Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-23T18:30:26.633Z Has data issue: false hasContentIssue false
  • English
  • Français

Geothermometry and geobarometry of high-grade rocks: a case study on garnet-pyroxene granulites in southern Sri Lanka

Published online by Cambridge University Press:  05 July 2018

S. Faulhaber  and
M. Raith
S. Faulhaber
Affiliation:
Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, 5300 Bonn, FRG
M. Raith
Affiliation:
Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, 5300 Bonn, FRG
Get access Rights & Permissions [Opens in a new window]

Abstract

In the central granulite belt of Sri Lanka, garnet-pyroxene granulites of granitic and gabbro-noritic composition are the most abundant rock types. The micro-structures and mineral chemistry data prove complete attainment of textural and large-scale chemical equilibrium during and following a phase of extreme penetrative deformation at conditions of the granulite facies (800–850 °C, 5 to 9 kbar). On a local scale, especially along the intergranular system, continued cation exchange decoupling from the early ceasing net-transfer reactions destroyed the near-peak metamorphic equilibrium. The extreme compositional variation of the coexisting ferro-magnesian phases (Fe/(Fe + Mg): gar 0.98−0.65, opx 0.92−0.40, cpx 0.88−0.28) and the near-isothermal conditions of equilibration throughout the studied area enabled examination of the effects of non-ideal mixing in garnet and pyroxenes on the equilibrium constants of reactions used in geothermobarometry, and tests on the quality of commonly applied thermometers/barometers and the validity of activity models adopted in the calibrations. The Sri Lankan data set reveals more or less pronounced compositional dependences for all of the tested gar-opx/gar-cpx Fe-Mg exchange thermometers and the opx + plg ⇌ gar + qtz barometers. Evidently the recommended solution models do not adequately describe the mixing properties of the involved ferro-magnesium mineral phases (garnet, orthopyroxene and clinopyroxene).

Keywords

geothermometrygeobarometrygarnetpyroxenegranuliteSri Lanka
Type
Research Article
Information
Mineralogical Magazine , Volume 55 , Issue 378 , March 1991 , pp. 33 - 56
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1991

