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Ages of uraninite and Coffinite from south-west England

Published online by Cambridge University Press:  14 March 2018

A. G. Darnley
Affiliation:
Atomic Energy Division, Geological Survey of Great Britain
T. H. English
Affiliation:
National Chemical Laboratory, Teddington, Middlesex
O. Sprake
Affiliation:
National Chemical Laboratory, Teddington, Middlesex
E. R. Preece
Affiliation:
Atomic Energy Research Establishment, Harwell, Berkshire
D. Avery
Affiliation:
Atomic Energy Research Establishment, Harwell, Berkshire

Summary

The mode of occurrence of uraninite, pitchblende and coffinite at five localities in south-west England is described. Chemical and isotopic analyses of concentrates containing these minerals provide the following 206Pb/238U ages (My.): uraninite, South Crofty, Cornwall, 277 ± 10; uraninite, Geevor, Cornwall, 223 ± 5; pitcbblende-coffinite, King's Wood, Devon, 206 ± 5; pitchblende, Wheal Bray, Cornwall, 165 ± 4; pitchblende, South Terras, Cornwall, 474 ± 2; coffinite, Geevor, Cornwall, c. 45 (chemical analysis only). These results are compatible with geological and mineralogical evidence. Consideration of these and other results indicates that there were at least three periods of uranium mineralization in south-west England, at c. 290 My., c. 225 My., and c. 50 My. Other intermediate ages may also be valid but further work is required to substantiate these.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1965

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References

Beer, (K. E.), 1958. Investigations it Wheal Bray, Altarnun, Cornwall. Report No. 202, Atomic Energy Division, Geol. Surv. Gt. Brit. (unpublished).Google Scholar
Campbell, (C.B.), 1947. Geological and radiometrie report on King's Wood Mine. Report No. 20, Atomic Energy Division, Geol. Surv. Gt. Brit. (unpublished).Google Scholar
Collins, (J.H.), 1896. J. roy. Instn. Cornwall, vol. 13, p. 283.Google Scholar
Darnley, (A.G.), Chandler (T.R . D.), E:Nglish, (T.H.), Fidlfr(P. A.), James, (O.), Peece, (E.R.), and Prosser (N. J. D.), 1962. Pitchblende from Sandyhills, Kircudbrightshire. Age Determination Report No. 20. Atomic Energy Division, Geol. Surv. Gt. Brit. (unpublished).Google Scholar
Darnley, (A.G.), Smith, (G.H.), Chandler (T. R. D.), Dance, (D.F.), Preece, (E.R.), 1960. Min. Mag., vol. 32, p. 654.Google Scholar
De la Bache, (H.T.), 1839. Report on the geology of Cornwall, Devon, and West Somerset. Mem. geol. Surv. Gt. Brit.Google Scholar
Deutsch, (S.), and Chauris, (L.), 1960. C. R. Aead. Sei., Paris, vol. 250, p. 1298.Google Scholar
Dines, (H.G.), 1956. Metalliferous Mining Region of South-West England. Mere. geol. Surv. Gt. Brit.Google Scholar
Dodson, (M.H.), Miller, (J.A.), and York, (D.), 1961. Nature, Lond., vol. 190, p. 800.Google Scholar
Dodson, (M.H.), and Lona, (L.E.), 1962. Ibid., vol. 195, p. 975.Google Scholar
Frondel, (C.), 1958. Systematic Mineralogy of Uranium and Thorium. Bull. U.S. geol. Surv. 1064.Google Scholar
Gannett, (R. H. T.), 1963. Polyaseendent Zoning in the No. 3 Branch Lode of Geevor Tin Miae, Cornwall. Symposium Problems of Postmagmatie Ore Deposition, vol. 1, p. 97. Prague.Google Scholar
Hill, (J.B.), 1901. Trans. R. geol. Soc., Cornwall., vol. 16, p. 279.Google Scholar
Lambert, (R. ST. J.), and Mills, (A.A.), 1961. Ann. N.Y. Acad. Sei., vol. 91, art. 2, p. 378.Google Scholar
Mcalister, (D.A.), 1906. In Geology of Fahnouth and Truro and of the Mining District of Camborne and Redruth. Mere. geol. Surv. Gt. Brit.Google Scholar
Miller, (J.A.), and Fitch, (F.J.), 1962. Nature, Lond., vol. 195, p. 553.CrossRefGoogle Scholar
Moorbath, (S.), 1962. Phil. Trans., See. A, vol. 254, p. 295.Google Scholar
Ostle, (D.), and Cosgrove, (M.E.), 1953. The South Terras Uranimn Mine, Cornwall. Report No. 138, Atomic Energy Division, Geol. Surv. Gt. Brit, (unpublished).Google Scholar
Pockley, (R. P. C.), 1961. Lead Model Age Tables. Dept. of Geology and Mineralogy, Oxford University (cyclostyled edition).Google Scholar
Pockley, (R. P. C.), 1964. Four New Uraniam-lead Ages from Cornwall. Min. Mag, (in press).Google Scholar
Stieff, (L.R.), Stern (T, W.), Oshiro, (S.), and Sentftle, (F.E.), 1959. Prof. Pap. U.S. geol. Surv. 334-A.Google Scholar
Wetherill, (G.W.), 1956. Trans. Amer. geophys. Un., vol. 37, p. 320.Google Scholar
Wickman, (F.E.), 1944. Arsb. Sverig. geol. Unders., vol. 37 (1943), p. 3.Google Scholar