Integrated palaeontological and sedimentological study of the Upper Ordovician Vormsi Stage in the Lelle drill core section, Central Estonia, revealed an association of shelly fauna containing the endemic saukrodictyid brachiopod Hulterstadia cor (Wiman), which is otherwise known only from erratic boulders close to Hulterstad in the southeastern area of the Island of Öland, Sweden. In the Lelle core this fauna occurs in the uppermost Fungochitina spinifera chitinozoan Biozone of mid-Vormsi age. Cyclic changes in the content of siliciclastic material in the carbonate section, and in the predominance of shallower- and deeper-water scolecodonts in the interval of the distribution range of H. cor, suggest sea-level oscillations during mid-Vormsi time. Upper Vormsi strata, corresponding to the Tanuchitina bergstroemi chitinozoan Biozone, including the Acanthochitina barbata Subzone, are characterized by common occurrence of sponge remains. Lithologies of the uppermost part of the Lelle section indicate sedimentation in channel environments. Taxonomic composition of the macrofauna in the core differs considerably from that of North Estonia, but has some similarity with the deeper-water Ashgill faunas in other regions (e.g. Fosse Formation of Belgium and Portrane Limestone of Ireland). The Estonian specimens of Hulterstadia cor are described.
Botting, J. P. 2005. Exceptionally well-preserved Middle Ordovician sponges from the Llandegley rocks Lagerstätte, Wales. Palaeontology, 48, 577–617.
doi:10.1111/j.1475-4983.2005.00470.x
Cocks, L. R. M. & Rong, J.-Y. 1988. A review of the Late Ordovician Foliomena brachiopod fauna with new data from China, Wales, and Poland. Palaeontology, 31, 53–67.
Flodén, T., Puura, V., Söderberg, P., Tuuling, I. & Suuroja, K. 1994. The Ordovician–Silurian transition beds in the seafloor between Gotland and Hiiumaa islands, Baltic Proper. Proceedings of the Estonian Academy of Sciences, Geology, 43, 1–17.
Fortey, R. A., Harper, D. A. T., Ingham, J. K., Owen, A. W. & Rushton, A. W. A. 1995. A revision of Ordovician series and stages from the historical type area. Geological Magazine,132, 15–30.
Harper, D. A. T. 1980. The brachiopod Foliomena fauna in the upper Ordovician Ballyvorgal Group of Slieve Bernagh, County Clare. Journal of Earth Sciences of the Royal Dublin Society, 2, 189–192.
Harper, D. A. T. 2000. Dalmanellinae. In Treatise on Invertebrate Paleontology, Pt. H: Brachiopoda Revised, Vol. 3: Linguliformea, Craniiformea, and Rhynchonelliformea (part) (Kaesler, R. L., ed.), pp. 782–844. Boulder, Colorado.
Harper, D. A. T., Rong, J.-Y. & Zhan, R.-B. 1999. Late Ordovician development of deep-water brachiopod faunas. Acta Universitatis Carolinae, Geologica, 43, 351–353.
Harris, M. T., Sheehan, P. M., Ainsaar, L., Hints, L., Männik, P., Nõlvak, J. & Rubel, M. 2004. Upper Ordovician sequences of Western Estonia. PALAEO,210, 134–148.
Hints, L. & Meidla, T. 1997. Vormsi Stage. In Geology and Mineral Resources of Estonia (Raukas, A. & Teedumäe, A., comps & eds), pp. 81–82. Estonian Academy Publishers, Tallinn.
Hints, L., Oraspõld, A. & Nõlvak, J. 2005. The Pirgu Regional Stage (Upper Ordovician) in the East Baltic: lithostratigraphy, biozonation and correlation. Proceedings of the Estonian Academy of Sciences, Geology, 54, 225–259.
Hints, O. 2000. Ordovician eunicid polychaetes of Estonia and surrounding areas: a review of their distribution and diversification. Review of Palaeobotany and Palynology,113, 41–55.
Holland, C. H. 1981. Cambrian and Ordovician of the Paratectonic Caledonids. In A Geology of Ireland (Holland, C. H., ed.), pp. 41–64. Scottish Academic Press, Edinburgh.
Jaanusson, V. 1956. Untersuchungen über den obersordovizischen Lyckholm-Stufenkomplex in Estland. The Bulletin of the Geological Institutions of Uppsala, XXXVI, 369–400.
