traced along the southeastern, east- and Kouchinsky 2016). It crops out on the left bank of the ern, and northeastern flanks of the Anabar Uplift. Kotuj River, upstream from the mouth of Ary-Mas-Yuryakh The name Kugda-Yuryakh Formation was coined by the Creek. The lowermost sampled part of section 1 belongs geologists of the Krasnoyarsk Geological Survey (“Krasno- to the uppermost Nemakit-Daldyn Formation (thrombolitic yarskgeologiya”) in 1979 (see Dyatlova et al. 1990). Minaeva boundstone of the Koril Member; Kaufman et al. 1996), (1985, 1991) mentioned the Kugda-Yuryakh Formation as the which is overlain above the sequence boundary by lime- “Serotsvet [grey-colored] Member” or Serotsvet Formation. stone beds of the Medvezhya Formation grading upwards Missarzhevsky (1989: 66, fig. 15) placed the “Kugda beds” into grey limestone with oolites attributable to the Kugda- between the top of the Medvezhya Formation and the bot- Yuryakh Formation (e.g., Dyatlova et al. 1990; Fig. 4). tom of the overlying “Kyndyn beds”. Kaufman et al. (1996: Section 2 (locality M419 in Rozanov et al. 1969; section 515) assigned the “Kugda beds” to the “Kyndyn Formation”, E8 in Val’kov 1975) is situated at 70°37’ N; 103°31.5’ E, but noted that their lower and upper boundaries are region- along the right bank of the Kotujkan River, ca. 2.5 km ally diachronous and problematic for lithostratigraphic cor- upstream its mouth (Fig. 1; SOM 5: fig. 3). The section relation alone. embraces the Nemakit-Daldyn Formation (mainly lime- This report provides additional information on the re- stone with minor addition of dolostone layers and interbed- gional and global chronostratigraphy of the lowest part of ded siliciclastics in the lower part) separated by sequence the Cambrian System, or the Terreneuvian Series. The early boundaries from the underlying Staraya Rechka Formation skeletal fossils illustrated and discussed herein along with (Ediacaran, mainly stromatolitic dolostone in the upper part) the carbon isotope chemostratigraphy from the western and and the overlying variegated lime mudstone and wackestone