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

Aranovich, L. Ya. and Podlesski, K. K. (1989) Geothermobarometry of high-grade metapelites: simultaneously operating reactions. In Evolution of Metamorphic Belts (Daly, J. S., Cliff, R. A., and Yardley, B. W. D., eds.) Geol. Soc. Spec. Publ., 43, 45–61.Google Scholar
Berger, A. R. and Jayasinghe, N. R. (1976) Precambrian structure and chronology in the Highland Series of Sri Lanka. Precambrian Res., 3, 559–76.CrossRefGoogle Scholar
Berman, R. G. (1988) Internally-consistent thermodynamic data for minerals in the system Na2O–K2O–CaO–MgO–FeO–Fe2O3–Al2O3–SiO2–TiO2–H2O–CO2 . J. Petrol., 29, 445–552.CrossRefGoogle Scholar
Berman, R. G. (1990) Mixing properties of Ca-Mg-Fe-Mn garnets. Am. Mineral., 75, 328–44.Google Scholar
Bhattacharya, A., Krishnakumar, K., Raith, M., and Sen, S. K. (1990) An improved set of a-X parameters in Fe-Mg-Ca garnets and refinement of the orthopyroxene-garnet thermometer and the garnetorthopyroxene- plagioclase∼:luartz barometer. Submitted to J. Petrol.CrossRefGoogle Scholar
Blencoe, J. G., Merkel, G. A., and Seil, M. K. (1982) Thermodynamics of crystal-fluid equilibria, with applications to the system NaAlSi3O8–CaAl2Si2O8–SiO2–NaCl–CaCl–H2O. In Advances in Physical Geochemistry, 2, (Saxena, S. K., ed.), 191–223. Springer Verlag, New York.CrossRefGoogle Scholar
Bohlen, S. R., Wall, V. J., and Boettcher, A. L. (1983) Experimental investigation and application of garnet granulite equilibria. Contrib. Mineral. Petrol., 83, 52–61.CrossRefGoogle Scholar
Chatillon-Colinet, C., Newton, R. C., Perkins, D. III, and Kleppa, O. J. (1983) Thermochemistry of (Fe2+–Mg)SiO3 orthopyroxene. Geochim. Cosmochim. Acta, 47, 1597–603.CrossRefGoogle Scholar
Chatterjee, N. (1987) Evaluation of thermochemical data on Fe-Mg olivine, orthopyroxene, spinel and Ca-Fe-Mg-AI garnet. Ibid., 51, 2515–25.Google Scholar
Cooray, P. G. (1978) Geology of Sri Lanka. In Proceedings of the 3rd regional conference on geology and mineral resources of SE-Asia. Bangkok, Thailand, 701–10.Google Scholar
Dahl, P. S. (1980) The thermal-compositional dependence of Fe2+-Mg distributions between coexisting garnet and pyroxene: applications to geothermomerry. Am. Mineral., 65, 854–66.Google 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
Faulhaber, S. (1991) Die Granat-Pyroxen Granulite Siid-Sri Lankas: Petrologie und Geothermobarometrie. Ph.D. Thesis, University of Bonn, FRG.Google Scholar
Fiorentini, E., Hoernes, S., Hoffbauer, R., and Vitanage, P. W. (1990) Nature and scale of fluid-rock exchange in granulite grade rocks of Sri Lanka: a stable isotope study. In Granulites and Crustal Evolution (Vielzeuf, D. and Vidal, Ph., eds.) NATO ASI Series, Series C, Vol. 311, 311–38.CrossRefGoogle Scholar
Frost, B. R. and Chacko, T. (1989) The granulite uncertainty principle: limitations on thermobaromerry in granulites. J. Geol., 97, 435–50.CrossRefGoogle Scholar
Ganguly, J. (1979) Garnet and clinopyroxene solid solutions, and geothermometry based on Fe-Mg distribution coefficient. Geochim. Cosmochim. Acta, 43, 1021–9.CrossRefGoogle Scholar
Ganguly, J. and Saxena, S. K. (1984) Mixing properties of aluminosilicate garnets: constraints from natural and experimental data, and applications to geothermobarometry. Am. Mineral., 69, 88–97.Google Scholar
Geiger, C. A., Newton, R. C., and Kleppa, O. J. (1987) Enthalpy of mixing of synthetic almandine-grossular and almandine-pyrop garnets from high temperature solution calorimetry. Geoehim. Cosmochim. Acta, 51, 1755–63.CrossRefGoogle Scholar
Harley, S. L. (1984) An experimental study of the partitioning of Fe and Mg between garnet and orthopyroxene. Contrib. Mineral. Petrol., 86, 359–73.CrossRefGoogle Scholar
Hodges, K. V. and Spear, F. S. (1982) Geothermometry, geobarometry and the Al2SiO5 triple point at Mt. Moosilauke, New Hampshire. Am. Mineral., 67, 1118–34.Google Scholar
