Abstract
Metamorphism to intermediate-pressure granulite grade had a minimal effect on the geochemistry of layered gneisses in central Australia. The overall composition of the terrain is granodioritic and major element compositions have equivalents in igneous and sedimentary supracrustal rocks. K, Rb, Sr and probably Th concentrations, and K/Rb ratios are normal; the initial isotopic composition of Sr shows the usual range of crustal rocks. However, U is strongly depleted and was lost by a pervasive process, probably dehydration, rather than by anatexis. Comparison with other areas in which major chemical depletions and unusually low initial Sr isotopic ratios are postulated leads to alternative interpretations of these areas which do not involve large scale chemical migration. An intermediate composition for the lower crust may result from a high density of basic intrusions rather than chemical processes.
Similar content being viewed by others
References
Arriens, P.A., Lambert, I.B.: On the age and strontium isotopic geochemistry of granulite-facies rocks from the Fraser Range, Western Australia, and the Musgrave Ranges, Central Australia. Spec. Publ. Geol. Soc. Aust. 2, 377–388 (1969)
Arth, J.G., Hanson, G.N.: Quartz diorites derived by partial melting of eclogite or amphibolite at mantle depths. Contrib. Mineral. Petrol. 37, 161–174 (1972)
Banno, S., Chappell, B.W.: X-ray fluorescent analysis of Rb, Sr, Y, Pb and Th in Japanese Palaeozoic slates. Geochem. J. 3, 127–134 (1969)
Clark, S.P. Jr., Peterman, Z.E., Heier, K.S.: Abundances of uranium, thorium and potassium. In: Handbook of Physical Constants. (S.P. Clark, Jr., ed.). Mem. Geol. Soc. Am. 97, 521–541 (1966)
Clifford, T.N.: Review of African Granulites and Related Rocks. Spec. Paper Geol. Soc. Am. 156 (1974)
Collerson, K.D.: Contrasted patterns of K/Rb distribution in Precambrian high grade metamorphic rocks from central Australia. J. Geol. Soc. Aust. 22, 145–158 (1975)
Compston, W., Lovering, J.F., Vernon, M.J.: The rubidium-strontium age of the Bishopville aubrite and its component enstatite and feldspar. Geochim. Cosmochim. Acta 29, 1085–1099 (1965)
Delong, S.E.: Distribution of Rb, Sr and Ni in igneous rocks, central and western Aleutian Islands, Alaska. Geochim. Cosmochim. Acta 38, 245–266 (1974)
Ewart, A., Stipp, J.J.: Petrogenesis of the volcanic rocks of the Central North Island, New Zealand, as indicated by a study of Sr87/Sr86 ratios, and Sr, Rb, K, U and Th abundances. Geochim. Cosmochim. Acta 32, 699–736 (1968)
Faure, G., Powell, J.L.: Strontium Isotope Geology. Berlin-Heidelberg-New York: Springer 1972
Gray, C.M.: Strontium isotopic studies on granulites. Unpubl. Ph.D. thesis, Aust. Nat. Univ. (1971)
Gray, C.M., Oversby, V.M.: The behaviour of lead isotopes during granulite facies metamorphism. Geochim. Cosmochim. Acta 36, 939–952 (1972)
Green, D.H., Ringwood, A.E.: An experimental investigation of the gabbro to eclogite transformation and its petrological applications. Geochim. Cosmochim. Acta 31, 767–833 (1967)
Green, T.H., Brunfelt, A.O., Heier, K.S.: Rare-earth element distribution and K/Rb ratios in granulites, mangerites and anorthosites, Lofoten-Vesteraalen, Norway. Geochim. Cosmochim. Acta 36, 241–257 (1972)
Heier, K.S.: Rubidium/strontium and strontium-87/strontium-86 ratios in deep crustal material. Nature 202, 477–478 (1964)
