Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-22T19:00:04.379Z Has data issue: false hasContentIssue false
  • English
  • Français

Silurian reefs off Saaremaa and their extension towards Gotland, central Baltic Sea

Published online by Cambridge University Press:  30 April 2013

IGOR TUULING  and
TOM FLODÉN
IGOR TUULING*
Affiliation:
Institute of Ecology and Earth Sciences, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
TOM FLODÉN
Affiliation:
Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden
*
†Author for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The Silurian reefs off Saaremaa in the Baltic Sea were studied by means of high-resolution seismic reflection profiling. The abundance and diversity of the reefs increases off Saaremaa concomitantly with the deepening of the Baltic Silurian Basin towards Gotland. The peak of the reefs around Saaremaa occurred during the Middle Wenlock. The reef facies retreated further off Saaremaa during the Late Wenlock, became episodically restored around the island during the early Ludlow and finally ceased during the late Ludlow. A similar SW–NE–SW migration of reefs reflects an alternating transgressive–regressive pattern in the nearshore shallow shelf environment, where already minor sea-level fluctuations strongly influenced the conditions for reef growth. During the early Wenlock, a bathymetric break with a large barrier-reef-like structure divided the shallow shelf offshore Saaremaa facially into back-reef and southerly sloping fore-reef areas. The width of this SW-migrating barrier (c. 8 km) and the extent of reef bodies within it (c. 4 km) are the largest known in the Baltic region. During the Silurian, the reefs between Saaremaa and Gotland were flourishing to a much larger extent than is visible today. The primary Silurian reef pattern was increasingly destroyed towards Gotland by later erosion. This has resulted in a large area void of Wenlock reefs off northern Gotland. Off southern Gotland, the narrow conical low-energy deeper-water reefs prevail, as the wave-agitated shallow-water facies with larger and lenticular Wenlock and Ludlow reefs are largely eroded around the Gotland Deep.

