Skip to main content

Late Wenlock sequence stratigraphy in central England


The late Wenlock Series (Homerian Stage) of the northern Midland Platform (central England) comprises silty mudstones and limestones of the upper part of the Coalbrookdale and overlying Much Wenlock Limestone formations. Based on outcrop studies and borehole data, the sequence stratigraphical interpretation developed for the inliers of the West Midlands is slightly revised, and extended to the stratotype sections along Wenlock Edge. A single third-order cycle of sea-level change is identified, punctuated by a regressive–transgressive episode associated with a higher-order glacioeustatic cycle, allowing the upper Wenlock Series of the area to be divided into two subsequences (A and B). Subsequence A and the early transgressive systems tract began with regression associated with the basal sequence boundary in late Cyrtograptus lundgreni Biozone times. This was followed by a period of slow transgression or stillstand, allowing shallower water carbonate environments to prograde. A minor phase of regression followed, resulting in the generation of the shallowest water deposits of both the Lower Quarried Limestone and Farley members (of the Much Wenlock Limestone and Coalbrookdale formations, respectively). The overlying Subsequence B and the late transgressive systems tract are marked by transgression and a period of rapid sea-level fluctuation and are likely contained within the Gothograptus nassa Biozone. A minor highstand is widely recognizable at this time. The rest of Subsequence B consists of an initial phase of weak progradation (highstand systems tract), followed by a marked regression (falling stage systems tract) culminating in an erosive upper sequence boundary at or close to the top of the Monograptus ludensis Biozone, but within the uppermost Much Wenlock Limestone Formation. Above Subsequence B is a marked transgression into the Lower Elton Formation and the Ludlow Series. Both late Wenlock lowstands and the succeeding flooding events have been recognized on other palaeocontinents, reflecting the eustatic nature of sea-level changes reported here.

Corresponding author
Author for correspondence:
Hide All
Aldridge, R. J., Siveter, David J., Siveter, Derek J., Lane, P. D., Palmer, D. C. & Woodcock, N. H. 2000. British Silurian stratigraphy. Peterborough: Geological Conservation Review Series, Joint Nature Conservation Committee, xviii + 542 pp.
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, E. & Johnson, M. E.), pp. 3–34. New York State Museum Bulletin no. 493.
Barclay, W. J., Davies, J. R., Humpage, A. J., Waters, R. A., Wilby, P. R., Williams, M. & Wilson, D. 2005. Geology of the Brecon district, a brief explanation of the geological map. Sheet explanation of the British Geological Survey, 1:50 000 Sheet 213, Brecon (England and Wales). Keyworth, Nottingham: British Geological Survey.
Bassett, M. G. 1974. Review of the stratigraphy of the Wenlock Series in the Welsh Borderland and South Wales. Palaeontology 17, 145–77.
Bassett, M. G. 1976. A critique of diachronism, community distributions and correlation of the Wenlock–Ludlow boundary. Lethaia 9, 207–18.
Bassett, M. G. 1989. The Wenlock Series in the Wenlock area. In A global standard for the Silurian System (eds Holland, C. H. & Bassett, M. G.), pp. 5173. Cardiff: National Museum of Wales, Geological Series no. 9.
Bassett, M. G., Cocks, L. R. M., Holland, C. H., Rickards, R. B. & Warren, P. T. 1975. The type Wenlock Series. Institute of Geological Sciences Report no. 75/13, 1–19.
Brett, C. E., Boucot, A. J. & Jones, B. 1993. Absolute depth limits of Silurian benthic assemblages. Lethaia 26, 2540.
Brett, C. E., Ferretti, A., Histon, K. & Schönlaub, H.-P. 2007. Eustasy and basin dynamics of the Silurian of the Carnic Alps (Austria). Acta Palaeontologica Sinica 46, 43–9.
Butler, A. J. 1939. The stratigraphy of the Wenlock Limestone at Dudley. Quarterly Journal of the Geological Society of London 95, 3474.
Calner, M. 1999. Stratigraphy, facies development, and depositional dynamics of the Late Wenlock Fröjel Formation, Gotland, Sweden. Geologiska Föreningens i Stockholm förhandlingar 121, 1324.
