Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-04T22:01:19.274Z Has data issue: false hasContentIssue false
  • English
  • Français

A Pan-African zincian staurolite imprint on Namaqua quartz–gahnite–sillimanite assemblages

Published online by Cambridge University Press:  05 July 2018

J. M. Moore  and
A. M. Reid
J. M. Moore
Affiliation:
Geology Department, University of Cape Town, Private Bag, Rondebosch 7700, South Africa
A. M. Reid
Affiliation:
Geology Department, University of Cape Town, Private Bag, Rondebosch 7700, South Africa
Get access Rights & Permissions [Opens in a new window]

Abstract

Quartz-gahnite-sillimanite asssemblages are described from a supracrustal enclave at Kraaifontein, 45 km south-west of Springbok in the Namaqualand Metamorphic Complex, South Africa. The assemblage formed by prograde reaction in the granulite facies zone during the 1100 Ma Namaqua event, possibly as the result of desulphidation of sphalerite. Subsequent lower-amphibolite-facies retrogression occurred in close proximity to shear zones during an early Pan-African metamorphic event at 700 Ma. Zincian staurolite formed as overgrowths on gahnite in a hydration reaction involving the consumption of gahnite, quartz, and sillimanite. Compositional zoning to more zinc-rich rims in gahnite at Kraaifontein is unrelated to the retrograde reaction, but is interpreted as a result of changing conditions during the prograde Namaqua event.

Keywords

zincstaurolitegahniteKraaifonteinNamaqualand Metamorphic Complex
Type
Petrology and Geochemistry
Information
Mineralogical Magazine , Volume 53 , Issue 369 , March 1989 , pp. 63 - 70
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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.)

Footnotes

*

Present address: Department of Geosciences, University of Houston, 4800 Calhoun Road, Houston, Texas 77004, U.S.A.

