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Chitinozoan biostratigraphy of the Silurian Wenlock–Ludlow boundary succession of the Long Mountain, Powys, Wales

Published online by Cambridge University Press:  26 June 2015

THOMAS STEEMAN ,
THIJS R. A. VANDENBROUCKE ,
MARK WILLIAMS ,
JACQUES VERNIERS ,
VINCENT PERRIER ,
DAVID J. SIVETER ,
JAMES WILKINSON ,
JAN ZALASIEWICZ  and
POUL EMSBO
THOMAS STEEMAN*
Affiliation:
Research Unit Palaeontology, Department of Geology and Soil Sciences, Ghent University, Krijgslaan 281/S8, Belgium
THIJS R. A. VANDENBROUCKE
Affiliation:
Research Unit Palaeontology, Department of Geology and Soil Sciences, Ghent University, Krijgslaan 281/S8, Belgium UMR 8198 du CNRS: Evo-Eco-Paleo, Université Lille 1, Avenue Paul Langevin, bâtiment SN5, 59655 Villeneuve d'Ascq, France
MARK WILLIAMS
Affiliation:
Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom
JACQUES VERNIERS
Affiliation:
Research Unit Palaeontology, Department of Geology and Soil Sciences, Ghent University, Krijgslaan 281/S8, Belgium
VINCENT PERRIER
Affiliation:
Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom
DAVID J. SIVETER
Affiliation:
Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom
JAMES WILKINSON
Affiliation:
Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom
JAN ZALASIEWICZ
Affiliation:
Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom
POUL EMSBO
Affiliation:
USGS, CMERSC, Denver Federal Center, Denver, CO 80225, USA
*
†Corresponding author: thomas.steeman@ugent.be
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Abstract

Systematic collecting through the upper Wenlock (upper Homerian) and lower Ludlow (Gorstian and lowermost Ludfordian) Silurian rock succession of the Long Mountain, Powys, Wales, identifies some 48 chitinozoan species that distinguish four biozones, two subzones and an interregnum. Consideration of the chitinozoan biozones together with those of the graptolites enables a local three-fold subdivision of the late Homerian lundgreni graptolite Biozone, and the distinction of lower and upper intervals for the Gorstian incipiens graptolite Biozone. The base of the Ludlow Series in the Long Mountain more or less equates to the base of the Cingulochitina acme chitinozoan Biozone, although no key chitinozoan first or last appearance datums are associated with the series boundary itself. The new graptolite–chitinozoan biozonation allows enhanced correlation between upper Wenlock and lower Ludlow sedimentary deposits of the Lower Palaeozoic Welsh depositional basin and those of the palaeo-shelf in the stratotype Wenlock and Ludlow areas of Shropshire. Chitinozoans seem affected by the phenomena that caused the late Wenlock ‘Mulde extinction’ in graptolites but, with the final disappearance of 9 species and re-appearance of 11 species following an interval of overall low diversity, they seem to have suffered less severely than their macro-zooplanktonic contemporaries.

Keywords

chitinozoansgraptolitesbiostratigraphyWelsh BasinWenlock–Ludlow
Type
Original Articles
Information
Geological Magazine , Volume 153 , Issue 1 , January 2016 , pp. 95 - 109
Copyright
Copyright © Cambridge University Press 2015 

