Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-23T16:20:08.721Z Has data issue: false hasContentIssue false
  • English
  • Français

Cambrian and Ordovician stratigraphy related to structure and seismic profiles in the western part of the English Midlands

Published online by Cambridge University Press:  01 May 2009

N. J. P. Smith  and
A. W. A. Rushton
N. J. P. Smith
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
A. W. A. Rushton
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

In England the Cambrian successions include relatively continuous, dominantly argillaceous sequences (Nuneaton area, > 900 m thick) and arenaceous successions punctuated by hiatuses (Malvern, Shropshire). The Tremadoc (lower Ordovician) succeeds paraconformably; it is widespread, dominantly argillaceous and locally very thick (> 2000 m). Deposition of the lower Tremadoc is thought to have been rapid. Uplift of regional extent occurred in early Ordovician (post-Tremadoc) times and inversion of the basins, such as the Tremadoc Worcester Graben, occurred during the Variscan Orogeny. The disposition of the Cambrian–Tremadoc beneath the Upper Llandovery unconformity is thought to reflect the arrangement of basins and highs at that time. Evidence from seismic profiles indicates deposition in half-grabens. In the Welsh Borderland, evidence from outcrops and boreholes suggests that the St David's Series (Middle Cambrian) is locally thickened against syn-depositional faults. The thinning and local absence of the St David's Series across such faults is attributed to the influence of tilt-block highs. Rifting and tilting allowed thick Tremadoc to accumulate (e.g. in a precursor Worcester Graben), but evidence for the direction of thickening is masked by lack of seismic markers and by the effect of pre-landovery erosion.

Type
Articles
Information
Geological Magazine , Volume 130 , Issue 5 , September 1993 , pp. 665 - 671
Copyright
Copyright © Cambridge University Press 1993

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

Brasier, M. D., Anderson, M. M. & Corfield, R. M. 1992. Oxygen and carbon isotope stratigraphy of early Cambrian carbonates in southeastern Newfoundland and England. Geological Magazine 129, 265–79.CrossRefGoogle Scholar
Cave, R. 1977. Geology of the Malmesbury District. Memoir of the Geological Survey of Great Britain, Sheet 251 (England & Wales).Google Scholar
Chadwick, R. A. 1986. Extension tectonics in the Wessex Basin, southern England. Journal of the Geological Society, London 143, 465–88.CrossRefGoogle Scholar
Chadwick, R. A. & Smith, N. J. P. 1988. Evidence of negative structural inversion beneath central England from new seismic reflection data. Journal of the Geological Society, London 145, 519–22.CrossRefGoogle Scholar
Cobbold, E. S. 1927. The stratigraphy and geological structure of the Cambrian area of Comley (Shropshire). Quarterly Journal of the Geological Society of London 83, 551–73.CrossRefGoogle Scholar
Cobbold, E. S. & Pocock, R. W. 1934. The Cambrian area of Rushton (Shropshire). Philosophical Transactions of the Royal Society of London, Series B 223, 305–409.Google Scholar
Conway Morris, S. & Rushton, A. W. A. 1988. Precambrian to Tremadoc biotas in the Caledonides. In The Caledonian–Appalachian Orogen (eds Harris, H. A. and Fettes, D. J.), pp. 93–109. Special Publication Geological Society of London no. 38.Google Scholar
Cox, A. H. 1912. On an inlier of Longmyndian and Cambrian rocks at Pedwardine (Herefordshire). Quarterly Journal of the Geological Society of London 68, 364–73.CrossRefGoogle Scholar
Greig, D. C., Wright, J. E., Hains, B. A. & Mitchell, G. H. 1968. Geology of the country around Church Stretton, Craven Arms, Wenlock Edge and Brown Clee. Memoir of the Geological Survey of Great Britain, Sheet 166 (England & Wales).Google Scholar
Gries, R. 1983. Oil and gas prospecting beneath Precambrian of foreland thrust plates in Rocky Mountains. Bulletin of the American Association of Petroleum Geologists 67 (1) 1–28.Google Scholar
Hoffman, P. 1973. Evolution of an early Proterozoic continental margin: the Coronation Geosyncline and associated aulacogen of the northwestern Canadian Shield. Philosophical Transactions of the Royal Society of London A273, 547–81.Google Scholar
Kellaway, G. A. & Welch, F. B. A. 1948. Bristol and Gloucester District. 2nd ed. British Regional Geology. London: HMSO.Google Scholar
Levorsen, A. I. 1933. Studies in paleogeology. Bulletin of the American Association of Petroleum Geologists 17, 9, 1107–32.Google Scholar
McKerrow, W. S., Dewey, J. F. & Scotese, C. R. 1991. The Ordovician and Silurian development of the lapetus Ocean. Special Papers in Palaeontology 44, 165–78.Google Scholar
Pharaoh, T. C., Webb, P. C., Thorpe, R. S. & Beckinsale, R. D. 1987. Geochemical evidence for the tectonic setting of late Proterozoic volcanic suites in central England. In Geochemistry and Mineralization of Proterozoic Volcanic Suites (eds Pharaoh, T. C., Beckinsale, R. D. and Rickard, D.), pp. 541–52. Special Publication, Geological Society of London no. 33.Google Scholar
Pocock, R. W., Whitehead, T. H., Wedd, C. B. & Robertson, T. 1938. Shrewsbury District. Memoir of the Geological Survey of Great Britain, Sheet 152 (England & Wales).Google Scholar
Rushton, A. W. A. & Fortey, R. A. 1992. Tremadoc. In Atlas of Palaeogeography and Lithofacies (eds Cope, J. C. W., Ingham, J. K. and Rawson, P. F.), p. 24. Geological Society of London, Memoir no. 13.Google Scholar
Rushton, A. W. A., Hamblin, R. J. O. & Strong, G. E. 1988. The Croft Borehole in the Lilleshall Inlier of north Shropshire. Report of the British Geological Survey no. 19(3), 14 pp.Google Scholar
Smith, N. J. P. 1987. The deep geology of central England: the prospectivity of the Palaeozoic rocks. In Petroleum Geology of Northwest Europe (eds Brooks, J. and Glennie, K.), pp. 217–24. Graham & Trotman.Google Scholar
Smith, N. J. P. 1993. The case for exploration of deep plays in the Variscan fold belt and its foreland. In Petroleum Geology of Northwest Europe: Proceedings of the 4th Conference (ed. Parker, J. R.), (in press).Google Scholar
Stubblefield, C. J. & Bulman, O. M. B. 1927. The Shineton Shales of the Wrekin District. Quarterly Journal of the Geological Society of London 83, 96–146.CrossRefGoogle Scholar
Taylor, K. & Rushton, A. W. A. 1972. The pre-Westphalian geology of the Warwickshire Coalfield. Bulletin of the Geological Survey of Great Britain no. 35, 150 pp. [dated 1971].Google Scholar
Whittard, W. F. & Smith, S. 1944. Unrecorded inliers of Silurian rocks near Wickwar, Gloucestershire. Geological Magazine 81, 65–76.CrossRefGoogle Scholar
Wills, L. 1956. Concealed Coalfields. London: Blackie, 208 pp.Google Scholar
Woodcock, N. H. 1984. The Pontesford Lineament, Welsh Borderland. Journal of the Geological Society, London 141, 1001–14.CrossRefGoogle Scholar
Worssam, B. C., Ellison, R. A. & Moorlock, B. S. P. 1989. Geology of the country around Tewkesbury. Memoir of the British Geological Survey, Sheet 216 (England & Wales).Google Scholar