Abstract
The Gil-Marquez Complex is an exceptional outcrop of plutonic rocks ranging in composition from diorites to granites emplaced into Devonian terrigenous metasediments of the southernmost part of the Hercynian basement of Iberia. A combined study of this complex, including field geology, petrology, structural geology and geochemistry, reveals that it represents an ancient conduit of magma transport through the continental crust. This conduit allowed the intrusion of magmas of contrasted compositions. Two end-members and several hybrids are identified. The first end-member is a biotite granite and the second is a basaltic magma generated by partial melting of a depletedmantle source. Both magmas rose through a common channel in which favorable conditions for unstable flow and magma mixing occurred. The observed relations in the Gil-Márquez Complex show that mixing in conduits may be an important mechanism for producing homogeneous hybrid magmas.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Arzi AA (1978) Critical phenomena in the theology of partially melted rocks. Tectonophysics 44:173–184
Baker DR (1989) Tracer versus trace element diffusion: diffusional decoupling of Sr concentration from Sr isotope composition. Geochim Cosmochim Acta 53:3015–3023
Baker DR (1991) Interdiffusion of hydrous dacitic and rhyolitic melts and the efficacy of rhyolite contamination of dacitic enclaves. Contrib Mineral Petrol 106:462–473
Blake S, Campell IH (1986) The dynamics of magma-mixing during flow in volcanic conduits. Contrib Mineral Petrol 94:72–81
Blundy JD, Holland TJB (1990) Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer. Contrib Mineral Petrol 104:208–224
Blundy JD, Sparks RSJ (1992) Petrogenesis of mafic inclusions in granitoids of the Adamello Massif, Italy. J Petrol 33:1039–1104
Bouchez JL, Delas C, Gleizes G, Nédélec A (1992) Submagmatic microfractures in granites. Geology 20:35–38
Campbell IH, Turner JS (1985) Turbulent mixing between fluids with different viscosities. Nature 313:39–42
Castro A, Moreno-Ventas I, De la Rosa JD (1990) Microgranular enclaves as indicators of hybridization processes in granitoid rocks, Hercynian belt, Spain. Geol J 25:391–404
Castro A, Moreno-Ventas I, De la Rosa JD (1991) H-type (hybrid) granitoids: a proposed revision of the granite type classification and nomenclature. Earth Sci Rev 31:237–253
Clemens JD, Mawer CK (1992) Granitic magma transport by fracture propagation. Tectonophysics 204:339–360
Crespo-Blanc A (1989) Evolución geotectónica del contacto entre la zona de Ossa-Morena y la Zona Surportuguesa en las Sierras de Aracena y Aroche (Macizo Ibérico Meridional): un contacto mayor en la Cadena Hercìnica Europea. Doctoral Thesis, Univ Sevilla, pp 1–560
De la Rosa JD (1992) Petrologìa de las rocks básicas y granitoides del batolito de la Sierra Norte de Sevilla, zona Surportuguesa, Macizo Ibérico. Doctoral Thesis, Univ Sevilla, pp 1–312
De la Rosa JD, Rogers G, Castro A (1993.) Relaciones 87Sr/86Sr de Rocas Básicas y Granitoides del batolito de la Sierra Norte de Sevilla. Rev Soc Geol Esp 6:141–149
Deer WA, Howie RA, Zussman J (1966) An Introduction to the Rock-forming Minerals. Longman, London, pp 1–528
Didier J, Barbarin B (1991) Granites and their Enclaves. 2nd edn. Elsevier, Amsterdam
Fernandez A, Gasquet D (1994) Relative theological evolution of chemically contrasted coeval magmas: example of the Tichka complex (Morocco) Contrib Mineral Petrol 116:316–326
Fourcade S, Allegre CJ (1981) Trace elements behavior in granite genesis: a case study the calc-alkaline plutonic association from the Querigut Complex (Pyrénées, France). Contrib Mineral Petrol 76:177–195
Garlick GD, Epstein S (1967) Oxygen isotope ratios in coexisting minerals of regionally metamorphosed rocks. Geochim Cosmochim Acta 31:181–214