Calner, M. 2005. Silurian carbonate platforms and extinction events – ecosystem changes exemplified from Gotland, Sweden. Facies 51, 584–91.
Calner, M. 2008. Silurian global events – at the tipping point of climate change. In Mass extinctions (ed. Elewa, A. M. T.), pp. 2158. Berlin and Heidelberg: Springer-Verlag.
Calner, M. & Jeppsson, L. 2002. Carbonate platform evolution and conodont stratigraphy during the middle Silurian Mulde Event, Gotland, Sweden. Geological Magazine 140, 173203.
Calner, M., Jeppsson, L. & Eriksson, M. J. 2004. Ytterholmen revisited – implications for the Later Wenlock stratigraphy of Gotland and coeval extinctions. Geologiska Föreningens i Stockholm förhandlingar 126, 231–41.
Calner, M. & Säll, E. 1999. Transgressive oolites onlapping a Silurian rocky shoreline unconformity, Gotland, Sweden. Geologiska Föreningens i Stockholm förhandlingar 121, 91100.
Caputo, M. V. 1998. Ordovician–Silurian glaciations and global sea-level changes. In Silurian cycles: Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic, and Tectonic Changes (eds Landing, E. & Johnson, M. E.), pp. 15–25. New York State Museum Bulletin no. 491.
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 Borderland and on the Midland Platform. In The Geology of England and Wales, 2nd ed. (eds Brenchley, P. J. & Rawson, P. F.), pp. 75102. London: The Geological Society.
Collings, A. V. J. 1989. A major regressive event at the top of the Much Wenlock Limestone Formation in the West Midlands. The Murchison Symposium; An International Symposium on The Silurian System. Program and Abstracts, p. 40.
Corfield, R. M., Siveter, Derek J., Cartlidge, J. E. & McKerrow, W. S. 1992. Carbon isotope excursions near the Wenlock–Ludlow (Silurian) boundary in the Anglo-Welsh area. Geology 20, 371–4.
Cramer, B. S., Kleffner, M. A. & Saltzman, M. R. 2006. The Late Wenlock Mulde positive carbon isotope excursion in North America. Geologiska Föreningens i Stockholm förhandlingar 128, 8590.
Dorning, K. J. 1983. Palynology and stratigraphy of the Much Wenlock Limestone Formation of Dudley, Central England. Mercian Geologist 9, 3140.
Dorning, K. J. & Bell, D. G. 1987. The Silurian shelf microfacies: acritarch distribution in the Much Wenlock Limestone Formation. In Micropalaeontology of carbonate environments (ed. Hart, M. B.), pp. 266–87. Chichester: Ellis Horwood Ltd.
Dorning, K. J. & Harvey, C. 1999. Wenlock cyclicity, palynology, and stratigraphy in the Buildwas, Coalbrookdale, and Much Wenlock Limestone formations, Shropshire, England. Bollettino della Societa Paleontologica Italia 38, 155–66.
Haq, B. U. & Schutter, S. R. 2008. A chronology of Paleozoic sea-level change. Science 322, 64–8.
Hurst, J. M. 1975. The diachronism of the Wenlock Limestone. Lethaia 8, 301–14.
Johnson, M. E. 2006. Relationship of Silurian sea-fluctuations to oceanic episodes and events. Geologiska Föreningens i Stockholm förhandlingar 128, 115–21.
Kaljo, D. & Martma, T. 2006. Application of carbon isotope stratigraphy to dating the Baltic Silurian rocks. Geologiska Föreningens i Stockholm förhandlingar 128, 123–9.
Kemp, A. E. S. 1991. Mid-Silurian pelagic and hemipelagic sedimentation and palaeoceanography. In The Murchison Symposium: Proceedings of an International Symposium on the Silurian System (eds Bassett, M. G. et al. ), pp. 261–99. Special Papers in Palaeontology 44.
Lawson, J. D. 1955. The geology of the May Hill Inlier. Quarterly Journal of the Geological Society of London 111, 85116.
Lenz, A. C., Noble, P. J., Masiak, M., Poulson, S. R. & Kozłowska, A. 2006. The lundgreni Extinction Event: integration of paleontological and geochemical data from Arctic Canada. Geologiska Föreningens i Stockholm förhandlingar 128, 153–8.
Loydell, D. K. 1998. Early Silurian sea-level changes. Geological Magazine 135, 447–71.
