Abstract
A test of the proposition that calc-alkaline magmas are direct partial melts of underthrust oceanic crust is presented. It involves numerical evaluations of whether or not the major and trace element and isotopic composition of a Fijian calc-alkaline rock suite is consistent with these rocks representing unfractionated partial melts of oceanic crust at high pressures. Experimental data for one of the samples constrain the calculations.
When compositions of liquidus minerals at 27 kb are combined with compositions of the volcanic rocks, close approximations can be made to the composition of oceanic crust only if the degree of partial melting is between ∼20% (dacite) and ∼45% (basaltic-andesite), and if accessory minerals are refractory phases. Concentrations of elements such as K, Rb, Sr, Pb, Th, and U, and 87Sr/86Sr ratios in the Fijian suite can be satisfactorily explained only if the parental material consisted of altered rather than fresh ocean floor basalt. Sediments are not likely to have been involved. Concentrations of Na, Ni, Co, Cr, Sc, V, the REE, Y, Zr, Hf, and Nb cannot be explained unless, or in some cases even if, several accessory phases are partially refractory. Therefore, partial melting of underthrust lithosphere does not seem likely to produce magmas with the composition of at least one quite typical calc-alkaline suite.
Similar content being viewed by others
References
Armstrong, R. L.: Isotopic and chemical constraints on models of magma genesis in volcanic arcs. Earth Planet. Sci. Lett. 12, 137–142 (1971)
Arth, J. G., Hanson, G. L.: Quartz diorites derived by partial melting of eclogite or amphibolite at mantle depths. Contr. Mineral. and Petrol. 37, 161–174 (1972)
Aumento, F.: Uranium contents of mid-oceanic basalts. Earth Planet. Sci. Lett. 11, 90–94 (1971)
Bakun-Czubarow, N.: The trace transition elements in the main minerals from eclogites. Abs. Int.'1. Geochm. Congr., Moscow. II, 444–445 (1971)
Banno, S., Green, D. H.: Experimental studies on eclogites: the roles of magnetite and acmite in eclogitic assemblages. Chem. Geol. 3, 21–32 (1968)
Boettoher, A. L.: Volcanism and orogenic belts-the origin of andesites. Tectonophysics 17, 223–240 (1973)
Brooks, C. K.: Concentrations of zirconium and hafnium in some igneous and metamorphic rocks and minerals. Geochim. Cosmochim. Acta 34, 411–416 (1970)
Brousse, R., Bizouard, H., Šalát, J.: Grenats des andésites et des rhyolites de Slovaquie, origine des grenats dans les séries andésitiques. Contr. Mineral. and Petrol. 35, 201–213 (1972)
Cambel, B., Jarkovský, J.: Geochemistry of pyrrhotite of various genetic types, 333pp. Bratislava: Komenský Univ. 1969
Cann, J. R.: Spilites from the Carlsberg Ridge, Indian Ocean. J. Petrol. 10, 1–19 (1969)
Cann, J. R.: Rb, Sr, Y, Zr and Nb in some ocean floor basaltic rocks. Earth Planet. Sci. Lett. 10, 7–11 (1970)
Cann, J. R.: Major element variations in ocean-floor basalts. Phil. Trans. Roy. Soc. London, Ser. A 268, 495–505 (1971)
Chase, C. G.: Tectonic history of the Fiji Plateau. Bull. Geol. Soc. Am. 82, 3087–3110 (1971)
Church, S. E.: Limits of sediment involvement in the genesis of orogenic volcanic rocks. Contr. Mineral, and Petrol. 39, 17–32 (1973)
Coleman, R. G., Lee, D. E., Beatty, L. B., Brannock, W. W.: Eclogites and eclogites: their differences and similarities. Bull. Geol. Soc. Am. 76, 483–508 (1965)
Dasch, E. J., Hedge, C. E., Dymond, J.: Effect of sea water interaction on strontium isotope composition of deep-sea basalts. Earth Planet. Sci. Lett. 19, 177–183 (1973)