References

Albee, A. L. (1972) Metamorphism of pelitic schists: reaction relations of chloritoid and staurolite. Bull, Geol. Soc. Am. 83, 3249-68.CrossRefGoogle Scholar
Allsop, H. L., Köstlin, E. O., Welke, H. J., Burger, A. J., Krrner, A., and Blignault, H. J. (1979) Rb-Sr and U Pb geochronology of Late Precambrian-Early Palaeozoic igneous activity in the Richtersveld (South Africa) and southern South West Africa. Trans. Geol. Soe. S. Aft. 82, 185-204.Google Scholar
Ashworth, J. R. (1975) Staurolite at anomalously high grade. Contrib. Mineral. Petrol. 53, 281-91.CrossRefGoogle Scholar
Atkin, B. P. (1978) Hercynite as a breakdown product of staurolite from within the aureole of the Ardara Pluton, Co. Donegal, Eire. Mineral. Mag. 42, 237-9.CrossRefGoogle Scholar
Chinner, G. A. (1965) The kyanite isograd in Glen Cova, Angus, Scotland. Ibid. 34, 316-40.Google Scholar
Clifford, T. N., Gronow, J., Rex, D. C., and Burger, A. J. (1975) Geochronological and petrogenetic studies of high grade metamorphic rocks and intrusives in Namaqualand, South Africa. J. Geol. 16, 154-88.Google Scholar
Cumming, B. (1975) The geology of the farm Kraaifontein near Komaggas, Namaqualand. Unpubl. BSc(Hons) project, Univ. Cape Town, 18 pp.Google Scholar
Frost, R. B. (1973) Ferroan gahnite from quartz-biotite-almandine schist, Wind River Mountains, Wyoming. Am. Mineral. 58, 831-4.Google Scholar
Griffen, D. T. (1981) Synthetic Fe/Zn staurolites and the ionic radius of ivZn2+. Ibid. 67, 932-7.Google Scholar
Griffen, D. T. and Ribbe, P. H. (1973) The crystal chemistry of staurolite. Am. J. Sci. 273-A, 479-95.Google Scholar
Guidotti, C. V. (1970) The mineralogy and petrology of the transition from the lower to upper sillimanite zone in the Oquossoc area, Maine. J. Petrol. 11, 277-336.CrossRefGoogle Scholar
Hicks, J. A., Moore, J. M., and Reid, A. M. (1985) The co-occurrence of green and blue gahnite in the Namaqualand Metamorphic Complex, South Africa. Can. Mineral. 23, 535-42.Google Scholar
Holdaway, M. J., Dutrow, B. L., Borthwick, J., Shore, P., Harmon, R. S., and Hinton, R. W. (1986a) H content of staurolite as determined by H extraction line and ion microprobe. Am. Mineral. 71, 1135-41.Google Scholar
Holdaway, M. J., Dutrow, B. L., Borthwick, J., Shore, P., Harmon, R. S., and Hinton, R. W. and Shore, P. (1986b) A model for the crystal chemistry of staurolite. Ibid. 71, 1142-59.Google Scholar
Hoschek, G. (1969) The stability of staurolite and chloritoid and their significance in metamorphism of pelitic rocks. Contrib. Mineral. Petrol. 22, 208-32.CrossRefGoogle Scholar
Jack, A. M. (1980) The geology of western Namaqualand. Precambr. Res. Unit, Univ. Cape Town, Bull. 29, 173 pp.Google Scholar
Jackson, M. P. A., and Zelt, G. A. D. (1984) Proterozoic crustal reworking and superposed deformation of metabasite dykes, layered intrusions, and lavas in Namaqualand, South Africa. In Preeambrian Tectonics Illustrated (Krrner, A. and Greiling, R., eds.). E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, 381-400.Google Scholar
Joubert, P. (1971) The regional tectonism of the gneisses of part of Namaqualand. Precambr. Res. Unit, Univ. Cape Town, Bull. 10, 220 pp.Google Scholar
Joubert, P. and Waters, D. J. (1980) The occurrence of kyanite at Zoutpan and metamorphism in western Namaqualand. Precambr. Res. Unit, Univ. Cape Town, Ann. Rep. 17, 74-87.Google Scholar
Kramm, U. (1977) Gahnite of the Venn-Stavelot Massif and its petrologic significance. Ann. Soc. Geol. Belg. 100, 199-201.Google Scholar
Lonker, S. W. (1983) The hydroxyl content of staurolite. Contrib. Mineral. Petrol. 84, 36-42.CrossRefGoogle Scholar
Miyake, A. (1985) Zn-rich staurolite from the Uvete area, central Kenya. Mineral. Mag. 49, 573-8.CrossRefGoogle Scholar
Moore, J. M. (1977) The geology of the Namiesberg, northern Cape. Preeambr. Res. Unit, Univ. Cape Town, Bull. 20, 69 pp.Google Scholar
Moore, J. M. (1986) A comparative study of metamorphosed supracrustal rocks from the western Namaqualand Metamorphic Complex. Unpubl. Ph.D. thesis, Univ. Cape Town, 370 pp.Google Scholar
Moore, J. M. and Reid, A. M. (1988) Implications of sphalerite inclusions in gahnite from the Namaqualand Metamorphic Complex, South Africa. Can. Mineral. 26, 293-300.Google Scholar
Neumann, H. (1949) Notes on the mineralogy and geochemistry of zinc. Mineral. Mag. 28, 575-81.Google Scholar
Ribbe, P. H. (1982) Staurolite. In Orthosilicates (Ribbe, P. H., ed.). Mineral. Soc. Am. Reviews in Mineralogy, 5, 171-88.CrossRefGoogle Scholar
Schumacher, R. (1985) Zincian staurolite in Glen Doll, Scotland. Mineral. Mag. 49, 561-71.CrossRefGoogle Scholar
Spry, P. G. (1987a) Compositional zoning in zincian spinel. Can. Mineral. 25, 97-104.Google Scholar
Spry, P. G. (1987b) The chemistry and origin of zincian spinel associated with the Aggeneys Cu-Pb Zn-Ag deposits, Namaqualand, South Africa. Mineral. Deposita, 22, 262-8.Google Scholar
Spry, P. G. and Scott, S. D. (1986a) Zincian spinel and staurolite as guides to ore in the Appalachians and Scandinavian Caledonides. Can. Mineral. 24, 147-63.Google Scholar
Spry, P. G. and Scott, S. D. (1986b) The stability of zincian spinels in sulfide systems and their potential as exploration guides for metamorphosed massive sulfide deposits. Econ. Geol. 81, 1446-63.CrossRefGoogle Scholar
Stoddard, E. F. (1979) Zinc-rich hercynite in high-grade metamorphic rocks: a product of the dehydration of staurolite. Am. Mineral. 64, 736-41.Google Scholar
Theart, H. F. J. (1980) The geology of the Precambrian terrane in parts of western Namaqualand. Precambr. Res. Unit, Univ. Cape Town, Bull. 30, 103 pp.Google Scholar
Tuisku, P., Ruostesuo, P., and Hakkinen, A-M., (1987) The metamorphic behaviour and petrogenetic significance of zinc in amphibolite facies, staurolite-bearing mica schists, Puolankajarvi Formation, Central Finland. Geochim. Cosmochim. Acta, 51, 1639-50.CrossRefGoogle Scholar
Ward, J. H. W. (1977) The geology of the area south of Vioolsdrif, Cape Province. Atomic Energy Board, Pretoria, Rep. PEL-257, 48 pp.Google Scholar
Waters, D. J. (1986) Metamorphic zonation and thermal history of pelitic gneisses from western Namaqualand, South Africa. Trans. Geol. Soe. S. Afr. 89, 97-102.Google Scholar
Waters, D. J. Joubert, P., and Moore, J. M. (1983) A suggested reinterpretation of Namaqua basement and cover rocks south and west of Bitterfontein. Ibid. 86, 293-9.Google Scholar
Yardley, B. W. D. (1981) A note on the composition and stability of Fe-staurolite. Neues Jahrb. Mineral. Mh. 127-32.Google Scholar