Heier, K.S., Compston, W., McDougall, I.: Thorium and uranium concentrations, and the isotopic composition of strontium in the differentiated Tasmanian dolerites. Geochim. Cosmochim. Acta 29, 643–659 (1965)
Heier, K.S., Thoresen, K.: Geochemistry of high grade metamorphic rocks, Lofoten-Vesteralen, North Norway. Geochim. Cosmochim. Acta 35, 89–99 (1971)
Lambert, I.B.: Investigations of high grade regional metamorphic and associated rocks. Unpubl. Ph.D. thesis, Aust. Nat. Univ. (1967)
Lambert, I.B., Heier, K.S.: The vertical distribution of uranium, thorium and potassium in the Continental Crust. Geochim. Cosmochim. Acta 31, 377–390 (1967)
Lambert, I.B., Heier, K.S.: Geochemical investigations of deepseated rocks in the Australian shield. Lithos 1, 30–53 (1968)
Lewis, J.D., Spooner, C.M.: K/Rb ratios in Precambrian granulite terrains. Geochim. Cosmochim. Acta 37, 1111–1118 (1973)
Major, R.B., Johnson, J.E., Leeson, B., Mirams, R.C.: S.A. Geological Atlas Series, Sheet SG52-12 Zone 4, Woodroffe. Geolog. Surv. of South Australia (1967)
Moorbath, S., Welke, H., Gale, N.H.: The significance of lead isotope studies in ancient, high-grade metamorphic basement complexes as exemplified by the Lewisian rocks of northwest Scotland. Earth Planet. Sci. Lett. 6, 245–256 (1969)
Nesbitt, R.W., Goode, A.D.T., Moore, A.C., Hopwood, T.P.: The Giles Complex, central Australia: A stratified sequence of mafic and ultramafic intrusions. Spec. Pub. Geol. Soc. S. Africa 1, 547–564 (1970)
Norrish, K., Hutton, J.T.: An accurate X-ray spectrographic method for the analysis of a wide range of geological samples. Geochim. Cosmochim. Acta 33, 431–453 (1969)
Shaw, D.M.: Geochemistry of pelitic rocks. Part III: Major elements and general geochemistry. Bull. Geol. Soc. Am. 67, 919–934 (1956)
Sheraton, J.W.: The origin of the Lewisian gneisses of northwest Scotland, with particular reference to the Drumbeg Area, Sutherland. Earth Planet. Sci. Lett. 8, 301–310 (1970)
Sighinolfi, G.P.: Investigations into the deeper levels of the continental crust: petrology and geochemistry of the granulite facies terrains of Bahia (Brazil). Atti. Soc. Tosc. Sci. Nat., Mem. Serie A. 77, 327–341 (1970)
Sighinolfi, G.P.: Investigations into deep crustal levels: Fractionating effects and geochemical trends related to high-grade metamorphism. Geochim. Cosmochim. Acta 35, 1005–1021 (1971)
Spooner, C.M., Fairbairn, H.W.: Strontium 87/Strontium 86 initial ratios in pyroxene granulite terranes. J. Geophys. Res. 75, 6706–6713 (1970)
Taylor, S.R.: Geochemistry of andesites. In: Origin and distribution of the elements (L.H. Ahrens, ed.), pp. 559–583. Oxford: Pergamon Press 1968
White, A.J.R.: Genesis of migmatites from the Palmer region of South Australia. Chem. Geol. 1, 165–200 (1966)
Whitney, P.R.: Variations in K/Rb ratio in migmatitic paragneisses of the Northwest Adirondacks. Geochim. Cosmochim. Acta 33, 1203–1211 (1969)
Wilson, A.F.: The charnockitic granites and associated granites of Central Australia. Trans. Roy. Soc. S.A. 83, 37–76 (1960)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gray, C.M. The geochemistry of central Australian granulites in relation to the chemical and isotopic effects of granulite facies metamorphism. Contr. Mineral. and Petrol. 65, 79–89 (1977). https://doi.org/10.1007/BF00373573
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00373573