Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-28T16:28:23.124Z Has data issue: false hasContentIssue false

The origin of granite erratics in the Pleistocene Patella beach, Gower, South Wales

Published online by Cambridge University Press:  01 May 2009

D. G. Jenkins
Affiliation:
Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK.7 6AA
R. D. Beckinsale
Affiliation:
British Geological Survey, Nicker Hill, Keyworth, Nottingham, NG12 5GG
D. Q. Bowen
Affiliation:
Department of Geography, University College of Wales, Aberystwyth, Dyfed, SY23 3DB
J. A. Evans
Affiliation:
British Geological Survey, Nicker Hill, Keyworth, Nottingham, NG12 5GG
G. T. George
Affiliation:
Department of Geology, City of London Polytechnic, 31 Jewry Street, EC3 N2EY
N. B. W. Harris
Affiliation:
Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK.7 6AA
I. G. Meighan
Affiliation:
Department of Geology, The Queen's University of Belfast, Belfast, BT7 INN

Abstract

Rare pebbles of granite have been discovered in the raised Patella beach at Butterslade, Gower, South Wales. Their petrography, trace element geochemistry and the Rb/Sr whole rock age of 55 ± 5 Ma confirm that they are derived from the Lundy granite which is about 49 km to the southwest of Gower. Amino acid analyses of fossil gastropods in the Patella beach have provided an age of 210000 years. Various hypotheses of transportation of pebbles from Lundy and Pembrokeshire to Butterslade are considered. Erratics from Pembrokeshire were probably transported by Pleistocene ice into the area while clasts of Lundy granite were moved by progradation of beach deposits northeastwards towards Gower during glacio-eustatic marine transgressions in the Pleistocene.

Type
Articles
Copyright
Copyright © Cambridge University Press 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.)

References

Andrews, J. T., Bowen, D. Q. & Kidson, C. 1979. Amino acid ratios and the correlations of raised beaches in south-west England and Wales. Nature, London 281, 556–8.CrossRefGoogle Scholar
Beckinsale, R. D., Thorpe, R. S., Pankhurst, R. J. & Evans, J. A. 1981. Rb–Sr whole rock isochron evidence for the age of the Malvern Hills Complex. Journal of the Geological Society of London 138, 6973.CrossRefGoogle Scholar
Bowen, D. Q. 1970. South-east and central South Wales. In The Glaciations of Wales and Adjoining Regions (ed. Lewis, C. A.), pp. 197227. London: Longmans.Google Scholar
Bowen, D. Q. 1973 a. The Pleistocene history of Wales and the borderland. Geological Journal 8, 207–24.CrossRefGoogle Scholar
Bowen, D. Q. 1973 b. The Pleistocene succession of the Irish Sea. Proceedings of the Geologists' Association 84, 249–72.CrossRefGoogle Scholar
Bowen, D. Q. 1974. The Quaternary of Wales. In The Upper Palaeozoic and Post-Palaeozoic Rocks of Wales (ed. Owen, T. R.), pp. 373426. University of Wales Press, Cardiff.Google Scholar
Bowen, D. Q. 1977. The coast of Wales. In The Quaternary History of the Irish sea(ed. Kidson, C. and Tooley, M. J.), pp. 223–56. Geological Journal Special Issue No. 7.Google Scholar
Bowen, D. Q. 1981. The ‘South Wales end-moraine’: fifty years after. In The Quaternary in Britain (ed. Neal, J. and Flenley, J.), pp. 60–7. Pergamon Press, Oxford.Google Scholar
Charlesworth, J. K. 1929. The South Wales end-moraine. Quarterly Journal of the Geological Society of London 85, 335–58.CrossRefGoogle Scholar
Davies, K. H. 1983. Amino acid analysis of Pleistocene marine molluscs from the Gower Peninsula. Nature, London 302, 137–9.CrossRefGoogle Scholar
Denton, G. H. & Hughes, T. J. 1981. The Last Great Ice Sheets. London: John Wiley.Google Scholar
Dollar, A. J. 1942. The Lundy Complex: its petrology and tectonics. Quarterly Journal of the Geological Society of London 97, 3977.CrossRefGoogle Scholar
George, T. N. 1932. The Quaternary beaches of Gower. Proceedings of the Geologists' Association 43, 291324.CrossRefGoogle Scholar
George, T. N. 1933. The glacial deposits of Gower. Geological Magazine 70, 208–32.CrossRefGoogle Scholar
Hails, J. R. 1975. Submarine geology, sediment distribution and Quaternary history of Start Bay Devon: Sediment distribution and Quaternary history. Journal of the Geological Society of London 131, 1935.CrossRefGoogle Scholar
Hampton, C. M. & Taylor, P. N. 1983. The age and nature of the basement of southern Britain: evidence from Sr and Pb isotopes in granites. Journal of the Geological Society of London 140, 499510.CrossRefGoogle Scholar
Meighan, I. G. 1979. The acid igneous rocks of the British Tertiary Province. Institute of Geological Sciences, Bulletin 70, 1022.Google Scholar
Miller, G. H., Brigham, J. K. & Clark, P. 1982. Alteration of the total alle/lle ratio by different methods of sample preparation. Amino acid Geochronology Laboratory Report of Current Activities 1981–1982. INSTAAR, Boulder, Colorado, 920.Google Scholar
Pankhurst, R. J. 1982. Appendix C. Geochronological tables for British Igneous rocks (The Tertiary, Table C, p. 581). In Igneous Rocks of the British Isles (ed. Sutherland, D. S.), pp. 575–81. London: John Wiley.Google Scholar
Pearce, J. A., Harris, N. B. W. & Tindle, A. G. 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology 25, 956–83.CrossRefGoogle Scholar
Shelley, D, 1966. The significance of granophyric and myrmekitic textures in the Lundy granites. Mineralogical Magazine 35, 678–92.CrossRefGoogle Scholar
Steiger, R. H. & JÄger, E. 1977. Submission on geochronology; convention on the use of decay constants in geo-and cosmochronology. Earth and Planetary Science Letters 36, 359–62.CrossRefGoogle Scholar
Sutcliffe, J. & Bowen, D. Q. 1973. Preliminary report on excavations in Minchin Hole, April–May 1973. Newsletter, William Pengelly Cave Studies Trust no. 21, 1225.Google Scholar