Hostname: page-component-848d4c4894-wzw2p Total loading time: 0 Render date: 2024-05-06T01:30:05.546Z Has data issue: false hasContentIssue false
  • English
  • Français

A transition from diagenesis to greenschist facies within a major Variscan fold/thrust complex in SW England

Published online by Cambridge University Press:  05 July 2018

T. J. Primmer
T. J. Primmer*
Affiliation:
Department of Geology, University of Bristol, Queen's Building, University Walk, Bristol BS8 1TR
Get access Rights & Permissions [Opens in a new window]

Abstract

The north coast of Cornwall, from Bude to Newquay, provides a continuous section through a major Variscan fold/thrust complex. Illite crystallinity studies have revealed a transition from diagenesis in the north to greenschist facies metamorphism in the south in the Upper Palaeozoic succession. More detailed studies of mineral assemblages in both metabasites and pelitic rocks support the regional pattern of metamorphism indicated by illite crystallinity, and show that locally in the Tintagel district, the grade of metamorphism may have reached middle to upper greenschist facies. An attempt to correlate the above data with temperatures (108–985°C) derived from O-isotope geothermometers is made. Interpretation of the metamorphic data presented helps to emphasize the tectonic importance of the major structures seen in the fold/thrust complex.

Keywords

diagenesisgreenschist faciesilliteVariscanCornwallEngland
Type
Research Article
Information
Mineralogical Magazine , Volume 49 , Issue 352 , June 1985 , pp. 365 - 374
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1985

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.)

Footnotes

*

Present address: Department of Geology, Imperial College of Science and Technology, Prince Consort Road, London SW7 2BP.

References

Bailey, S. W. (1982) Clay Minerals, 17, 243-8.CrossRefGoogle Scholar
Brazier, S., Robinson, D., and Matthews, S. C. (1979) Neues Jahrb. Geol. Palaont. Monatsh, 641-62.Google Scholar
Coombs, D. S., Nakamura, Y., and Vuagnat, M. (1976) J. Petrol. 17, 440-71.CrossRefGoogle Scholar
Eslinger, E. V. and Savin, S. M. (1973) Am. J. Sci. 273, 240-67.CrossRefGoogle Scholar
Eslinger, E. V. and Yeh, H-S. (1979) In Aspects of Diagenesis (Scholle, P. A. and Schluger, P. R., eds.). SEPM Spec. Publ. 26, 113-24.Google Scholar
Ferry, J. M., and Spear, F. S. (1978) Contrib. Mineral. Petrol. 66, 113-17.CrossRefGoogle Scholar
Floyd, P. A. (1982) In Igneous rocks of the British Isles (Sutherland, D. S., ed.). Wiley.Google Scholar
Floyd, P. A. and Rowbotham, G. (1982) Proc. Ussher Sac. 5, 296-303.Google Scholar
Grainger, P., and Witte, G. (1981) Ibid. 5, 168-78.Google Scholar
Guidotti, C. V., and Sassi, F. P. (1976) Neues Jahrb. Mineral. Abh. 127, 97–142.Google Scholar
Hobson, D. M. (1976) Proc. Ussher Sac. 3, 320-32.Google Scholar
Hutchings, W. M. (1889) Geol. Mag. 6, 214-20.CrossRefGoogle Scholar
Johns, W. D., and Kurzweil, H. (1979) Tschermaks Mineral. Petr. Mitt. 26, 203-15.CrossRefGoogle Scholar
Kisch, H. J. (1980) J. geol. Sac. London, 137, 271-88.CrossRefGoogle Scholar
Kisch, H. J. (1983) In Diagenesis in sediments and sedimentary rocks, 2 (Larsen, G. and Chillingar, G. V., eds.). Developments in Sedimentology, 25B, Elsevier, 572 pp.Google Scholar
Liou, J. G. (1979) Am. Mineral. 64, 1–14.Google Scholar
McMurty, G. M., Wang, C-H., and Yeh, H-W. (1983) Geochim. Cosimochim. Acta, 47, 475-89.CrossRefGoogle Scholar
Matsuhia, Y., Goldsmith, J. R., and Clayton, R. N. (1979) Geochim. Cosimochim. Acta, 43, 173-82.Google Scholar
Matthews, S. C. (1977) Neues Jahrb. Geol. Palaont. Abh. 154, 94–127.Google Scholar
Milliken, K. L., Land, L. S., and Loucks, R. G. (1981) Bull. Amer. Assoc. Pet. Geol. 65, 1397-413.Google Scholar
Offler, R., Baker, C. K., and Gamble, J. (1981) Contrib. Mineral. Petrol. 76, 171-6.CrossRefGoogle Scholar
O'Neil, J. R. and Taylor, H. P. Jr. (1969) J. Geophys. Res. 74, 6012-22.CrossRefGoogle Scholar
Phillips, F. C. (1928) Geol. Mag. 65, 541-56.CrossRefGoogle Scholar
Pigage, L. C., and Greenwood, H. J. (1982) Am. J. Sci. 282, 943-69.CrossRefGoogle Scholar
Primmer, T. J. (1983) Proc. Ussher Soc. 5, 421-7.Google Scholar
Primmer, T. J. (1984) Unpubl. Ph.D. thesis, Univ. of Bristol.Google Scholar
Robinson, D., and Read, D. (1981) Proc. Ussher Sac. 5, 132-8.Google Scholar
Sanderson, D. J. (1979) J. Struct. Geol. 1, 171-80.CrossRefGoogle Scholar
Selwood, E. B., Thomas, J. M., and Stewart, I. J. (1984) Proe. Geol. Assoc. (in press).Google Scholar
Shackleton, R. M., Ries, A. C., and Coward, M. P. (1982) J. geol. Soc. London, 139, 535-43.CrossRefGoogle Scholar
Syers, J. K., Chapman, S. L., Jackson, M. L., Rex, R. W., and Clayton, R. N. (1968) Geochim. Cosimochim. Acta, 32, 1022-5.CrossRefGoogle Scholar
Taylor, H. P. Jr., and Coleman, R. G. (1968) Bull. geol. Soc. Am. 79, 1727-56.CrossRefGoogle Scholar
Tilley, C. E. (1925) Geol. Mag. 62, 314-18.Google Scholar
Velde, B. (1977) Clays and clay minerals in natural and synthetic systems. Elsevier, 218 pp.Google Scholar
Weaver, C. E. (1960) Bull. Amer. Assoc. Pet. Geol. 44, 1505-18.Google Scholar
Wenner, D. B., and Taylor, H. P. Jr. (1971) Contrib. Mineral. Petrol. 32, 165-85.CrossRefGoogle Scholar
Yeh, H-S., and Savin, S. M. (1977) Bull. geol. Soc. Am. 88, 1321-30.2.0.CO;2>CrossRefGoogle Scholar