Jaanusson, V. 1982. Description of the sequence. In Ordovician of Öland. Guide to Excursion 3 – IV International Symposium on the Ordovician System (Jaanusson, V. & Mutvei, H., eds), pp. 1–9. Oslo.
Jaanusson, V. & Bassett, M. G. 1993. Orthambonites and related Ordovician brachiopod genera. Palaeontology, 36, 21–63.
Kaljo, D., Hints, L., Martma, T., Nõlvak, J. & Oraspõld, A. 2004. Late Ordovician carbon isotope trend in Estonia, its significance in stratigraphy and environmental analysis. Palaeogeography, Palaeoclimatology, Palaeoecology, 210, 165–185.
Männil, R. 1966. Istoriya razvitiya Baltijskogo bassejna v ordovike [Evolution of the Baltic Basin during the Ordovician]. Valgus, Tallinn, 200 pp. [in Russian, with English summary].
Männil, R. & Meidla, T. 1994. The Ordovician System of the East European Platform (Estonia, Latvia, Lithuania, Byelorussia, parts of Russia, the Ukraine and Moldova). In The Ordovician System of the East European Platform and Tuva (Southeastern Russia) (Webby, B. D., Ross, R. J. & Zhen, Y. Y., eds), IUGS Publication, 28, A, 1–55.
Männil, R. & Rõõmusoks, A. 1984. A revision of the lithostratigraphic subdivision of the Ordovician of North Estonia.
In Stratigrafiya drevnepaleozojskikh otlozhenij Pribaltiki [Stratigraphy of Early Palaeozoic deposits of the East Baltic] (Männil, R. M. & Mens, K. M., eds), pp. 52–62. Tallinn [in Russian].
Nestor, H. & Einasto, R. 1997. Ordovician and Silurian carbonate sedimentation basin. In Geology and Mineral Resources of Estonia (Raukas, A. & Teedumäe, A., eds), pp. 192–204. Estonian Academy Publishers, Tallinn.
Neuman, R. B. 1994. Late Ordovician (Ashgill) Foliomena fauna brachiopods from northeastern Maine. Journal of Paleontology, 68, 1218–1234.
Nõlvak, J. 1980. Chitinozoans in biostratigraphy of the northern East Baltic Ashgillian. A preliminary report. Acta Palaeontologica Polonica, 25, 253–260.
Nõlvak, J. 1984. Rasprostranenie kislotoustojchivykh mikrofossilij v razrezakh ashgilla Severnoj Pribaltiki [Distribution of acid-resistant microfossils in the northern East Baltic Ashgillian]. Moscow: VINITI, No. 8209-8469, 70 pp. [in Russian].
Nõlvak, J. 1987. Vormsi Stage. In Geologiya i poleznye iskopaemye Rakvereskogo fosforitonosnogo rajona [Geology and mineral resources of the Rakvere Phosphorite-bearing area] (Puura, V., ed.), pp. 66–67. Valgus Publishers, Tallinn [in Russian].
Nõlvak, J. 1988. Upper Ordovician chitinozoans of the Central-Lithuanian Depression. Moscow: VINITI, No. 7811-B88, 55 pp. [in Russian, with English summary].
Nõlvak, J. 2001. Distribution of chitinozoans. In Valga (10) Drill Core (Põldvere, A., ed.), Estonian Geological Sections, 3, 8–10, App. 8.
Nõlvak, J. 2003. Distribution of Ordovician chitinozoans. In Ruhnu (500) Drill Core (Põldvere, A., ed.), Estonian Geological Sections, 5, 23–25, App. 22, 23 on CD ROM.
Nõlvak, J. & Grahn, Y. 1993. Ordovician chitinozoan zones from Baltoscandia. Review of Palaeobotany and Palynology, 79, 245–269.
Nõlvak, J., Hints, O. & Männik, P. 2006. Ordovician timescale in Estonia: recent developments. Proceedings of the Estonian Academy of Sciences, Geology, 55, 95–108.
Oraspõld, A. 1991. Microlithology of the boundary beds between Vormsi and Pirgu stages [O3] (in Paluküla stone pit in Island Hiiumaa). Acta et Commentationes Universitatis Tartuensis, 934, 13–21 [in Estonian, with English summary].