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References

Calner, M. 2008. Silurian global events – At the tipping point of climate change. In Mass Extinctions (ed. Elewa, A. M. T.), pp. 21–58. Berlin, Heidelberg: Springer-Verlag.CrossRefGoogle Scholar
Cave, R. 2008. Geology of the Welshpool district – a brief explanation of the geologic map, sheet explanation of the British Geological Society, 1:50 000, Sheet 151 Welshpool (England and Wales). British Geological Survey, 38 pp.Google Scholar
Cave, R. & Waters, R. A. 2008. Welshpool, England and Wales Sheet 151, bedrock and superficial deposits, 1:50 000. British Geological Survey.Google Scholar
Cherns, L., Cocks, L. R. M., Davies, J.R., Hillier, R. D., Waters, R. A. & Williams, M. 2006. Silurian: the influence of extensional tectonics and sea-level changes on sedimentation in the Welsh Basin and on the Midland Platform. In The Geology of England and Wales (eds Brenchley, P. J. & Rawson, P. F.), pp. 75–102. Geological Society of London.CrossRefGoogle Scholar
Cramer, B. D., Condon, D. J., Söderlund, U., Marshall, C., Worton, G. J., Thomas, A. T., Calner, M., Ray, D. C., Perrier, V., Boomer, I., Patchett, P. J. & Jeppsson, L. 2012. U-Pb (zircon) age constraints on the timing and duration of Wenlock (Silurian) palaeocommunity collapse and recovery during the ‘Big Crisis’. GSA Bulletin 124, 1841–57.CrossRefGoogle Scholar
Davies, J. R., Waters, R. A., Molyneux, S. G., Williams, M., Zalasiewicz, J. A., Vandenbroucke, T. R. A. & Verniers, J. 2013. A revised sedimentary and biostratigraphical architecture for the Type Llandovery area, Central Wales. Geological Magazine 150, 300–32.CrossRefGoogle Scholar
Dufka, P. 1995. Chitinozoans from the Sheinwoodian/Homerian boundary beds (Wenlock) in the Prague Basin (Barrandian, Bohemia). Review of Palaeobotany and Palynology 86, 135–45.CrossRefGoogle Scholar
Grahn, Y. & Paris, F. 2011. Emergence, biodiversification and extinction of the chitinozoan group. Geological Magazine 148, 226–36.CrossRefGoogle Scholar
Jaeger, H. 1959. Graptolithen und stratigraphie des Jüngsten Thüringer Silurs. Abhandlungen der Deutschen Akademie der Wissenschaften zu Berlin 2, 1–197.Google Scholar
Jaeger, H. 1991. New standard graptolite zonal sequence after the ‘big crisis’ at the Wenlockian/Ludlovian boundary (Silurian). Neues Jahrbuch für Geologie und Paläontologie 182, 303–54.CrossRefGoogle Scholar
Laufeld, S. 1974. Silurian chitinozoa from Gotland. Fossils and Strata 5, 1–130.CrossRefGoogle Scholar
Louwye, S., Van Grootel, G. & Verniers, J. 1992. The stratigraphy of the type locality of the late Wenlock/early Ludlow Mont Godart Formation and the early Ludlow Ronquières Formation, Brabant Massif, Belgium. Annales de la Société géologique de Belgique 115, 307–31.Google Scholar
Loydell, D. K., Nestor, V. & Männik, P. 2010. Integrated biostratigraphy of the lower Silurian of the Kolka-54 core, Latvia. Geological Magazine 147, 253–80.CrossRefGoogle Scholar
Mullins, G. L. & Aldridge, R. J. 2004. Chitinozoan biostratigraphy of the basal Wenlock series (Silurian) global stratotype section and Point. Palaeontology 47, 745–73.CrossRefGoogle Scholar
Mullins, G. L., Aldridge, R. J. & Siveter, D. J. 2004. Microplankton associations, biofacies and palaeoenvironment of the type lower Ludlow Series, Silurian. Review of Palaeobotany and Palynology 130, 163–94.CrossRefGoogle Scholar
Mullins, G. L. & Loydell, D. K. 2001. Integrated Silurian chitinozoan and graptolite biostratigraphy of the Banwy river section, Wales. Palaeontology 44, 731–81.CrossRefGoogle Scholar
Mullins, G. L. & Loydell, D. K. 2002. Integrated lower Silurian chitinozoan and graptolite biostratigraphy of Buttington Brick Pit, Wales. Geological Magazine 139, 89–96.CrossRefGoogle Scholar
Nestor, V. 1990. Silurian chitinozoans. In Field Meeting, Estonia. An Excursion Guidebook (eds. Kaljo, D. & Nestor, V.), pp. 80–83. Institute of Geology, Estonian Academy of Sciences.Google Scholar
Nestor, V. 1994. Early Silurian chitinozoans of Estonia and North Latvia. Academia 4, 1–163.Google Scholar
Nestor, V. 1997. Reflection of Wenlock oceanic episodes and events on the chitinozoans succession of Estonia. Proceedings of the Estonian Academy of Sciences, Geology 46, 199–26.CrossRefGoogle Scholar
Nestor, V. 2003. Distribution of Silurian chitinozoans. In Ruhnu (500) Drill Core (ed. Põldvere, A.), pp. 13–14. Estonian Geological Sections 5.Google Scholar