Holland, T. J. B. and Powell, R. (1990) An enlarged and updated internally consistent thermodynamic dataset with uncertainties and correlations: the system K2O–Na2O–CaO–MgO–MnO–FeO–Fe2O3–Al2O3–TiO2–SiO2–C–H2O–O2. J. Metamorph. Geol., 8, 89–124.CrossRefGoogle Scholar
Hölzl, S. and Köhler, H. (1989) U-Pb-Geochronologie an Unterkrustengesteinen Sri Lankas. Europ. J. Mineral., l, 75.Google Scholar
Katz, M. B. (1971) The Precambrian metamorphic rocks of Ceylon. Geol. Rundschau, 60, 1523–49.CrossRefGoogle Scholar
Krogh, E. J. (1988) The garnet-clinopyroxene Fe-Mg geothermometera reinterpretation of existing experimental data. Contrib. Mineral. Petrol., 99, 448.CrossRefGoogle Scholar
Milisenda, C. C., Liew, T. C., Hofmann, A. W., and Kröner, A. (1988) Isotopic mapping of age provinces in Precambrian high-grade terrains: Sri Lanka. J. Geol., 96, 608–15.CrossRefGoogle Scholar
Newton, R. C. and Perkins, D. III (1982) Thermodynamic calibration of geobarometers based on the assemblages garnet-plagioclase-orthopyroxene (clinopyroxene)-quartz. Am. Mineral., 67, 230–22.Google Scholar
Newton, R. C., Charlu, T. V., and Kleppa, O. J. (1977) Thermochemistry of high pressure garnets and clinopyroxenes in the system CaO–MgO–Al2O3–SiO2 . Geochim. Cosmochim. Acta, 41, 369–77.CrossRefGoogle Scholar
Pattison, D. R. M. and Newton, R. C. (1989) Reversed experimental calibration of the garnet-clinopyroxene Fe-Mg exchange thermometer. Contrib. Mineral. Petrol., 101, 87–103.CrossRefGoogle Scholar
Perchuk, L. L., Aranovich, L. Ya., Podlesskii, K. K., Lavrant'eva, I. V., Gerasimov, V. Yu., Fed'kin, V. V., Kitsul, V. I., Karsakov, L. P., and Berdnikov, N. V. (1985) Precambrian granulites of the Aldan shield, eastern Siberia U.S.S.R. J. Metamorph. Geol., 3, 265–310.CrossRefGoogle Scholar
Perkins, D. III and Chipera, S. J. (1985) Garnet-ort hopyroxene-plagioclase-quartz baromerry: refinement and application to the English River subprovince and the Minnesota River valley. Contrib. Mineral. Petrol., 89, 69–80.CrossRefGoogle Scholar
Perkins, D. III and Newton, R. C. (1981) Charnockite geobarometers based on coexisting garnet-pyroxeneplagioclase-quartz. Nature, 292, 144–6.CrossRefGoogle Scholar
Powell, R. and Holland, T. J. B. (1985) An internally consistent thermodynamic dataset with uncertainties and correlations: 1. Methods and a worked example. J. Metamorph. Geol., 3, 327–42.CrossRefGoogle Scholar
Råheim, A. and Green, D. H. (1974) Experimental determination of the temperature and pressure dependence of the Fe-Mg partition coefficient for coexisting garnet and clinopyroxene. Contrib. Mineral. Petrol., 48, 179–203.CrossRefGoogle Scholar
Sandiford, M., Powell, R., Martin, S. F., and Perera, L. R. K. (1988) Thermal and baric evolution of garnet granulites from Sri Lanka. J. Metamorph. Geol., 6, 351–64.CrossRefGoogle Scholar
Saxena, S. K. (1979) Garnet-clinopyroxene geothermometer. Contrib. Mineral. Petrol., 70, 229–35.CrossRefGoogle Scholar
Schumacher, R., Schenk, V., Raase, P., and Vitanage, P. W. (1990) Granulite facies metamorphism of metabasic and intermediate rocks in the Highland Series of Sri Lanka. In High-grade metamorphism and crustal anatexis (Ashworth, J. R. and Brown, M., eds.) Allan & Unwin, London.Google Scholar
Selverstone, J. and Chamberlain, C. P. (1990) Apparent isobaric cooling paths from granulites: two counterexamples from British Columbia and New Hampshire. Geology, 18, 307–10.2.3.CO;2>CrossRefGoogle Scholar
Sen, S. K. and Bhattacharya, A. (1984) An orthopyroxene-garnet thermometer and its application to the Madras charnockites. Contrib. Mineral. Petrol., 88, 64–71.CrossRefGoogle Scholar
Sharma, K. C., Agrawal, R. D., and Kapoor, M. L. (1987) Determination of thermodynamic properties of (Fe-Mg)-pyroxenes at 1000 K by the emf method. Earth Planet. Sci. Lett., 85, 302–10.CrossRefGoogle Scholar
Vitanage, P. W. (1985) The geology, structure and tectonics of Sri Lanka and South India. In Recent Advances in the Geology of Sri Lanka (Dissanayake, C. B. and Cooray, P. G., eds.) Centre international pour la formation et les 6changes géologiques, CIFEG. Publication occasionalle No. 6, 5–15.Google Scholar