Loydell, D. K. & Fone, W. 1998. Graptolites from the Lower Elton Formation (Ludlow) of Shadwell Rock Quarry, Shropshire. Geological Journal 33, 147–8.
McLaughlin, P. I. & Brett, C. E. 2007. Signatures of sea-level rise on the carbonate margin of a Late Ordovician Foreland Basin: a case study from the Cincinnati Arch, USA. Palaios 22, 245–67.
Miller, K. G., Kominz, M. A., Browning, J. V., Wright, J. D., Mountain, G. S., Katz, M. E., Sugarman, P. J., Cramer, B. S., Christie-Blick, N. & Pekar, S. F. 2005. The Phanerozoic record of global sea-level change. Science 310, 1293–8.
Murchison, R. I. 1872. Siluria. The history of the oldest known rocks containing organic remains, with a brief description of the distribution of gold over the Earth, 5th ed. London: John Murray, xvi + 523 pp.
Pocock, R. W., Whitehead, T. A., Wedd, C. B. & Robertson, T. 1938. Shrewsbury district, including the Hanwood Coalfield. Memoir of the Geological Survey of Great Britain. HMSO: London, xii + 297 pp.
Ratcliffe, K. T. 1988. Oncoids as environmental indicators in the Much Wenlock Limestone Formation of the English Midlands. Journal of the Geological Society, London 145, 117–24.
Ratcliffe, K. T. & Thomas, A. T. 1999. Carbonate depositional environments in the late Wenlock of England and Wales. Geological Magazine 136, 189204.
Ray, D. C. & Thomas, A. T. 2007. Carbonate depositional environments, sequence stratigraphy and exceptional skeletal preservation in the Much Wenlock Limestone Formation (Silurian) of Dudley, England. Palaeontology 50, 197222.
Ross, R. J., Naeser, C. W., Izett, G. A., Obradovich, J. D., Bassett, M. G., Hughes, C. P., Cocks, L. R. M., Dean, W. T., Ingham, J. K., Jenkins, C. J., Rickards, R. B., Sheldon, P. R., Toghill, P., Whittington, H. B. & Zalasiewicz, J. 1982. Fission-track dating of British Ordovician and Silurian stratotypes. Geological Magazine 119, 135–53.
Schofield, D. I., Davies, J. R., Jones, N. S., Leslie, A. B., Waters, R. A., Williams, M., Wilson, D., Venus, J. & Hillier, R. D. 2009. Geology of the Llandovery district, a brief explanation of the geological map. Sheet Explanation of the British Geological Survey, 1:50000 Sheet 212, Llandovery (England and Wales). Keyworth, Nottingham: British Geological Survey.
Schofield, D. I., Davies, J. R., Waters, R. A., Wilby, P. R., Williams, M. & Wilson, D. 2004. Geology of the Builth Wells district, a brief explanation of the geological map. Sheet Explanation of the British Geological Survey, 1:50000 Sheet 196 Builth Wells (England and Wales). Keyworth, Nottingham: British Geological Survey.
Scoffin, T. P. 1971. The conditions of growth of the Wenlock reefs of Shropshire (England). Sedimentology 17, 173219.
Shergold, J. H. & Bassett, M. G. 1970. Facies and faunas at the Wenlock/Ludlow boundary of Wenlock Edge, Shropshire. Lethaia 3, 113–42.
Siveter, David J., Owens, R. M. & Thomas, A. T. 1989. Silurian field excursions: a geotraverse across Wales and the Welsh Borderlands, pp. 2335. Cardiff: National Museum of Wales, Geological Series no. 10.
White, D. E. 1974. The boundary between the Wenlock and Ludlow Series. Geological Magazine 111, 448–9.
Woodcock, N. H., Butler, A. J., Davies, J. R. & Waters, R. A. 1996. Sequence stratigraphical analysis of late Ordovician and early Silurian depositional systems in the Welsh Basin: a critical assessment. In Sequence Stratigraphy in British Geology (eds Hesselbo, S. & Parkinson, N.), pp. 197208. Geological Society of London, Special Publication no. 103.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Geological Magazine
  • ISSN: 0016-7568
  • EISSN: 1469-5081
  • URL: /core/journals/geological-magazine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed