Abstract
The Maladeta plutonic complex formed during the latest stages of the Variscan orogeny. It was emplaced into the Paleozoic sedimentary sequence of the Pyrenees. The eastern part, investigated in the present study, consists of an early intrusion of cumulate gabbronorites followed in order of emplacement by the main biotite-hornblende granodiorite, which was itself intruded by two small stocks of two-mica cordierite granite. An 87Rb-87Sr isochron dates the granodiorite at 277±7 m.y. with an initial (87Sr/86Sr)o ratio of 0.7117±3. Gabbroic rocks have lower strontium initial ratios, down to 0.7092, while those of granite range from that of the granodiorite up to about 0.715. The three rock types have distinctive δ18O values: 8.7 to 9.6 for the gabbronorites, 9.4 to 10.4 for the granodiorites and 10.3 to 11.8 for the granites. Lead isotopic compositions of rocks and feldspars are all radiogenic. Feldspars give consistent Pb model ages around 280 m.y., with μ and κ values of about 9.7 and 4.05, respectively. No pristine, mantle-derived magma was found among the investigated samples and the rocks cannot be related to one another by any simple mechanism of fractional crystallization. Some type of mixing process involving two end members seems to be required: a high-18O, high-87Sr material that is clearly of crustal origin, and a lower-18O, lower-87Sr end member derived from the mantle. Examination of various mixing models does not support magma mixing nor assimilation of crustal rocks by a mafic magma. The most acceptable model involves melting at different levels of a vertically-zoned source in the continental crust; this source was formed by mixing between mantle-derived magmas and crustal metasediments. This material was apparently thickened, tectonically downwarped and partially melted. None of the Maladeta magma-types appear to have been derived at a consuming plate boundary.
Similar content being viewed by others
References
Albarède, F.: Some trace element relationships among solid and liquid phases in the course of the fractional crystallisation of magmas. Geochim. Cosmochim. Acta 40, 667–673 (1976a)
Albarède, F.: Thermal models of post-tectonic decompression as exemplified by the Haut-Allier granulites (Massif Central, France) Bull. Soc. Geol. Fr. 18, 1023–1032 (1976b)
Armstrong, R.L., Taubeneck, W.H., Haes, P.O.: Rb-Sr and K-Ar geochronology of Mesozoic granitic rocks and their Sr isotopic composition, Oregon, Washington and Idaho. Geol. Soc. Am. Bull. 88, 397–411 (1977)
Arthaud, F., Matte, P.: The Paleozoic strike-slip faulting in southern Europe and northern America: result of a right-lateral shear zone between the Appalachians and the Urals. Geol. Soc. Am. Bull. 88, 1305–1320 (1977)
Autran, A., Guitard, G.: Sur le granite de Mont-Louis (Pyrénées orientales). Bull. Soc. Geol. Fr. 7, 245–270 (1957)
Autran, A., Fonteilles, M., Guitard, G.: Relations entre les intrusions de granitoïdes, l'anatexie et le métamorphisme régional considérés principalement du point de vue du rôle de l'eau: cas de la chaîne hercynienne des Pyrénées orientales. Bull. Soc. Geol. Fr. 12, 673–731 (1970)
Bard, J.P., Capdevila, R., Matte, P.: La structure de la chaîne hercynienne de la Meseta Ibérique: comparaison avec les segments viosins. IFP-CNEXO Symp. Golfe de Gascogne, Rueil-Malmaison (IFP, ed.) I-4, 1–68 (1971)
Bateman, P.C., Clark, L.D., Huber, N.K., Moore, J.G., Rinehart, C.D.: The Sierra Nevada batholith. A synthesis of recent work across the central part. U.S. Geol. Survey Prof. Paper 414D (1963)
Birck, J.L., Allègre, C.J.: Chronology and chemical history of the parent body of basaltic achondrites studied by the 87Rb-87Sr method. Earth Planet. Sci. Lett. 39, 37–51 (1978)