DeLong, S. E.: Distribution of Rb, Sr, and Ni in igneous rocks, Central and Western Aleutian Islands, Alaska. Geochim. Cosmochim. Acta (in press)
Dickinson, W. R.: Widths of modern arc-trench gaps proportional to past duration of igenous activity in associated magmatic arcs. J. Geophys. Res. 78, 3376–3389 (1973)
Engel, A. E. J., Engel, C. G., Havens, R. G.: Chemical characteristics of oceanic basalts and the upper mantle. Bull. Geol. Soc. Am. 76, 719–734 (1965)
Fitton, J. G.: The generation of magmas in island arcs. Earth Planet Sci. Lett. 11, 63–67 (1971)
Fitton, J. G.: The genetic significance of almandine-pyrope phenocrysts in the calc-alkaline Borrowdale Volcanic Group, Northern England. Contr. Mineral, and Petrol. 36, 231–248 (1972)
Fleischer, M.: Minor elements in some sulfide minerals. Econ. Geol. 50th Ann. Vol., pp. 970–1024 (1955)
Frey, F. A., Haskin, M. A., Pbetz, J. A., Haskin, L. A.: Rare earth abundances in some basic rocks. J. Geophys. Res. 73, 6085–6098 (1968)
Gill, J. B.: Geochemistry of Viti Levu, Fiji, and its evolution as an island arc. Contr. Mineral. and Petrol. 27, 179–203 (1970)
Gill, J. B., Compston, W.: Strontium isotopes in island arc volcanic rocks. In: The Western Pacific-island arcs, marginal seas, geochemistry (ed. P. Coleman), p. 483–496. Perth: W. Austral. Univ. Press 1973
Gill, J. B., Gorton, M.: A proposed geological and geochemical history of Eastern Melanesia. In: The Western Pacific-island arcs, marginal seas, geochemistry (ed. P. Coleman). p. 543–566. Perth: W. Austral. Univ. Press 1973
Gill, J. B., McDougall, I.: Biostratigraphic and geologic significance of Miocene-Pliocene volcanism in Fiji. Nature 241, 176–180 (1973)
Green, D., Cullen, D. J.: The tectonic evolution of the Fiji region. In: The Western Pacificisland arcs, marginal seas, and geochemistry (ed. P. Coleman), p. 127–146. Perth: W. Austral. Univ. Press 1973
Green, D. H., Ringwood, A. E.: A comparison of recent experimental data on the gabbrogarnet granulite-eclogite transition. J. Geol. 80, 277–288 (1972)
Green, T. H.: High pressure experimental investigations on the origin of high-alumina basalt, andesite, and anorthosite. Unpub. Ph. D. thesis, A. N. U. (1967)
Green, T. H.: Crystallization of calo-alkaline andesite under controlled high-pressure hydrous conditions. Contr. Mineral. and Petrol. 34, 150–166 (1972)
Green, T. H., Ringwood, A. E.: Genesis of the calc-alkaline igneous rock suite. Contr. Mineral. and Petrol. 18, 105–162 (1968)
Griffin, W. L., Raheim, A.: Convergent metamorphism of eclogites and dolerites, Kristiansund area, Norway. Lithos 6, 21–40 (1973)
Hammaguchi, H., Kuroda, R.: Tin. In: Handbook of geochemistry (ed. K. H. Wedepohl), p. 50-E-1-5. Berlin-Heidelberg-New York: Springer 1969
Hanson, G. N., Goldich, S. S.: Early Precambrian rocks in the Saganaga Lake-Northern Light Area, Minnesota-Ontario Part II; petrogenesis. Geol. Soc. Am. Mem. 135, 179–192 (1972)
Hart, R.: Chemical exchange between sea water and deep ocean basalts. Earth Planet. Sci. Lett. 9, 269–279 (1970)
Hart, R.: Geochemical and geophysical implications of the reaction between sea water and the oceanic crust. Nature 243, 76–78 (1973)
Hart, S. R.: K, Rb, Cs contents and K/Rb, K/Cs ratios of fresh and altered submarine basalts. Earth Planet Sci. Lett. 6, 295–303 (1969)
Hart, S. R.: K, Rb, Cs, Sr, and Ba contents and Sr isotope ratios of ocean floor basalts. Phil. Trans. Roy. Soc. London, Ser. A 268, 573–587 (1971)
Hedge, C. E., Lewis, J. F.: Isotopic composition of strontium in three basalt-andesite centers along the Lesser Antilles Arc. Contr. Mineral, and Petrol. 32, 39–47 (1971).
