Closed system fractionation in a large magma chamber: Mineral compositions of the websterite layer and lower mafic succession of the Great Dyke, Zimbabwe

Mineralogical Magazine

Volumn 61, Issue 2, 1997, Pages 153-173

  Wilson, A H ^a   Chaumba, J B ^a,b  

^a UNIVERSITY OF KWAZULU NATAL   (South Africa)

^b UNIVERSITY OF CAPE TOWN   (South Africa)

Author keywords

Closed system fractionation; Great Dyke; Lower Mafic Succession; Websterite; Zimbabwe

Indexed keywords

FRACTIONATION; MAFIC ROCK; MAGMA CHAMBER; WEBSTERITE;

ZIMBABWE, GREAT DYKE;

EID: 0030987705     PISSN: 0026461X     EISSN: None     Source Type: Journal    
DOI: 10.1180/minmag.1997.061.405.01     Document Type: Article

References (52)

1. Ashwal, L.D. (1995) Trace element geochemistry of Bushveld plagioclase. Centenial Geocongress Extended Abstracts. Johannesburg: Geological Society of South Africa. 492-3.
2. Atkins, F.B. (1969) Pyroxenes of the Bushveld intrusion, South Africa. J. Petrol., 10, 222-49.
3. Barnes, S.J. (1986a) The effect of trapped liquid crystallization on cumulus mineral compositions in layered intrusions. Contrib. Mineral. Petrol., 93, 524-31.
4. Barnes, S.J. (1986b) The distribution of chromium among orthopyroxene, spinel and silicate liquid at atmospheric pressure. Geochim. Cosmochim. Acta, 50, 1889-909.
5. Beattie, P. (1993) Olivine-melt and orthopyroxene-melt equilibria. Contrib. Mineral. Petrol., 115, 103-11.
6. Beattie, P., Ford, C. and Russell, D. (1991) Partition coefficients for olivine-melt and orthopyroxene-melt systems. Contrib. Mineral. Petrol., 109, 212-24.
7. Boudreau, A. E. (1987) Pattern formation during crystallization and the formation of fine-scale layering. In: I. Parsons, (ed.) Origin of Igneous Layering. NATO ASI Series. Dordrecht: D. Reidel, 287-312.
8. Boyd, F.R. and England, J.L. (1964) The system enstatite-pyrope. Carnegie Inst. Washington, Ann. Rept. Dir. Geophys. Lab., 1963-64. 157-61.
9. Brown, G.M. (1957) Pyroxenes from the early and middle stages of fractionation of the Skaergaard intrusion, East Greenland. Mineral. Mag., 31, 511-43.
10. Cameron, M. and Papike, J.J. (1981) Structural and chemical variation in pyroxenes. Amer. Mineral., 66, 1-50.
11. Campbell, I.H. (1987) Distribution of orthocumulate textures in the Jimberlana intrusion. J. Geol., 95, 35-54.
12. Campbell, I.H. and Borley, G.D. (1974) The geochemistry of pyroxenes from the lower layered series of the Jimberlana intrusion, Western Australia. Contrib. Mineral. Petrol., 47, 281-97.
13. Eales, H.V., Teigler, B. and Maier, W.D. (1993) Cryptic variations of minor elements Al, Cr, Ti and Mn in Lower and Critical Zone orthopyroxenes of the western Bushveld Complex. Mineral. Mag., 57, 257-64.
14. 3 in enstatite coexisting with forsterite and spinel. Carnegie Inst. Washington, Ann. Kept. Dir. Geophys. Lab., 1975-76, 566-71.
15. Green, T.H. (1994) Experimental studies of trace-element partitioning applicable to igneous petrogenesis - Sedena 16 years later. Chem. Geol., 117, 1 -36.
16. Hamilton, J. (1977) Sr isotope and trace element studies of the Great Dyke and Bushveld mafic phase and their relation to early Proterozoic magma genesis in southern Africa. J. Petrol., 18, 24-52.