Keywords

Estoniaseismic profilingseismostratigraphyreef faciesPleistocene glacial erosion
Type
Original Articles
Information
Geological Magazine , Volume 150 , Issue 5 , September 2013 , pp. 923 - 936
Copyright
Copyright © Cambridge University Press 2013 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aaloe, A. & Einasto, R. 1970. Biohermal limestones. In Silur Estonii (The Silurian of Estonia (ed Kaljo, D.), pp. 41–6. Valgus: Tallinn (in Russian with English summary).Google Scholar
Aaloe, A. & Nestor, H. 1977. Biohermal facies in the Juuru Stage (Lower Llandoverian) in North-West Estonia. In Fatsii i fauna Silura Pribaltiki (Facies and fauna of the Baltic Silurian) (ed Kaljo, D.), pp. 71–88. Academy of Sciences of the Estonian SSR: Tallinn (in Russian with English summary).Google Scholar
Baarli, B. G., Johnson, M. E. & Antoshkina, A. I. 2003. Silurian Stratigraphy and Paleogeography of Baltica. In Silurian Lands and Seas. Paleogeography outside of Laurentia (eds Landing, Ed & Johnson, M. E.), pp. 3–34. New York State Museum Bulletin vol. 493.Google Scholar
Bassett, M. G., Kaljo, D. & Teller, L. 1989. The Baltic region. In A Global Standard for the Silurian System (eds Holland, C. H. & Bassett, M. G.), pp. 158–170. National Museum of Wales, Geological Series, vol. 9.Google Scholar
Bjerkéus, M. & Eriksson, M. 2001. Late Silurian reef development. GFF 123, 169–79.Google Scholar
Copper, P. & Brunton, F. 1991. A global review of Silurian reefs. Special Papers in Palaeontology 44, 225–59.Google Scholar
Einasto, R. 1990. Kaugatuma cliff. In Field Meeting in Estonia. An Excursion Guidebook (eds Kaljo, D. & Nestor, H.), pp. 174–5. Estonian Academy of Sciences: Tallinn.Google Scholar
Flodén, T. 1980. Seismic stratigraphy and bedrock geology of the Central Baltic. Stockholm Contributions in Geology 35, 240 pp.Google Scholar
Flodén, T. 1981. Current geophysical methods and data processing techniques for marine geological research in Sweden. Stockholm Contributions in Geology 37, 49–66.Google Scholar
Flodén, T., Bjerkéus, M., Tuuling, I. & Eriksson, M. 2001. A reefal succession in the Gotland area, Baltic Sea. GFF 123, 137–52.Google Scholar
Flodén, T., Söderberg, P., Tuuling, I. & Wahlberg, M. 1995. The Östergarn reef - reconstruction of a Silurian barrier reef complex east of Gotland, Baltic Sea. In Proceedings of the Third Marine Geological Conference, ‘The Baltic’ (ed Mojski, J. E.), pp. 37–43. Prace Panstwowego Instytutu Geologicznego vol. 149.Google Scholar
Jeppsson, L., Eriksson, M. E. & Calner, M. 2006. A latest Llandovery to latest Ludlow high-resolution biostratigraphy based on the Silurian on Gotland – a summary. GFF 128, 109–14.Google Scholar
Jeppsson, L., Viira, V. & Männik, P. 1994. Silurian conodont-based correlations between Gotland (Sweden) and Saaremaa (Estonia). Geological Magazine 131, 201–18.Google Scholar
Kaljo, D. & Jürgenson, E. 1977. Sediment facies of the East Baltic Silurian. In Fatsii i fauna Silura Pribaltiki (Facies and fauna of the Baltic Silurian) (ed Kaljo, D.), pp. 122–48. Academy of Sciences of the Estonian SSR: Tallinn (in Russian with English summary).Google Scholar
Kaljo, D., Nestor, H. & Einasto, R. 1991. Aspects of Silurian carbonate platform sedimentation. Special Papers in Palaeontology 44, 205–24.Google Scholar
Klaamann, E. & Einasto, R. 1982. Coral reefs of Baltic Silurian (structure, facies, relations). In Ecostratigraphy of the East Baltic Silurian (eds Kaljo, D. & Klaamann, E.), pp. 35–40. Valgus: Tallinn.Google Scholar
Lapinskas, P. 1998. Petroleum potential of Silurian non-structural traps in Lithuania. In Perspectives of Petroleum Exploration in the Baltic region: Proceedings of the international conference, 21–24 October, 1998, Vilnius, Lithuania (eds Suveizdis, P. & Zdanaviciute, O.), pp. 30–5. Institute of Geology: Vilnius.Google Scholar
Manten, A. A. 1971. Silurian Reefs of Gotland. Elsevier, 539 pp.Google Scholar
Martinsson, A. 1967. The succession and correlation of ostracode faunas in the Silurian of Gotland. Geologiska Föreningens i Stockholms Förhandlingar 89, 350–86.Google Scholar
Murchison, R. I. 1847. On the Silurian and associated rocks in Dalecarlia and on the succession from Lower to Upper Silurian in Smoland, Öland and Gotland and Scania. Journal of the Geological Society of London 3, 1–48.Google Scholar
Nestor, H. 1990. Basin development and facies models. In Field meeting in Estonia. An Excursion Guidebook (eds Kaljo, D. & Nestor, H.), pp. 33–36. Estonian Academy of Sciences: Tallinn.Google Scholar
Nestor, H. 1995. Ordovician and Silurian reefs in the Baltic area. In Coral Reefs in the Past, Present and Future (eds Lathiliere, B. & Geiser, J.), pp. 39–47. Publications Service Géologique: Luxembourg.Google Scholar
Nestor, H. 1997. Silurian. In Geology and Mineral Resources of Estonia (eds Raukas, A. & Teedumäe, A.), pp. 89–105. Estonian Academy Publishers: Tallinn.Google Scholar
Nestor, H. & Einasto, R. 1982. Application of shelf and slope concepts to the Silurian Baltic Basin. In Ecostratigraphy of the East Baltic Silurian (eds Kaljo, D. & Klaamann, E.), pp. 17–24. Valgus: Tallinn.Google Scholar
Nestor, H. & Einasto, R. 1997. Ordovician and Silurian carbonate sedimentary basin. In Geology and Mineral Resources of Estonia (eds Raukas, A. & Teedumäe, A.), pp. 192–95. Estonian Academy Publishers: Tallinn.Google Scholar
Nestor, H. & Nestor, V. 1977. A quantitative study of two early Llandoverian bioherms on the Isle Hiiumaa (Estonian SSR). Eesti Teaduste Akadeemia Toimetised, Keemia, Geoloogia 26, 122–28 (in Russian with English summary).Google Scholar
Neuman, B. & Kershaw, S. 1991. Gotland/Sweden Silurian reefs and coral bearing strata. Exursion Guide-book. VI International Symposium of Fossil Cnidaria including Archaeocyatha and Porifera. Dupliseringsseksjonen Realfagbygget, University of Bergen, Norway, 111 pp.Google Scholar
Riding, R. 1981. Composition, structure and environmental setting of Silurian bioherms and biostromes in northern Europe. In European Fossil Reef Models (ed Toomey, D. F.), pp. 41–83. The Society of Economic Paleontologists and Mineralogists, Special Publication 30.Google Scholar
Rõõmusoks, A. 1983. Eesti Aluspõhja Geoloogia. Valgus: Tallinn, 224 pp.Google Scholar
Tuuling, I. 1998. Shipborne geophysical study of an Ordovician-Silurian carbonate platform, Fårö-Hiiumaa area, north-eastern Baltic Sea. Doctoral Thesis. Meddelanden från Stockholms Universitets Institution för Geologi och Geokemi, 301. Sandlund & Co Grafiska: Stockholm.Google Scholar
Tuuling, I. & Flodén, T. 2000. Late Ordovician carbonate buildups and erosional features north-east of Gotland, northern Baltic Sea. GFF 122, 237–49.Google Scholar
Tuuling, I. & Flodén, T. 2001. Structure and relief of the bedrock sequence of the northern Baltic Proper. GFF 123, 35–49.Google Scholar
Tuuling, I. & Flodén, T. 2007. The Ordovician-Silurian boundary beds between Saaremaa and Gotland, Baltic Sea, based on high resolution seismic data. Geological Quarterly 51, 217–29.Google Scholar
Tuuling, I. & Flodén, T. 2009 a. The Llandovery–lowermost Wenlock sequence in the Baltic Sea between Saaremaa and Gotland; subdivision, thicknesses and correlation, based on marine seismic studies. Marine Geology, 267, 55–70.Google Scholar
Tuuling, I. & Flodén, T. 2009 b. Seismic correlation of Palaeozoic rocks across the northern Baltic Proper - Swedish-Estonian project since 1990, a review. Estonian Journal of Earth Sciences 58, 273–85.Google Scholar
Tuuling, I. & Flodén, T. 2011. Seismic stratigraphy, architecture and outcrop pattern of the Wenlock-Přidoli sequence offshore Saaremaa, Baltic Sea. Marine Geology 281, 14–26.Google Scholar
Zdanaviciute, O. & Lazauskiene, J. 2007. The petroleum potential of the Silurian succession in Lithuania. Journal of Petroleum Geology 30, 325–37.Google Scholar