Hekinian, R.: Chemical and mineralogical differences between abyssal hill basalts and ridge tholeiites in the eastern Pacific Ocean. Marine Geol. 11, 77–91 (1971)
Hill, R. E. T., Boettcher, A. L.: Water in the Earth's mantle: melting curves of basalt-water and basalt-water-carbon dioxide. Science 167, 980–981 (1970)
Holloway, J. R., Burnham, C. W.: Melting relations of basalt with equilibrium water pressures less than total pressure. J. Petrol. 13, 1–29 (1972)
Huang, W. L., Wyllie, P. J.: Muscovite dehydration and melting in deep crust and subducted oceanic sediments. Earth Planet. Sci. Lett. 18, 133–136 (1973)
Jakeš, P., Gill, J.: Rare earth elements and the island arc tholeiitic series. Earth Planet. Sci. Lett. 9, 17–28 (1970)
Jakeš, P., White, A. J. R.: K/Rb ratios of rocks from island arcs. Geochim. Cosmochim Acta 34, 849–856 (1970)
Lambert, I. B., Wyllie, P. J.: Low-velocity zone of the Earth's mantle: incipient melting caused by water. Science 169, 764–766 (1970)
MacLean, W. H.: Liquidus phase relationships in the FeS-FeO-Fe3O4-SiO2 system, and their application in geology. Econ. Geol. 64, 865–884 (1969)
Masuda, A.: Lanthanide concentration ratios between pyroxene and garnet. Earth Planet Sci. Lett. 3, 25–28 (1967)
Masuda, A., Kushiro, L: Experimental determination of partition coefficients of ten rare earth elements and barium between clinopyroxene and liquid in the synthetic silicate system at 20 kilobar pressure. Contr. Mineral, and Petrol. 26, 42–49 (1970)
Melson, W. G., Thompson, G.: Petrology of a transform fault zone and adjacent ridge segments. Phil. Trans. Roy. Soc. London, Ser. A 268, 423–441 (1971)
Melson, W. G., Thompson, G., Andel, T. van: Volcanism and metamorphism in the Mid-Atlantic Ridge, 22° N Latitude. J. Geophys. Res. 73, 5925–5943 (1968)
Meyer, H. O. A., Brookins, D. G.: Eclogite xenoliths from Stoekdale Kimberlite, Kansas. Contr. Mineral, and Petrol. 34, 60–72 (1971)
Nagasawa, H.: Rare earth concentration in zircon and apatite and their host dacites and granites. Earth Planet. Sci. Lett. 5, 47–51 (1970)
Naldrett, A. J.: A portion of the system Fe-S-O between 900 and 1080° C and its application to sulfide ore magmas. J. Petrol. 10, 171–201 (1969).
