Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-20T17:22:34.687Z Has data issue: false hasContentIssue false
  • English
  • Français

The use of phosphorus contents in yielding estimates of the proportion of trapped liquid in cumulates of the Upper Zone of the Bushveld Complex

Published online by Cambridge University Press:  05 July 2018

R. Grant Cawthorn  and
Kevin L. Walsh
R. Grant Cawthorn
Affiliation:
Department of Geology, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2001, South Africa
Kevin L. Walsh
Affiliation:
Department of Geology, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2001, South Africa
Get access Rights & Permissions [Opens in a new window]

Abstract

Phosphorus contents in cumulus rocks occurring close to the level of apatite appearance in the basic rocks of the Bushveld Complex, South Africa, provide a method of calculating the proportion of intercumulus component in these rocks. Previous experimental studies have accurately constrained the phosphorus content of magmas when apatite becomes stable. The ratio of the phosphorus content in the cumulates immediately below the appearance of apatite to this liquid composition defines the proportion of trapped liquid.

Application of this method to rocks from the uppermost mafic rocks of the Bushveld Complex leads to the conclusion that there is from 1 to 6 per cent intercumulus component. Many of these rocks are multiphase cumulates and in such rocks estimation of intercumulus component from textural criteria is difficult.

If crystals grow In situ on the floor of the magma chamber such small proportions of interstitial component can be produced without appealing to excessive diffusion and circulation of magma through an unconsolidated crystal pile. The geometry of the intrusion as well as its size might have a major influence on the proportion of the liquid ultimately solidifying within a cumulus rock.

Keywords

layered complexesintercumulusapatitebottom growth
Type
Geochemistry
Information
Mineralogical Magazine , Volume 52 , Issue 364 , March 1988 , pp. 81 - 89
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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

Abbey, S. (1983) Geol. Surv. Canada, Paper 83–15.Google Scholar
Bowen, N.L. (1927) Amer. J. Sci. 14, 89–108.CrossRefGoogle Scholar
Brooks, C.K., and Nielsen, T.F. D. (1978) Lithos, 11, 114.CrossRefGoogle Scholar
Cameron, E.N. (1975) Geochim. Cosmochim. Acta, 39, 102-13.Google Scholar
Campbell, I.H. (1978) Lithos, 11, 311-23.CrossRefGoogle Scholar
Campbell, I.H. Roeder, P.L., and Dixon, J.M. (1978) Contrib. Mineral. Petrol. 67, 369–77.CrossRefGoogle Scholar
Cawthorn, R.G. (1977) Trans. Geol. Soc. S. Afr. 80, 139–44.Google Scholar
Cawthorn, R.G. and McCarthy, T.S. (1980) Earth Planet. Sci. Lett. 46, 335–43.CrossRefGoogle Scholar
Cawthorn, R.G. (1985) Econ. Geol. 80, 101-62.Google Scholar
Coertze, F.J. (1970) Geol. Soc. S. Aft., Spec. Publ. 1, 5–22.Google Scholar
Cox, K.G. (1980) J. Petrol. 21, 629–50.CrossRefGoogle Scholar
Czamanske, G.K., and Scheidle, D.L. (1985) Montana Bureau Mines Geol., Spec. Publ. 92, 334–45.Google Scholar
Davies, G., and Cawthorn, R.G. (1984) Mineral. Mag. 48, 469-80.CrossRefGoogle Scholar
Green, T.H., and Watson, E.B. (1982) Contrib. Mineral. Petrol. 79, 961-05.Google Scholar
Harrison, T.M., and Watson, E.B. (1984) Geoehim. Cosmochim. Acta, 48, 1467–77.CrossRefGoogle Scholar
Hatton, C.J., and yon Gruenewaldt, G. (1985) Econ. Geol. 80, 911–24.CrossRefGoogle Scholar
Henderson, P. (1968) Geoehim. Cosmochim. Acta, 32, 897-91.CrossRefGoogle Scholar
Henderson, P. (1970) J. Petrol. 11, 463–73.CrossRefGoogle Scholar
Henderson, P. (1975) Mineral. Mag. 40, 285-91.CrossRefGoogle Scholar
Hess, H.H. (1939) Trans. Am. Geophys. Union, 430–2.CrossRefGoogle Scholar
Himmelberg, G.R., and Loney, R.A. (1981) U.S. Geol. Surv. Prof. Pap. 1195, 24 pp.Google Scholar
Irvine, T.N. (1982) J. Petrol. 23, 127–62.CrossRefGoogle Scholar
Keith, D.W., and Todd, S.G. (1983) Econ. Geol. 78, 1287–334.Google Scholar
Lindsley, D.H., Brown, G.M., and Muir, E.D. (1969) Mineral. Soc. Am. Spec. Pap. No. 2, 193–201.Google Scholar
Markgraaff, J. (1976) Trans. Geol. Soc. S. Aft. 79, 217–24.Google Scholar
McBirney, A.R. (1980) J. Volcanol. Geotherm. Res. 7, 357–71.CrossRefGoogle Scholar
McBirney, A.R. and Noyes, R.M. (1979) J. Petrol. 20, 487–554.CrossRefGoogle Scholar
McKenzie, D.P. (1984) Ibid. 25, 713-65.Google Scholar
Molyneux, T.G. (1974) Trans. Geol. Soe. S. Aft. 77, 329–38.Google Scholar
Norrish, K. and Hutton, J.T. (1969) Geochim. Cosmochirn. Acta, 33, 431–53.CrossRefGoogle Scholar
Osborn, E.F. (1979) In The Evolution of Igneous Rocks (H. S. Yoder, Jr., ed.) Princeton Univ. Press, Princeton, New Jersey: 133–70.Google Scholar
Reynolds, I.M. (1985) Econ. Geol. 80, 1027–48.CrossRefGoogle Scholar
Sparks, R.S. J., Huppert, H.E., and Turner, J.S. (1984) Phil. Trans. Roy. Soc. London , A130, 51134.Google Scholar
Sparks, R.S. J., Huppert, H.E., and Turner, J.S. Kerr, R.C., McKenzie, D.P., and Tait, S.R. (1985) Geol. Mag. 122, 555–68.CrossRefGoogle Scholar
Thompson, R.N. (1972) Am. J. Sci. 272, 901–32.CrossRefGoogle Scholar
yon Gruenewaldt, G. (1973) Trans. Geol. Soc. S. Afr. 76, 207–27.Google Scholar
Sharpe, M.R., and Hatton, C.J. (1985) Econ. Geol. 80, 803–12.CrossRefGoogle Scholar
Wager, L.R. (1960) J. Petrol. 1, 364–98.CrossRefGoogle Scholar
Wager, L.R. and Brown, G.M. (1968) Layered lgneous Rocks , Oliver and Boyd, Edinburgh, 588 pp.Google Scholar
Wager, L.R. and Deer, W.A. (1939) Medd. Grrnland , 105. Google Scholar
Wager, L.R. Brown, G.M., and Wadsworth, W.J. (1960) J. Petrol. 1, 73–85.CrossRefGoogle Scholar
Walraven, F. and Wolmarans, L.G. (1979) Annals Geol. Surv. S. Afr. 13, 109–14.Google Scholar
Watson, E.B. and Capobianco, C.J. (1981) Geoehim. Cosmochim. Aeta, 45, 234-95.Google Scholar
Watson, E.B. and Capobianco, C.J. and Green, T.H. (1981) Earth Planet. Sci. Lett. 56, 405–21.CrossRefGoogle Scholar