Giese U, Glodny J, Kramm U. (1993) The Gil Marquez intrusion, SW Spain: syntectonic intrusion, magma-mixing and deformation in a transpressive regime. GSA Annual Meeting, Boston. Abstr Progr: A-342
Hoefs J (1987) Stable Isotope Geochemistry. Springer-Verlag, Berlin Heidelberg, pp 1–241
Huppert HE, Sparks RSJ, Turner JS (1982) Effects of volatiles on mixing in calc-alkaline magma systems. Nature 297:554–559
James DE (1981) The combined use of oxygen and radiogenic isotopes as indications of crustal contamination. Ann Rev Earth Planet Sci 9:311–344
John BE, Blundy JD (1993) Emplacement-related deformation of granitoid magmas, southern Adamello Massif, Italy. Bull Geol Soc Am 105:1517–1541
Johnson MC, Rutherford MJ (1989) Experimental calibration of the aluminum in hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks. Geology 17:837–841
Kouchi A, Sunagawa I (1985) A model for mixing basaltic and dacitic magmas as deduced from experimental data. Contrib Mineral Petrol 89:17–23
Koyaguchi T (1987) Magma mixing in a squeezed conduit. Earth Planet Sci Lett 84:339–344
Langmuir CH, Vocke RD Jr, Hanson GN, Hart SR (1978) A general mixing equation with applications to Icelandic basalts. Earth Planet Sci Lett 37:380–392
Leake BE (1978) Nomenclature of amphiboles. Can Mineral 16:501–520
Maaloe S, Wyllie PJ (1975) Water content of a granite magma deduced from the sequence of crystallization determined experimentally with water-undersaturated conditions. Contrib Mineral Petrol 52:175–191
Moreno-Ventas I, Rogers G, Castro A (1995) The role of hybridization in the genesis of Hercynian granitoids in the Gredos massif. Inferences from Sm/Nd isotopes. Contrib Mineral Petrol, in press
Nicholls IA, Harris KL (1980) Experimental rare earth partition coefficient for garnet, clinopyroxene and amphibole coexisting with andesitic and basaltic liquids. Geochim Cosmochim Acta 44:287–308
Paterson SR, Vernon RH, Tobisch OT (1989) A review of criteria for the identification of magmatic and tectonic foliations in granitoids. J Struct Geol 11:349–363
Recio C (1992) The late Hercynian granitoids of the western area of SCE: A stable (O, H, S) isotopic study. Doctoral Thesis, Univ Salamanca
Roscoe R (1952) The viscosity of suspensions of rigid spheres. J Appl Phys 3:267–269
Shaw HR (1980) The fracture mechanisms of magma transport from the mantle to the surface. Physics of Magmatic Processes. Princeton University Press, New York, pp 201–264
Sparks R, Marshall LA (1986) Thermal and mechanical constraints on mixing between mafic and silicic magmas. J Volcanol Geotherm Res 29:99–124
Spera FJ (1980) Aspects of magma transport. In: Hargraves, R (ed) Physics of Magmatic Processes. Princeton University Press, New York, pp 263–323
Taylor HP, Epstein S (1962) Relationship between 18O/16O ratios in coexisting minerals of igneous and metamorphic rocks. Geol Soc Am Bull 73:461–480
Ugidos JM, Fallick A, Recio C (1989) δ18O of granites from the Western Central Iberian Massif, Spain. Geogaceta 6:25–26
Vernon RH (1984) Microgranitoid enclaves in granite-globules of hybrid magma quenched in a plutonic environment. Nature 309:438–439
Vernon RH, Etheridge MA, Wall VJ (1988) Shape and microstructure of microgranitoid enclaves: indicators of magma mingling and flow. Lithos 22:1–11
Volmer R (1976) Rb-Sr and U-Th-Pb systematics of alkaline rocks: the alkaline rocks from Italy. Geochim Cosmochim Acta 40:283–295
Wyllie PJ (1977) Crustal anatexis: an experimental review. Tectonophysics 43:41–71
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Castro, A., De la Rosa, J.D., Fernández, C. et al. Unstable flow, magma mixing and magma-rock deformation in a deep-seated conduit: the Gil-Márquez Complex, south-west Spain. Geol Rundsch 84, 359–374 (1995). https://doi.org/10.1007/BF00260446
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00260446