Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-25T05:34:59.316Z Has data issue: false hasContentIssue false
  • English
  • Français

The geochemical role of primary copper-sulphur mineralization in the crystallization of the Freetown (Sierra Leone) layered gabbro

Published online by Cambridge University Press:  05 July 2018

John F. W. Bowles
John F. W. Bowles*
Affiliation:
Institute of Geological Sciences, 64 78 Gray's Inn Road, London WC1X 8NG
Get access Rights & Permissions [Opens in a new window]

Summary

The separation of iron-titanium oxide droplets and the formation of olivine, in the Freetown layered gabbro, depleted the magma in iron and enriched the magma in copper. In magma injections in which the sulphur fugacity was sufficiently high, this resulted in the separation of immiscible copper sulphide droplets closely associated with the iron-titanium oxide droplets, and both were subsequently enclosed by olivine. A lower sulphur fugacity in other injections of magma suppressed the separation of the copper, which later appeared as native copper associated with euhedral titanomagnetite, and was enclosed by feldspar. Crystallization of the iron-titanium oxide droplets and subsolidus diffusion has resulted in granular exsolution of ilmenite from the droplets and lamellar exsolution of ilmenite in the euhedral titanomagnetite.

Type
Research Article
Information
Mineralogical Magazine , Volume 42 , Issue 321 , March 1978 , pp. 111 - 116
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1978

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

Bartholemé, (P.), 1957. Econ. Geol. 52, 895-903.[M.A. 14-145].Google Scholar
Barton, (P. B.), 1973. Ibid. 68, 455-65.[M.A. 75-1030].Google Scholar
Bowles, (J. F. W.), 1975. Rep. Inst. Geol. Sci. No. 75/9 [M.A. 76-82].Google Scholar
Bowles, (J. F. W.), 1976. Mineral. Mag. 40, 703-714.[M.A. 76-3633].CrossRefGoogle Scholar
Bowles, (J. F. W.), 1977. Ibid. 41, 103-9.[M.A. 77-2126].Google Scholar
Buddington, (A. F.) and Lindsley, (D. H.), 1964. J. Petrol. 5, 310-57.[M.A. 17-278].CrossRefGoogle Scholar
Burns, (R. G.) and Fyfe, (W. S.), 1964. Science, 144, 1001-3.CrossRefGoogle Scholar
Craig, (J. R.) and Naldrett, (A. J.), 1967. Yb. Carnegie Inst. Wash. 66, 417-19.Google Scholar
Haughton, (D. R.), Roeder, (P. L.), and Skinner, (B. J.), 1974. Econ. Geol. 69, 451-67.[M.A. 76-1567].CrossRefGoogle Scholar
Hawley, (J. E.), 1962. Canad. Mineral. 7, 1-207.[M.A. 16-413].Google Scholar
Hilty, (D. C.) and Crafts, (W.), 1952. J. Metals, 4, 1307-12.Google Scholar
Holland, (H. D.), 1959. Econ. Geol. 54, 184-233.CrossRefGoogle Scholar
Kullerud, (G.), Yund, (R. A.), and Moh, (G. H.), 1969. Econ. Geol. Monogr. 4, 323-43.[M.A. 70-2248].Google Scholar
MacLean, (W. H.), 1969. Econ. Geol. 64, 865-84.[M.A. 72-2934].CrossRefGoogle Scholar
MacLean, (W. H.) and Shimazaki, (H.), 1976. Ibid. 71, 1049-57.Google Scholar
Mason, (P. K.), Frost, (M. T.), and Reed, (S. J. B.), 1969. N.P.L. (LM.S.) Report No. 2 (unpublished).Google Scholar
Nagamori, (M.) and Kameda, (M.), 1965. Jap. Inst. Metall. Trans. 6, 21-30.CrossRefGoogle Scholar
Naldrett, (A. J.), 1969. J. Petrol. 10, 171-201.[M.A. 69-3017].CrossRefGoogle Scholar
Osborn, (E. F.), 1959. Am. J. Sci. 257, 609-47.[M.A. 14-513].CrossRefGoogle Scholar
Page (N. J.), , 1971. Econ. Geol. 66, 607-10 [M.A. 73-1652].CrossRefGoogle Scholar
Rau, (H.), 1967. J. Phys. Chem. Solids, 28, 903-16.CrossRefGoogle Scholar
Sato, (M.) and Wright, (T. L.), 1966. Science, 153, 1103-5.CrossRefGoogle Scholar
Skinner, (B. J.) and Peck, (D. L.), 1966. Econ. Geol. 61, 802 (abstr.).Google Scholar
Sato, (M.) and Wright, (T. L.) 1969. Econ. Geol. Monogr. 4, 310-22. [M.A. 70-2205].Google Scholar
Stumpfl, (E. F.), 1966. Overseas Geol. and Mineral. Res. 10, 1–10 [M.A. 18-164].Google Scholar
Umeji, (A. C.), 1975. Geol. J. 10, 107-28.CrossRefGoogle Scholar
Vogt, (J. H. L.), 1917. Norsk. Geolog. Tidsskr. 4, 151-247.Google Scholar
Vogt, (J. H. L.), 1923. Econ. Geol. 18, 307-53.CrossRefGoogle Scholar
Wager, (L. R.) and Mitchell, (R. L.), 1951. Geochim. Acta, 1, 129-208.[M.A. 11-495].CrossRefGoogle Scholar
Vincent, (E. A.), and Smales, (A. A.), 1957. Econ. Geol. 52, 855-94. [M.A. 14-145].Google Scholar
Wells, (M. K.), 1962. Geol. Surv. Dept. Sierra Leone, Short paper No. 9 (Bull. Overseas Geol. Min. Res., Suppl. No. 4) [M.A. 16-305].Google Scholar
Yazawa, (A.) and Kameda, (M.), 1954. Technol. Rep. Tohoku Univ. 19, 242.Google Scholar