17. Hanghoj, K., Rosing, M.T. and Brooks, C.K. (1995) Evolution of the Skaergaard magma: evidence from crystallized melt inclusions. Contrib. Mineral. Petrol., 120, 265-9.
18. Hart, S.R. and Dunn, T. (1993) Experimental cpx/melt partitioning of 24 trace elements. Contrib. Mineral. Petrol., 113, 1-8.
19. Hatton, C.J. and von Gruenewaldt, G. (1985) Chromite from the Swartkop Chrome Mine - an estimate of the effects of subsolidus reequilibration. Econ. Geol., 80, 911-24.
20. Henderson, P. (1970) The distribution of phosphorus in the early and middle stages of fractionation of some basic layered intrusions. Geochim. Cosmochim. Acta, 32, 897-911.
21. Hunter, R.H. and McKenzie, D.P. (1989) Compaction and textural equilibration in layered intrusions. 28th Int. Geol. Cong., Abstracts, 2, 284.
22. Hunter, R.H. and Sparks, R.S.J. (1987) The differentiation of the Skaergaard Intrusion. Contrib. Mineral. Petrol., 95, 451-61.
23. Hunter, R.H. and Sparks, R.S.J. (1990) The differentiation of the Skaergaard Intrusion: a discussion. Contrib. Mineral. Petrol., 104, 248-54.
24. Irvine, T.N. (1980) Magmatic infiltration metasomatism, double diffusive fractional crystallization and adcumulus growth in the Muskox intrusion and other layered intrusions. In: R.B. Hargraves, (ed.) Physics of Magmatic Processes. Princeton: Princeton Univ., 325-83.
25. Irvine, T.N., Keith, D.W. and Todd, S.G. (1983) The J-M platinum-palladium reef of the Stillwater Complex, Montana: II. Origin by double-diffusive convective magma mixing and implications for the Bushveld Complex. Econ. Geol., 78, 1287-334.
26. Kruger, F.J. and Marsh, J.S. (1985) Significance of Sr87/Sr86 ratios in the Merensky cyclic unit of the Bushveld Complex. Nature, 298, 53-55.
27. Lindsley, D.H. and Dixon., S.A. (1976) Diopside-enstatite equilibria at 850°C to 1400°C, 5 to 35 kb. Amer. J. Sci., 276, 1285-301.
28. McBirney, A.R. and Naslund, H.L. (1990) The differentiation of the Skaergaard Intrusion: a discussion. Contrib. Mineral. Petrol., 104, 235-40.
29. Meurer, W.P and Boudreau, A.E. (1996) Compaction of density-stratified cumulates: effect on trapped-liquid distribution. J. Geol., 104, 115-20.
30. McKenzie, D.P. (1984) The generation and compaction of partially molten rock. J. Geol., 25, 713-65.
31. Mitchell, A.A. (1990) The stratigraphy and mineralogy of the Main Zone of the northwestern Bushveld Complex. S. Afr. J. Geol., 93, 818-31.
32. Mysen, B.O. and Boettcher, A.L. (1975). Melting of hydrous mantle: II. Geochemistry of crystals and liquids by anatexis of mantle peridotite at high pressures and high temperatures as a function of controlled activities of water, hydrogen and carbon dioxide. J. Petrol., 16, 549-93.
33. Nathan, H.D. and Van Kirk, C.K. (1978) A modal of magmatic crystallization. J. Petrol., 19, 66-94.
34. Podmore, F. and Wilson, A.H. (1987) A reappraisal of the structure, geology and emplacement of the Great Dyke, Zimbabwe. In: H.C. Halls & W.F. Fahrig, (eds.) Mafic Dyke Swarms. Geol. Assoc. Canada Spec. Paper 34, 317-30.
35. Prendergast, M.D. (1987) The chromite ore field of the Great Dyke, Zimbabwe. In: C.W. Stowe, (ed.) Evolution of Chromium Ore Fields. New York: Van Nostrand Reinhold, 89-108.
36. Prendergast, M.D. (1988) The geology and economic potential of the PGE rich Main Sulphide Zone of the Great Dyke, Zimbabwe. In: H.M. Pritchard, P.J. Potts, J.F.W. Bowles and S.J. Cribb, (eds.) CeoPlatinum 87. London: Elsevier, 281-302.
