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Hibonite and coexisting zoisite and clinozoisite in a calc-silicate granulite from southern Tanzania

Published online by Cambridge University Press:  05 July 2018

P. Maaskant ,
J. J. M. M. M. Coolen  and
E. A. J. Burke
P. Maaskant
Affiliation:
Institute of Earth Sciences, Free University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
J. J. M. M. M. Coolen
Affiliation:
Institute of Earth Sciences, Free University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
E. A. J. Burke
Affiliation:
Institute of Earth Sciences, Free University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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Summary

The third terrestrial occurrence of hibonite is reported from granulite-facies rocks in the Furua Granulite Complex in southern Tanzania. The mineral forms yellowish-brown lath-shaped crystals in a grossular-anorthite rock containing subordinate sphene (clino)zoisite, hercynite, apatite, ilmenite, and corundumilmenite intergrowths.

Electron-microprobe analyses indicate a generalized formula (Ca1−xREx)[(Al,Fe3+)12−2a+x(Ti,Si)(Ti,Si)a−x(Fe2+, Mg)a]O19, with RE = Ce + La + Nd, x = 0.2, and a = 0.8. Individual mineral analyses show a cation substitution of Ca + Ti + Fe3+ = RE + 2Al. Relatively high RE and Fe contents represent the main chemical differences with meteoritic hibonite. The hexagonal unit cell has a = 5.61 Å, c = 22.18, in good agreement with the other terrestrial hibonites.

Three compositional types of (clino)zoisite are distinguished: 1.8–3.1 wt% Fe2O3 (orthorhombic and monoclinic), 3.9–6.0 wt% Fe2O3 (monoclinic), and 5.8–7.9 wt% Fe2O3 with an average of 6.3 wt% RE2O3 (monoclinic).

Thermometric and barometric data for coexisting pyroxenes and garnet from adjacent rocks indicate granulite-facies equilibration conditions of 750 to 850 °C and 6 to 11 kb. During retrogression with increasing partial H2O pressures, hibonite reacted with plagioclase and garnet to form spinel, sphene, and RE-bearing clinozoisite. Corundum-ilmenite inter-growths probably resulted from the breakdown of an Fe-högbomite.

Type
Research Article
Information
Mineralogical Magazine , Volume 43 , Issue 332 , December 1980 , pp. 995 - 1003
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1980