Bottinga, Y., Javoy, M.: Oxygen isotope partitioning among the minerals in igneous and metamorphic rocks. Rev. Geophys. Space Phys. 13, 401–418 (1975)
Bowen, N.L.: The evolution of the igneous rocks. Princeton: Princeton Univ. Press 1928
Capdevila, R., Corretge, G., Floor, P.: Les granitoïdes varisques de la Meseta Ibérique. Bull. Soc. Geol. Fr. 15, 208–228 (1973)
Chappell, B.W., White, A.J.R.: Two contrasting granite types. Pac. Geol. 8, 173–174 (1974)
Charlet, J.M.: Etude préliminaire du massif granitique de la Maladeta (Pyrénées Centrales Espagnoles). Ann. Soc. Geol. Nord 88, 65–75 (1968)
Charlet, J.M.: Les grands traits géologiques du Massif de la Maladeta, Pyrénées Centrales Espagnoles. Proc. 7th Int. Congr. Pyrenean Studies, Seo de Urgel 1974
Charlet, J.M., Dupuis, C.: Observations nouvelles dans le massif de la Maladeta. Ibid
Cobbing, E.J., Pitcher, W.S.: The Coastal Batholith of Central Peru. J. Geol. Soc, London 128, 421–460 (1972)
Cogné, J.: Métamorphismes et granitisations en liaison avec l'évolution orogénique en Bretagne méridionale. Bull. Soc. Geol. Fr. 7, 213–226 (1960)
Compston, W., Lovering, J.F.: The strontium isotopic chemistry of granulitic and eclogitic inclusions from the basic pipes at Delegate, eastern Australia. Geochim. Cosmochim. Acta 33, 691–699 (1969)
Dasch, E.J.: Strontium isotopes in weathering profiles, deap-sea sediments and sedimentary rocks. Geochim. Cosmochim. Acta 33, 1521–1552 (1969)
Debon, F.: Les massifs granitoïdes à structure concentrique de Cauterets-Panticosa (Pyrénées occidentales) et leurs enclaves. Sci. Terre, Nancy, Mem. 33 (1975)
Didier, J.: Granites and their enclaves. Amsterdam: Elsevier 1973
Didier, J., Lameyre, J.: Les roches granitiques du Massif Central. In: Géologie du Massif Central Français, J. Jung Symp., Ed. Sci. Clermont-Ferrand 1971
Doe, B.R., Delevaux, M.: Variation in lead isotopic compositions in mesozoic granitic rocks of California: a preliminary investigation. Geol. Soc. Am. Bull. 84, 3513–3526 (1973)
Doe, B.R., Zartman, R.E.: Plumbotectonics. In: Geochemistry of ore deposits (H. Barnes, ed.), 2nd edition. New York: Wiley 1979
Eggler, D.H.: Water-saturated and undersaturated melting relationships in a Paricutin andesite and an estimate of water content in the natural magma. Contrib. Mineral. Petrol. 34, 261–271 (1972)
Faure, G.: Principles of Isotope Geology. New York: Wiley 1977
Fourcade, S., Javoy, M.: Rapports 18O/16O dans les roches du vieux socle catazonal d'In Ouzzal (Sahara Algerien). Contrib. Mineral. Petrol. 42, 235–244 (1973)
Gastil, R.G.: Plutonic zones in the Peninsular Ranges of southern California and northern Baja California. Geology 3, 361–363 (1975)
Gray, C.M., Oversby, V.M.: The behaviour of lead isotopes during granulite facies metamorphism. Geochim. Cosmochim. Acta 36, 939–952 (1972)
Gulson, B.L., Krogh, T.E.: Old lead component in the young Bergell Massif, South East Swiss Alps. Contrib. Mineral. Petrol. 40, 239–252 (1973)
Hamet, H., Allègre, C.J.: Hercynian orogeny in the Montagne Noire (France): application of 87Rb-87Sr systematics. Geol. Soc. Am. Bull. 87, 1429–1442 (1976)
Hamilton, W., Myers, W.B.: The nature of batholiths. U.S. Geol. Survey Prof. Paper 554 C (1967)
Hawkesworth, C.J., Vollmer, R.: Crustal contamination versus enriched mantle: 143Nd/144Nd and 87Sr/86Sr evidence from the Italian volcanics. Contrib. Mineral. Petrol. 69, 151–165 (1979)
Heier, K.S.: Radioactive elements in the continental crust. Nature 208, 479–480 (1965)
Heyl, A.V., Landis, G.P., Zartman, R.E.: Isotopic evidence for the origin of Mississippi Valley-type mineral deposits: a review. Econ. Geol. 69, 992–1006 (1974)
