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Zn-spinel in the metamorphosed Zn-Pb-Cu sulphide deposit at Mamandur, southern India

Published online by Cambridge University Press:  05 July 2018

P. K. Chattopadhyay
P. K. Chattopadhyay*
Affiliation:
Department of Geology, Jadavpur University, Calcutta-700032, India
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Abstract

At Mamandur, southern India, zincian spinel is associated with Zn-Pb-Cu sulphide ores, metamorphosed to the granulite facies. The Zn-spinel (XZn = 0.44–0.82) occurs in assemblages of: (a) cordierite + biotite + sillimanite + sphalerite + pyrite and/or pyrrhotite; (b) garnet + biotite + sphalerite + pyrite and/or pyrrhotite; (c) hornblende + biotite + sphalerite + pyrite and/or pyrrhotite; and (d) it also occurs in highly sheared quartz veins with sphalerite + pyrite/pyrrhotite. Two texturally and compositionally distinct modes of occurrence of Zn-spinel have been recorded from the metamorphic assemblages: one shows a polygonal, granular (equilibrium) fabric with Zn-spinel grains in textural equilibrium with cordierite in the granulite facies assemblage; the other which is involved in the formation of coronas in garnet- and hornblende-bearing assemblage of a younger paragenesis (presumably belonging to a late retrograde stage), shows distinct compositional zoning with depletion of Zn and enrichment in Fe and Mg from the rim inwards. A third mode of occurrence is as perfectly euhedral grains embedded in a quartzose matrix in quartz veins, often with sphalerite moulded over the Zn-spinel grains.

From textural evidence and consideration of stoichiometric balance, Zn-spinel occurring in association with cordierite is suggested to have formed by the prograde reactions: 0.46 biotite (Mg-rich) + 1.80 sillimanite + 3.01 quartz + 0.11 sphalerite = cordierite + 0.20 Zn-spinel + 0.80 K-feldspar + 0.06 pyrite + 4(OH,F) or 0.48 biotite (Mg-rich) + 2.08 sillimanite + 2.72 quartz + 0.26 sphalerite = cordierite + 0.50 Zn-spinel + 0.83 K-feldspar + 0.13 S2 + 4(OH,F) and, the Zn-spinels occurring in association with garnet and hornblende by the retrograde reactions: garnet + 4.53 Al2SiO5 + 4.17 sphalerite = 5.38 Zn (-Fe)-spinel + 0.22 Ca-feldspar + 0.92 pyrite + 7.06 quartz + 1.23 S2 and hornblende + 26.93 Al2SiO5 + 20.17 sphalerite + 0.88 pyrite = 25.93 Zn-spinel + 2 Ca-feldspar + 56.81 quartz + 11.32 S2 + 2(OH,F) Zn-spinel in the sheared quartz vein may be of (meta-) hydrothermal origin. Formation of sphalerite through sulphurization of gahnite is ruled out on the evidence of the perfectly euhedral nature of the spinel and the absence of any breakdown product from the spinel.

Keywords

Zn-spinelsulphide metamorphismgranulitesprograderetrogradeMamandurIndia
Type
Research Article
Information
Mineralogical Magazine , Volume 63 , Issue 5 , October 1999 , pp. 743 - 755
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1999