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References

Ackermand, (D.) and Raase, (P.), 1973. Coexisting zoisite and dinozoisite in biotite schists from the Hohe Tauern, Austria. Contrib. Mineral. Petrol. 42, 333–41.CrossRefGoogle Scholar
Blander, (M.) and Fuchs, (L. H.), 1975. Calcium-aluminium-rich inclusions in the Allende meteorite. Evidence for a liquid origin. Geochim. Cosmochim. Acta, 39, 1605–9.CrossRefGoogle Scholar
Boettcher, (A. L.), 1970. The system CaO-Al2O3-SiO2--H2O at high pressures and temperatures. J. Petrol. 11, 337–79.CrossRefGoogle Scholar
Coolen, (J. J. M. M. M.), 1980. Chemical petrology of the Furua Granulite Complex, southern Tanzania. Ph.D. thesis, Free Univ. Amsterdam. GUA Papers of Geology,Ser. I, 13, 258 pp.Google Scholar
Curien, (H.), Guillemin, (C.), Orcel, (J.), and Sternberg, (M.), 1956. La hibonite, nouvelle espéce minérale. C.R. Acad. Sci. Paris, 242, 2845–7.Google Scholar
Hasegawa, (S.), 1960. Chemical composition of allanite. Sci. Report Tohoku Univ. Ser. 3 (Mineral. Petrol. Econ. Geol.), 6, 331.Google Scholar
Hepworth, (J. V.), 1972. Charnockitic granulites of some African cratons. 24th Internat. Geol. Congr. Montreal,Section I, 126–34.Google Scholar
Holdaway, (M. J.), 1966. Hydrothermal stability of clino-zoisite plus quartz. Am. J. Sci. 264, 643–67.CrossRefGoogle Scholar
Holdaway, (M. J.) 1972. Thermal stability of Al-Fe epidote as a function of fo2 and Fe content. Contrib. Mineral. Petrol. 37, 307–40.CrossRefGoogle Scholar
Huckenholz, (H. G.), Hölzl, (E.), and Lindhuber, (W.), 1975. Grossularite, its solidus and liquidus relations in the CaO-A12O3-SiO2-H2O system up to IO kbar. Neues Jahrb. Mineral. Abh. 124, 1–46.Google Scholar
Kato, (K.), 1967. Strukturverfeinerung von CaO “ 6A12O3 . Naturwiss. 54, 536.CrossRefGoogle Scholar
Keil, (K.) and Fuchs, (L. H.), 1971. Hibonite [Ca2(Al,Ti)24O38] from the Leoville and Allende chondritic meteorites. Earth Planet. Sci. Lett. 12, 184–90.CrossRefGoogle Scholar
Kieft, (C.) and Maaskant, (P.), 1969. Quantitative micro-probe-analyses of silicates: a comparison of different correction methods. Abstr. Confer. Roy. Microsc. Soc. Roy. Mineral. Soc. Manchester.Google Scholar
Kröner, (A.), 1977. The Precambrian geotectonic evolution of Africa: plate accretion versus plate destruction. Precambrian Res. 4, 163–213.CrossRefGoogle Scholar
Kröner, (A.) 1979. Pan-African mobile belts as evidence for a transitional tectonic regime from intraplate orogeny to plate margin orogeny. InAl Shanti (A. M. S.) (ed.), Evolution and mineralization of the Arabian-Nubian Shield. Oxford, Pergamon Press, pp. 21–37.CrossRefGoogle Scholar
Kuzmin, (A. M.), 1960. Högbomite from Gornaya Shoriya. Geol. Geof 4, 63–75.Google Scholar
Letuvninkas, (A. I.), 1971. Metasomatism in Proterozoic carbonate rocks from Gornaya Shoriya. Geol. Geof 1, 58–64.Google Scholar
Macdougall, (J. D.), 1979. Refractory-element-rich inclusions in CM meteorites. Earth Planet. Sci. Lett. 42, 1–6.CrossRefGoogle Scholar
Moore, (A. C.), 1971. Corundum-ilmenite and corundum-spinel associations in granulite facies rocks from central Australia. J. Geol. Soc. Australia, 17, 227–9.CrossRefGoogle Scholar
Myer, (G. H.), 1966. New data on zoisite and epidote. Am. J. Sci. 264, 364–85.CrossRefGoogle Scholar
Newton, (R. C.), 1965. The thermal stability of zoisite. J. Geol. 73, 431–41.CrossRefGoogle Scholar
Perkins, (D., III), Essene, (E. J.), Westrum, (E. F., Jr.), and Wall, (V. J.), 1977. Application of new thermodynamic data to grossular phase relations. Contrib. Mineral. Petrol, 64, 137–47.CrossRefGoogle Scholar
Priem, (H. N. A.), Boelrijk, (N. A. I. M.), Hebeda, (E. H.), Verdurmen, (E. A. Th.), Verschure, (R. H.), Oen, (I. S.), and Westra, (L.), 1979. Isotopic age determinations on granitic and gneissic rocks from the Ubendian-Usagaran System in southern Tanzania. Precambrian Res. 9, 227–39.CrossRefGoogle Scholar
Quennel, (A. M.), McKinlay, (A. C. M.), and Aitken, (W. G.), 1956. Summary of the geology of Tanganyika. Part I: Introduction and stratigraphy. Tanganyika Geol. Surv. Mem. 1, 264 pp.Google Scholar
Shimizu, (N.), Semet, (M. P.), and Allègre, (C. J.), 1978. Geochemical applications of quantitative ion-microprobe analysis. Geochim. Cosmochim. Acta, 42, I321–34.CrossRefGoogle Scholar
Smith, (J. V.), 1979. Mineralogy of the planets: a voyage in space and time. Mineral. Mag. 43, 1–89.CrossRefGoogle Scholar
Spooner, (C. M.), Hepworth, (J. V.), and Fairbairn, (H. W.), 1970. Whole-rock Rb-Sr isotopic investigation of some East African granulites. Geol. Mag. 107, 511–21.CrossRefGoogle Scholar
Springer, (G.), 1967. Die Berechnung von Korrekturen für die quantitative Elektronenstrahl-Mikroanalyse. Fortschr. Mineral. 45, 103–24.Google Scholar
Tröger, (W. E.), 1971. Optische Bestimmung der gesteins-bildenden Minerale. Stuttgart, E. Schweizerbart'sche Verlagsbuchhandlung, 188 pp.Google Scholar
Wendt, (I.), Besang, (C.), Harre, (W.), Kreuzer, (H.), Lenz, (H.), and Miiller, (P.), 1972. Age determinations of granitic intrusions and metamorphic events in the Early Precambrian of Tanzania. 24th Internat. Geol. Congr. Montreal,Section I, 295–314.Google Scholar
Yakovlevskaya, (T. A.), 1961. Hibonite from Gornaya Shoriya. Zap. Fses. Min. Obshch. 90, 458–61.Google Scholar