Oraspõld, A. & Kala, E. 1982. Lithology of the Vormsi Stage in Estonia. Acta et Commentationes Universitatis Tartuensis, 527, 51–74 [in Russian,with English summary].
Popov, L., Nõlvak, J. & Holmer, L. 1994. Late Ordovician lingulate brachiopods from Estonia. Palaeontology, 37, 627–650.
Rong, J.-Y. & Zhan, R.-B. 1996. Distribution and ecological evolution of the Foliomena fauna (Late Ordovician brachiopods). In Centennial Memorial Volume of Prof. Sun Yunzhu: Palaeontology and Stratigraphy (Wang, H.-Z. & Wang, X.-L., eds), pp. 90–97. China University of Geosciences Press, Wuhan.
Rõõmusoks, A. K. 1960. Ordovician System. In Geologiya SSSR, Tom XXVIII, Éstonskaya SSR. Geologicheskoe opisanie i poleznye iskopaemye [Geology of USSR, Vol. XXVIII, Estonian SSR. Geological description and mineral resources] (Orviku, K. K., ed.), pp. 55–113. Gostoptekhizdat, Moskva [in Russian].
Rõõmusoks, A. 1966. Stratigrafiya viruskoj i har¢yuskoj serij (ordovik) Severnoj Éstonii [Stratigraphy of the Viru and Harju Series (Ordovician) of northern Estonia], Vol. 2. A dissertation for the Doctor’s degree in geological and mineralogical sciences. Manuscript. Moscow–Tartu, 1227 pp. [in Russian].
Schmidt, F. 1881. Revision der ostbaltischen silurischen Trilobiten nebst geognostischer Übersicht des ostbaltischen Silurgebiets. Abt. I. Phacopiden, Cheiruriden und Encrinuriden. Mémoires de l¢Academie Impériale des Sciences de St.-Petersbourg, VII sér., t. XXX, No. 1, 1–238.
Sheehan, P. M. 1987. Late Ordovician (Ashgillian) brachiopods from the region of the Sambre and Meuse Rivers, Belgium. Bulletin de l¢Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre, 57, 5–81.
Tuuling, I. & Flodén, T. 2000. Late Ordovician carbonate buildup environment and erosional features northeast of Gotland, northern Baltic Proper. GFF, 122, 237–249.
Ulst, R. Z., Gailite, L. K. & Yakovleva, V. I. 1982. Ordovik Latvii [Ordovician of Latvia]. Zinatne, Riga, 294 pp.[in Russian].
Vanmeirhaeghe, J. & Verniers, J. 2004. Chitinozoan bio- and lithostratigraphical study of the Ashgill Fosses and Génicot Formations (Condroz Inlier, Belgium). Review of Palaeobotany and Palynology, 130, 241–267.
Villas, E., Hammann, W. & Harper, D. A. T. 2002. Foliomena fauna (Brachiopoda) from the Upper Ordovician of Sardinia. Palaeontology, 45, 267–295.
Warburg, E. 1925. The trilobites of the Leptaena Limestone in Dalarne. Bulletin of the Geological Institution of the University of Upsala, 17, 1–446.
Webby, D. W., Elias, R. J., Young, G. A., Neuman, B. E. E. & Kaljo, D. 2004. Corals. In The Great Ordovician Biodiversification Event (Webby, B. D., Paris, F., Droser, M. L. & Percival, I. G., eds), pp. 124–146. Columbia University Press, New York.
Williams, A., Strachan, I., Bassett, D. A., Dean, W. T., Ingham, J. K., Wright, A. D. & Whittington, H. B. 1972. A correlation of Ordovician rocks in the British Isles. Geological Society of London, Special Report, 3, 1–74.
Wiman, C. 1907. Über die Fauna des westbaltischen Leptaenakalks. Arkiv för Zoologi, 3, 24, 1–20.
Wright, A. D. 1963. The fauna of the Portrane Limestone, I. Bulletin of the British Museum (Natural History), Geology, 8, 223–254.
Wright, A. D. 1964. The fauna of the Portrane Limestone, II. Bulletin of the British Museum (Natural History), Geology, 9, 159–256.
Wright, A. D. 1993. A homoeomorphy of the articulate brachiopod Dicoelosia from the Upper Ordovician Hulterstad faunaof Öland, Sweden. Geologiska Föreningens i Stockholm Förhandlingar, 115, 65–75.