37. Prendergast, M.D. and Keays, R.R. (1989) Controls of platinum-group element mineralization of the PGE-rich Main Sulphide Zone in the Wedza Subchamber of the Great Dyke, Zimbabwe: implications for the genesis of, and exploration for, stratiform PGE mineralization in layered intrusions. In: M.D. Prendergast and M. Jones, (eds.) 5th Magmatic Sulphides Field Conference, Harare, Zimbabwe. London: Institution of Mining and Metallurgy, 43-69.
38. Prendergast, M.D. and Wilson, A.M. (1989) The Great Dyke of Zimbabwe. II Mineralization and mineral deposits. In: M.D. Prendergast and M. Jones, (eds.) 5th Magmatic Sulphides Field Conference, Harare, Zimbabwe. London: Institution of Mining and Metallurgy, 21-42.
39. Roeder, P.L. and Emslie, R.F. (1970) Olivine-liquid melt equilibrium. Contrib. Mineral. Petrol., 29, 275-89.
40. Rollinson, H. (1993) Using geochemical data: Evaluation, Presentation, Interpretation. New York: Longman Scientific and Technical. 352 pp.
41. Saxena, S.K. (1968) Distribution of elements between coexisting minerals and the nature of solution in garnet. Amer. Mineral., 53, 994-1014.
42. Sharpe, M.R. (1985) Strontium isotopic evidence for preserved density stratification from the Main Zone of the Bushveld Complex, South Africa. Nature, 316, 119-26.
43. Shirley, D.N. (1986) Compaction of igneous cumulates. J. Geol., 94, 795-809.
44. Sparks, R.S.J., Huppert, H.E, Kerr, R.C., McKenzie, D.P. and Tait, S.R. (1985) Postcumulus processes in layered intrusions. Geol. Mag., 122, 555-68.
45. Wager, L.R. (1960) The major element variation of the layered series of the Skaergaard intrusion and a reestimation of the average compositions of the hidden layered series and of the successive residual magmas. J. Petrol., 1, 364-98.
46. Wager, L.R. (1963) The mechanism of adcumulus growth in the layered series of the Skaergaard intrusion. Mineral. Soc. Amer. Spec. Paper, 1, 1-19.
47. Wilson, A.H. (1982) The geology of the Great Dyke, Zimbabwe: The ultramafic rocks. J. Petrol., 23, 240-92.
48. Wilson, A.M. (1992) The geology of the Great Dyke, Zimbabwe: Crystallization, layering, and cumulate formation in the P1 pyroxenite of Cyclic Unit 1 of the Darwendale Subchamber. J. Petrol., 33, 611-663.
49. Wilson, A.H. and Prendergast, M.D. (1989) The Great Dyke of Zimbabwe. I: Tectonic setting, stratigraphy, petrology, structure, emplacement and crystallization. In: M.D. Prendergast and M. Jones, (eds.) 5th Magmatic Sulphides Field Conference, Harare, Zimbabwe. London: Institution of Mining and Metallurgy, 1-20.
50. Wilson, A.M. and Tredoux, M. (1990) Lateral and vertical distribution of the platinum-group elements and petrogenetic controls on the sulfide mineralization in the P1 pyroxenite layer of the Darwendale Subchamber of the Great Dyke, Zimbabwe. Econ. Geol., 85, 556-84.
51. Wilson, A.H. and Wilson, J.F. (1981) The Great 'Dyke'. In: D.R. Hunter, (ed.) Precambrian of the Southern Hemisphere. Amsterdam: Elsevier, 572-8.
52. Wilson, A.M., Naldrett, A.J. and Tredoux, M. (1989) Distribution and controls of platinum-group element and base metal mineralization in the Darwendale Subchamber of the Great Dyke, Zimbabwe, Geology, 17, 649-52.