Hodges, F.N., Papike, J.J.: DSDP site 334: Magmatic cumulates from oceanic layer 3. J. Geophys. Res. 81, 4135–4151 (1976)
Honma, H., Sakai, H.: Zonal distribution of oxygen isotope ratios in the Hiroshima granite complex, Southwest Japan. Lithos 9, 173–178 (1976)
James, D.E.: Andean crustal and upper mantle structure. J. Geophys. Res. 76, 3246–3271 (1971)
James, D.E., Brooks, C., Cuyubamba, A.: Andean Cenozoic volcanism magma genesis in the light of strontium composition and trace element geochemistry. Geol. Soc. Am. Bull. 87, 592–600 (1976)
Javoy, M.: Utilisation des isotopes de l'oxygène en magmatologie. Unpubl. Thesis Paris 1970
Kistler, R.W., Peterman, Z.E.: Variation in Sr, Rb, K, Na and initial Sr87/Sr86 in Mesozoic granitic rocks and intruded wall rocks in California. Geol. Soc. Am. Bull. 84, 3489–3512 (1973)
Krebs, W., Wachendorf, H.: Proterozoic-Paleozoic geosynclinal and orogenic evolution of Central Europe. Geol. Soc. Am. Bull. 84, 2611–2630 (1973)
Larsen, E.S.: The batholith of Southern California. Geol. Soc. Am., Mem. 29 (1948)
Leterrier, J.: Etude pétrographique et géochimique du massif granitique de Querigut. Sci. Terre Nancy Mem. 23 (1972)
Magaritz, M., Taylor, H.P., Jr: Oxygen, hydrogen and carbon isotope studies of the Franciscan formation, Coast Ranges, California. Geochim. Cosmochim. Acta 40, 215–234 (1976)
Manhes, G., Minster, J.F., Allègre, C.J.: Comparative uraniumthorium-lead and rubidium-strontium study of the Saint Severin amphoterite: consequences for early solar system chronology. Earth Planet. Sci. Lett. 39, 14–24 (1978)
Marre, J.: Le complexe éruptif de Querigut. Unpubl. Thesis, Toulouse 1973
Masi, U., O'Neil, J.R., Kistler, R.: Stable isotope systematics in Mesozoic granites near the San Andreas and Garlock fault systems, California. Geol. Soc. Am. Abstracts with Programs, Denver Mtg. 998 (1976)
Masuda, A., Nakamura, N., Tanaka, T.: Rare earth elements in metagabbros from the Mid-Atlantic Ridge and their possible implications for the genesis of alkali olivine basalts as well as the Lizard peridotite. Contrib. Mineral. Petrol. 32, 295–306 (1971)
Mehnert, K.R.: Migmatites and the origin of granitic rocks. Amsterdam: Elsevier 1968
Moorbath, S., Welke, H.: Lead isotope studies on igneus rocks from the Isle of Skye, Northwest Scotland. Earth Planet. Sci. Lett. 5, 217–230 (1968)
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)
Muehlenbachs, K., Clayton, R.N.: Oxygen isotope studies of fresh and weathered submarine basalts. Can. J. Earth Sci. 9, 172–184 (1972)
Nicolas, A., Bouchez, J.L., Blaise, J., Poirier, J.P.: Geological aspects of deformation in continental shear zones. Tectonophysics 42, 55–73 (1977)
O'Neil, J.R., Chappell, B.W.: Oxygen and hydrogen isotope relations in the Berridale batholith. J. Geol. Soc., London 133, 559–571 (1977)
O'Neil, J.R., Shaw, S.E., Flood, R.H.: Oxygen and hydrogen isotope compositions as indicators of granite genesis in the New England batholith, Australia. Contrib. Mineral. Petrol. 62, 313–328 (1977)
Philpotts, J.A., Schnetzler, C.C.: Europium anomaly and the genesis of basalts. Chem. Geol. 3, 5–13 (1968)
Pitcher, W.S.: The anatomy of a batholith. J. Geol. Soc., London 135, 157–182 (1978)
Ramberg, H.: Fluid dynamics of layered systems in the field of gravity, a theoretical basis for certain global structures and isostatic adjustment. Phys. Earth Planet. Inter. 1, 63–87 (1968)
Richardson, K.A., Adams, J.A.S.: Effect of weathering on radioactive elements in the Conway granite of New Hampshire. Geol. Soc. Am., Spec. Pap. 76, 137 (1964)
Rosholt, J.N., Zartman, R.E., Nkomo, I.T.: Lead isotope systematics and uranium depletion in the Granite Mountains, Wyoming. Geol. Soc. Am. Bull. 84, 989–1002 (1973).