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References

Atkin, B.P., (1978) Hercynite as a breakdown product of staurolite from within the aureole of the Ardara pluton, County Donegal, Eire. Mineral. Mag., 42, 237–9.CrossRefGoogle Scholar
Bell, H. (1982) Stratabound sulfide deposits, wall-rock alteration and associated tin-bearing minerals in the Carolina state belt, South Carolina and Georgia. Econ. Geol., 77, 294–311.CrossRefGoogle Scholar
Bernier, L.R., (1990) Vanadiferous zincian-chromian hercynite in a metamorphosed basalt-hosted alteration zone, Atik Lake, Manitoba. Canad. Mineral., 28, 37–50.Google Scholar
Bristol, C.C., and Froese, E. (1989) Highly metamorphosed altered rocks associated with the Osborne lake volcanogenic massive sulfide deposit, Snow Lake area Manitoba. Canad. Mineral., 27, 593–600.Google Scholar
Chattopadhyay, P.K., (1996) High grade metamorphism and the sulphidic ores at the Mamandur area, S. Arcot, Tamil Nadu, India. Unpublished Ph.D. thesis. Jadavpur University, Calcutta, India, pp. 126–32.Google Scholar
Dasgupta, S., Sengupta, P., Guha, D. and Fukuoka, M. (1991) A refined garnet-biotite Fe-Mg exchange geothermometer and its application in amphibolites and granulites. Contrib. Mineral. Petrol., 109, 130–7.CrossRefGoogle Scholar
Ellis, D.J., and Green, D.H., (1979) An experimental study of the effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equilibria. Contrib. Mineral. Petrol., 71, 13–22.CrossRefGoogle Scholar
Ferry, J.M., and Spear, F.S., (1978) Experimental calibration of the partitioning of Fe and Mg between biotite and garnet. Contrib. Mineral. Petrol., 66, 113–7.CrossRefGoogle Scholar
Frondel, C. and Klein, C. Jr., (1965) Exsolution in franklinite. Amer. Mineral., 50, 1670–80.Google Scholar
Ganguly, J. and Saxena, S.K., (1984) Mixing properties of aluminosilicate garnets: constraints from natural and experimental data, and applications to geothermobarometry. Amer. Mineral., 69, 88–97.Google Scholar
Janardhan, A.S., Newton, R.C., and Hansen, E.C., (1982) The transition from amphibolite facies gneiss to charnockite in southern Karnataka and northern Tamil Nadu. Contrib. Mineral. Petrol., 79, 130–49.CrossRefGoogle Scholar
Lee, H.Y., and Ganguly, J. (1988) Equilibrium composition of co-existing garnet and orthopyroxene: experimental determinations in the system FeO-MgO-Al2O4-SiO2 and applications. J. Petrol., 29, 92–113.CrossRefGoogle Scholar
Moechaar, D.P., Essene, E.J., and Anovitch, L.M., (1988) Calculation and application of clinopyroxene-garnet-plagiocase-quartz geobarometers. Contrib. Mineral. Petrol. 92, 92–106.CrossRefGoogle Scholar
Moore, J.M., and Reid, A.M., (1989) A pan-African zincian staurolite imprint on Namaqua quartz-gahnite-sillimanite assemblages. Mineral. Mag., 53, 63–70.CrossRefGoogle Scholar
Nemec, D. (1973) Das Vorkommen der Zn-Spinelle in der Böhmischen Masse, TMPM Tschermaks. Min. Petr. Mitt., 19, 95–109.CrossRefGoogle Scholar
Perchuk, L.L., and Lavrent'eva, I.A., (1983) Experimental investigation of exchange equilibria in the system cordierite-garnet-biotite. In Kinetics and Equilibrium in Mineral Reactions (Saxena, S.K., ed.), Springer-Verlag, New York, pp. 199–240.CrossRefGoogle Scholar
Perkins, D. and Chipera, S.J., (1985) Garnet-ortho-pyroxene-plagioclase-quartz barometry: refinement and application to the English River Subprovince at the Minnesota river valley. Contrib. Mineral. Petrol., 89, 69–80.CrossRefGoogle Scholar
Pichamuthu, C.S., (1960) Charnockite in the making. Nature, 188, 135–6.CrossRefGoogle Scholar
Sangster, D.F., and Scott, S.D., (1976) Precambrian massive Cu-Zn-Pb sulfide ores of North America. In Handbook of Strata-bound and Stratiform Ore Deposits (Wolf, K.H., ed.), Elsevier, Amsterdam, 6, pp. 129–222.Google Scholar
Sheridan, D.M., and Raymond, W.H., (1984) Precambrian deposits of zinc-copper-lead sulfides and zinc spinel (gahnite) in Colorado. US Geol. Surv. Bull., 1550, 31 pp.Google Scholar
Spear, F.S., (1991) On the interpretation of peak metamorphic temperatures in light of garnet diffusion during cooling. J. metam. Geol., 9, 379–88.CrossRefGoogle Scholar
Spry, P.G., (1984) The synthesis stability, origin and exploration, significance of zincian spinels. Unpublished Ph.D. Thesis, Univ. Toronto, Ontario, Canada.Google Scholar
Spry, P.G., (1987 a) Compositional zoning in zincian spinel. Canad. Mineral., 25, 97–104.Google Scholar
Spry, P.G., (1987 b) The chemistry and origin or zincian spinel associated with Aggeneys Cu-Pb-Zn-Ag deposits, Namaqualand, South Africa. Mineral. Deposita, 22, 262–8.CrossRefGoogle Scholar
Spry, P. and Scott, S.D., (1986 a) Zincian spinel and staurolite as guides to ore in the Appalachians and Scandanavian Caledonides. Canad. Mineral., 24, 147–63.Google Scholar
Spry, P. and Scott, S.D., (1986 b) 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
Thompson, A.B., (1976) Mineral reaction in pelitic rocks: II Calculation of some P-T-X (Fe-Mg) phase relations. Amer. J. Sci., 282, 1567–95.CrossRefGoogle Scholar
Tulloch, A.J., (1981) Gahnite and columbite in an alkali- feldspar granite from New Zealand. Mineral. Mag., 44, 275–8.CrossRefGoogle Scholar
Wall, V.J., and England, R.N., (1979) Zn-Fe spinel-silicate-sulfide reactions as sensors of metamorphic intensive variables and processes. Geol. Soc. Amer. Abstracts with Program, V.11, p. 354.Google Scholar
Zaleski, E., Froese, E. and Gordon, T.M., (1991) Metamorphic petrology of Fe-Zn-Mg-Al alteration at the Linda volcanogenic Massive sulfide deposit, Snow Lake, Manitoba. Canad. Mineral., 29, 995–1017.Google Scholar