Nestor, V. 2007. Chitinozoans in the Wenlock-Ludlow boundary beds of the East Baltic. Estonian Journal of Earth Sciences 56, 109–28.CrossRefGoogle Scholar
Nestor, V. 2008. Reflection of the Mulde Event in the chitinozoan succession of the East Baltic. In The Seventh Baltic Stratigraphic Conference, Abstracts and Field Guide (eds Hints, O., Ainsaar, L., Männik, P. & Meidla, T.), p. 49. Geological Society of Estonia.Google Scholar
Nestor, V. 2009. Biostratigraphy of the Ludlow chitinozoans from East Baltic drill cores. Estonian Journal of Earth Sciences 58, 170–84.CrossRefGoogle Scholar
Nestor, V. 2012. A summary and revision of the East Baltic Silurian chitinozoan biozonation. Estonian Journal of Earth Sciences 61, 242–60.CrossRefGoogle Scholar
Nestor, V. & Einasto, R. 1997. Correlation of some Wenlock outcrop sections of Gotland with the Ohesaare section of Saaremaa, Estonia. Proceedings of the Estonian Academy of Sciences, Geology 46, 155–68.Google Scholar
Pittau, P., Cotza, F., Cristini, S., Del Rio, M. & Loi, M. 2006. Palaeontologic and biogeochemical characterization of the Cyrtograptus lundgreni event in the black shales of eastern Mid-Sardinia, Italy. Lethaia 39, 111–27.CrossRefGoogle Scholar
Porębska, E., Kozłowska-Dawidziuk, A. & Masiak, M. 2004. The lundgreni event in the Silurian of the East European Platform, Poland. Palaeogeography, Palaeoclimatology, Palaeoecology 213, 271–94.CrossRefGoogle Scholar
Rushton, A. W. A. 1990. Ordovician graptolite biostratigraphy in the Welsh Basin: a review. Journal of the Geological Society 147, 611–14.CrossRefGoogle Scholar
Sutherland, S. J. E. 1994. Ludlow chitinozoans from the type area and adjacent regions. Monograph of the Palaeontographical Society, London 148, 1–104.Google Scholar
Torsvik, T. H. & Cocks, L. R. M. 2013. Gondwana from top to base in space and time. Gondwana Research 24, 999–1030.CrossRefGoogle Scholar
Vandenbroucke, T. R. A. 2008. An Upper Ordovician Chitinozoan Biozonation in British Avalonia (England & Wales). Lethaia 41, 275–94.CrossRefGoogle Scholar
Vandenbroucke, T. R. A., Ancilletta, A., Fortey, R. A. & Verniers, J. 2009. A modern assessment of Ordovician chitinozoans from the Shelve and Caradoc areas, Shropshire, and their significance for correlation. Geological Magazine 146, 216–36.CrossRefGoogle Scholar
Vandenbroucke, T. R. A., Hennissen, J., Zalasiewicz, J. A. & Verniers, J. 2008a. New chitinozoans from the historical type area of the Hirnantian Stage and additional key sections in the Wye Valley, Wales, UK. Geological Journal 43, 397–414.CrossRefGoogle Scholar
Vandenbroucke, T. R. A., Rickards, B. & Verniers, J. 2005. Upper Ordovician Chitinozoan biostratigraphy from the type Ashgill Area (Cautley district) and the Pus Gill section (Dufton district, Cross Fell Inlier), Cumbria, Northern England. Geological Magazine 142, 783–807.CrossRefGoogle Scholar
Vandenbroucke, T. R. A., Williams, M., Zalasiewicz, J. A., Davies, J. R. & Waters, R. A. 2008b. Integrated Upper Ordovician graptolite-chitinozoan biostratigraphy of the Cardigan and Whitland areas, southwest Wales. Geological Magazine 145, 199–214.CrossRefGoogle Scholar
Verniers, J. 1982. The Silurian Chitinozoa of the Mehaigne area (Brabant Massif, Belgium). Belgian Geological Survey, Professional Paper 192, 76 pp.Google Scholar
Verniers, J. 1999. Calibration of Wenlock Chitinozoa versus graptolite biozonation in the Wenlock of Builth Wells district (Wales, UK), compared with other areas in Avalonia and Baltica. Bollettino della Società Paleontologica Italiana 38, 359–80.Google Scholar
Verniers, J., Nestor, V., Paris, F., Dufka, P., Sutherland, S. & Van Grootel, G. 1995. A global Chitinozoa biozonation for the Silurian. Geological Magazine 132, 651–66.CrossRefGoogle Scholar
Verniers, J., Van Grootel, G., Louwye, S. & Diependale, B. 2002. The chitinozoan biostratigraphy of the Silurian of the Ronquières-Monstreux area (Brabant Massif, Belgium). Review of Palaeobotany and Palynology 118, 287–322.CrossRefGoogle Scholar
Wrona, R. 1980. Upper Silurian Lower Devonian Chitinozoa from the subsurface of southeastern Poland. Palaeontologia Polonica 41, 103–65.Google Scholar
Zalasiewicz, J. A. 1990. Silurian graptolite biostratigraphy in the Welsh Basin. Journal of the Geological Society 147, 619–22.CrossRefGoogle Scholar
Zalasiewicz, J. A., Taylor, L., Rushton, A. W. A., Loydell, D. K., Rickards, R. B. & Williams, M. 2009. Graptolites in British stratigraphy. Geological Magazine 146, 785–850.CrossRefGoogle Scholar
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