Savin, S.M., Epstein, S.: The oxygen and hydrogen isotope geochemistry of ocean sediments and shales. Geochim. Cosmochim. Acta 34, 43–63 (1970)
Shieh, Y.N., Taylor, H.P. Jr: Oxygen and hydrogen isotope studies of contact metamorphism in the Santa Rosa Range, Nevada, and other areas. Contrib. Mineral. Petrol. 20, 306–356 (1969)
Shieh, Y.N., Schwarcz, H.P.: An estimate of the oxygen isotope composition of a large segment of the Canadian shield in northwestern Ontario. Can. J. Earth Sci. 14, 927–931 (1977)
Sinha, A.K., Davis, T.E.: Geochemistry of Franciscan volcanic and sedimentary rocks from California. Carnegie Inst. Washington Yearb. 69, 394–400 (1971)
Spooner, C.M., Fairbairn, H.W.: Strontium 87/strontium 86 initial ratios in pyroxene granulite terranes. J. Geophys. Res. 75, 6706–6713 (1970)
Stacey, J.S., Kramers, J.D.: Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet. Sci. Lett. 26, 207–221 (1975)
Sun, S.S., Hanson, G.N.: Evolution of the mantle: Geochemical evidence from alkali basalts. Geology 3, 297–302 (1975)
Tanaka, T.: Geological significance of Rare Earth Elements in Japanese geosynclinal basalts. Contrib. Mineral. Petrol. 52, 233–246 (1975)
Tatsumoto, M., Knight, T.J., Allègre, C.J.: Time differences in the formation of meteorites as determined from the ratio of lead 207 to lead 206. Science 180, 1279–1283 (1973)
Taylor, H.P., Jr.: The oxygen isotope geochemistry of igneous rocks. Contrib. Mineral. Petrol. 19, 1–71
Taylor, H.P., Jr., Epstein, S.: Relationship between O18/O16 ratios in coexisting minerals of igneous and metamorphic rocks. Part I. Geol. Soc. Am. Bull. 73, 461–480 (1962)
Taylor, H.P., Jr., Forester, R.W.: Low-18 O igneous rocks from the intrusive complexes of Skye, Mull and Ardnamurchan, western Scotland. J. Petrol. 12, 465–497 (1971)
Taylor, H.P., Jr., Giannetti, B., Turi, B.: Oxygen isotope geochemistry of potassic igneous rocks from the Roccamonfina Volcano, Roman comagmatic region, Italy. Earth Planet. Sci. Lett. 46, 81–106 (1979)
Taylor, H.P., Jr., Silver, L.T.: Oxygen isotope relationships in plutonic igneous rocks of the Peninsular Ranges batholith, southern and Baja California. 4th Int. Conf. Geochron. Cosmochron. Isotope Geol. U.S. Geol. Survey Open File Rpt 78-701, 423–426 (1978)
Turekian, K.K., Wedepohl, K.H.: Distribution of the elements in some major units of the Earth's crust. Geol. Soc. Am. Bull. 72, 175–192 (1961)
Turi, B., Taylor, H.P., Jr.: Oxygen isotope studies of potassic volcanic rocks of the Roman Province, Central Italy. Contrib. Mineral. Petrol. 55, 1–31 (1976)
Velde, D.: Les lamprophyres à feldspath alcalin et biotite: minettes et roches voisines. Contrib. Mineral. Petrol. 30, 216–239 (1971)
Vitrac-Michard, A., Allègre, C.J.: A study of the formation and history of a piece of continental crust by 87Rb-87Sr method: the case of the french oriental Pyrenees. Contrib. Mineral. Petrol. 50, 257–285 (1975a)
Vitrac-Michard, A., Allègre, C.J.: 283U-206Pb, 235U-207Pb systematics on the Pyrenean basement. Contrib. Mineral. Petrol. 51, 205–212 (1975 b)
Vollmer, R.: Isotopic evidence for genetic relations between acid and alkaline rocks in Italy. Contrib. Mineral. Petrol. 60, 109–118 (1977)
Wilson, A.F., Green, D.C., Davidson, L.R.: The use of oxygen isotope geothermometry on granulites and related intrusives, Musgrave Ranges central Australia. Contrib. Mineral. Petrol. 27, 166–178 (1970)
Windley, B.F.: The evolving continents. London: Wiley 1977
Yoder, H.S., Tilley, C.E.: Origin of basalt magmas: an experimental study of natural and synthetic rock systems. J. Petrol. 3, 342–532 (1962)
Zartman, R.E., Wasserburg, G.J.: The isotopic composition of lead in potassium feldspars from some 1.0 b.y. old North American igneous rocks. Geochim. Cosmochim. Acta 33, 901–942 (1969)
Zwart, H.J.: On the determination of polymetamorphic mineral associations and its application to the Bosost area (Central Pyrenees). Geol. Rundschau 52, 38–65 (1962)
Author information
Authors and Affiliations
Additional information
Contribution Number 3280, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
Rights and permissions
About this article
Cite this article
Michard-Vitrac, A., Albarede, F., Dupuis, C. et al. The genesis of Variscan (Hercynian) plutonic rocks: Inferences from Sr, Pb, and O studies on the Maladeta igneous complex, central Pyrenees (Spain). Contrib. Mineral. Petrol. 72, 57–72 (1980). https://doi.org/10.1007/BF00375568
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00375568