Nicholls, I. A., Ringwood, A. E.: Effect of water on olivine stability in tholeiites and the production of silica-saturated magmas in the island arc environment. J. Geol. 81, 285–300 (1973)
Oversby, V. M., Ewart, A.: Lead isotopic composition of Tonga-Kermadec volcanics and their petrogenetic significance. Contr. Mineral, and Petrol. 37, 181–210 (1972)
Parker, R.L., Fleischer, M.: Geochemistry of niobium and tantalum. U.S. Geol. Surv. Prof. Pr. 612 (1968)
Pearce, J. A., Cann, J. R.: Ophiolite origin investigated by discriminant analysis using Ti, Zr, and Y. Earth Planet. Sci. Lett. 12, 339–349 (1971)
Philpotts, J. A., Martin, W., Schnetzler, C. C.: Geochemical aspects of some Japanese lavas. Earth Planet. Sci. Lett. 12, 89–96 (1971)
Philpotts, J. A., Schnetzler, C. C., Hart, S. R.: Submarine basalts: some K, Rb, Sr, Ba, rareearth, H2O, and CO2 data bearing on their alteration, modification by plagioclase, and possible source materials. Earth Planet. Sci. Pett. 7, 293–299 (1969)
Philpotts, J. A., Schnetzler, C. C., Thomas, H. H.: Petrogenetic implications of some new geochemical data on eclogitic and ultrabasic inclusions. Geochim. Cosmochim. Acta 36, 1131–1166 (1972)
Rodda, P.: Outline of the geology of Viti Levu. New Zealand J. Geol. Geophys. 10, 1260–1273 (1967)
Schilling, J. G.: Sea-floor evolution: rare-earth evidence. Phil. Trans. Roy. Soc. London, Ser. A 268, 663–706 (1971)
Shaw, D. M.: Trace element fractionation during anatexis. Geochim. Cosmochim. Acta 34, 237–242 (1970)
Shaw, D. M.: Development of the early continental crust. Part 1. Use of trace element distribution coefficient models for the Protoarchean crust. Can. J. Earth Sci. 9, 1577–1595 (1973)
Stern, C. R., Wyllie, P. J.: Water-saturated and under-saturated melting relations of a granite to 35 kilobars. Earth Planet. Sci. Lett. 18, 163–167 (1973)
Switzer, G., Melson, W. G.: Partially melted kyanite eclogite from the Roberts Victor Mine, South Africa. Smithsonian Contr. Earth Sciences No. 1 (1969)
Tatsumoto, M.: Lead isotopes in volcanic rocks and possible ocean floor thrusting beneath island arcs. Earth Planet. Sci. Lett. 6, 369–376 (1969)
Taylor, S.R.: Trace element chemistry of andesites and associated calc-alkaline rocks. In: Proc. Andesite Conf. (ed. A. R. McBirney), Dept. Geol. Min. Res. Oregon Bull. 65, 43–64 (1969)
Taylor, S. R., Capp, A. C., Graham, A. L., Blake, D. H.: Trace element abundances in andesites II. Saipan, Bougainville and Fiji. Contr. Mineral, and Petrol. 23, 1–26 (1969a)
Taylor, S. R., Kaye, M., White, A. J. R., Duncan, A. R., Ewart, A.: Genetic significance of Co, Cr, Ni, Sc, and V in andesites. Geochim. Cosmochim. Acta 33, 275–286 (1969b)
Taylor, S. R., White, A. J. R.: Trace element abundances in andesites. Bull. Volcanol. 29, 177–194 (1966)
Turekian, K. K., Wedepohl, K. H.: Distribution of the elements in some major units of the Earth's crust. Bull. Geol. Soc. Am. 72, 175–192 (1961)
Vlasov, K. A. (ed.): Geochemistry and mineralogy of rare elements and genetic types of their deposits, 3 volumes. Jerusalem: Israel Program for Scientific Translations 1966
Wedepohl, K. H.: Composition and abundance of common sedimentary rocks. In: Handbook of geochemistry (ed. K. H. Wedepohl), vol. I, p. 250–271. Berlin-Heidelberg-New York: Springer 1969
Wright, T. L., Doherty, P. C.: A linear programming and least squares computer method for solving petrologic mixing problems. Bull. Geol. Soc. Am. 81, 1995–2008 (1970)
Wyllie, P. J.: Role of water in magma generation and initiation of diapiric uprise in the mantle. J. Geophys. Res. 76, 1328–1338 (1971 b)
Yajima, T., Higuchi, H., Nagasawa, H.: Variation of rare earth concentrations in pigeonitic and hypersthenic rock series from Izu-Hakone Region, Japan. Contr. Mineral. and Petrol. 35, 235–244 (1972)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gill, J.B. Role of underthrust oceanic crust in the genesis of a Fijian calc-alkaline suite. Contr. Mineral. and Petrol. 43, 29–45 (1974). https://doi.org/10.1007/BF00384650
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00384650