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Basalts, underplated gabbros and pyroxenites record the rifting process of the West Iberian margin

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Summary

New petrological data on magmatic rocks obtained from the Iberia Abyssal Plain and from the Gorringe Bank, combined with those already known on the Galicia Bank, allow to better constrain the formation of the West Iberian Margin. These three zones were sampled along East-West transects of the ocean-continent transition, immediately West or at the foot of the last tilted continental block of the margin.

These sections expose similar lithological successions including scarce basalts, locally pillowed, resting directly on peridotites (predominant) which themselves include layers of pyroxenites and rare lenses of gabbros and gabbroic differentiates. The latter are locally strongly sheared and metamorphosed e.g. to chlorite schists.

At the Galicia Bank the exposed undepleted lherzolites are considered to be typical of a sub-continental lithospheric mantle environment. The mantle sections exposed at both the Iberia Abyssal Plain and the Gorringe Bank are clearly different. The presence of plagioclase-bearing websterite lenses and of small alkaline pyroxenites within the predominant harzburgites, is unknown in pure oceanic environments and supports their lithospheric sub-continental origin.

Along each transect, the mineralogy of the gabbroic series documents various depths of emplacement and deformation. The highest pressures near 0.8 GPa ( ∼ 24 km depth) at Galicia Bank and Iberia Abyssal Plain are estimated from Al-rich pyroxenes and from the occurrence of metamorphic spinels in the sheared gabbros (Iberia Abyssal Plain). These gabbros are interpreted as deriving from underplated magmas at the base of a slightly thinned continental crust. The lower pressures (≤ 0.6 GPa) registered in the Gorringe Bank gabbroic rocks and in some reexamined gabbros from the Galicia Bank, suggest the existence of successive intrusions during the stretching process.

The few basalts sampled on top of the exposed peridotites of the sea floor are inferred to be among the first post-rift extrusive magmas. They differ slightly from the North to the South of the margin: enriched and transitional tholeiites occur at Galicia Bank and in the Iberia Abyssal Plain, transitional and depleted tholeiites at the Gorringe Bank. The trace elements and the isotope data available show that the basalts and the gabbros derived from similar heterogeneous mantle sources (10.3 ≥ εNdT ≥ 3.6). The behavior of some incompatible elements (Nb in particular) documents locally either a possible fractionation of rutile in shallow lithospheric mantle or some contamination by the continental crust. A very slow lithospheric stretching, assisted by the intrusion, underplating, and the shearing of a few gabbroic sills, followed by the unroofing of heterogeneous subcontinental mantle can account for the formation of the entire West Iberian margin.

Résumé

De nouveaux résultats obtenus à partlr de l'étude des roches magmatiques dans la plaine Abyssale Ibérique et sur le Bane de Gorrlnge permettent avec ceux obtenus sur le Bane de Galice de mieux contraindre la formation de la marge Ouest Ibérique. Ces trois zones ont été échantillonnées selon des coupes Est-Ouest de la transition océan-continent, à partir du pied on immédiatement à l'Ouest des derniers blocs continentaux basculés.

La croûte de chacun de ces secteurs est composée de rares basaltes, localement en coussin, reposant directement sur des péridotites (prédominantes) qui elles-mêmes contiennent des niveaux de pyroxénites et de rares lentilles de gabbros localement différenciés. Ces derniers sont souvent fortement cisaillés et métamorphises et parfois transformés en schistes chloriteux.

Les péridotites fertiles (lherzolites) du Bane de Gallce sont considérées comme représentatives d'un manteau lithosphérique sous-continental. Cette origine est étendue aux sections mantelliques à dominante harzburgitique de la plaine Abyssale Ibérique et du Bane de Gorringe. En effet elles exposent de rares pyroxénites alcalines et d'abondantes lentilles de webstérite à plagioclase, inconnues en domaine purement océanique.

La minéralogie des séries gabbroïques indique des conditions variées de mise en place des magmas. Les pyroxènes riches en aluminium du Bane de Galice et de la Plaine Abyssale Ibérique et la présence locale de spinelle dans les gabbros cisaillés (Plaine Abyssale Ibérique) supposent une cristallisation sous des pressions proches de 0.8 GPa ( ∼ profondeur de 24 km). Ces gabbros ne peuvent done pas avoir cristallisé sous une croûte océanique normale et sont interprétés comme provenant de magmas sous-plaqués à la base d'une croûte continentale faiblement amincie. Quelques gabbros du Bane de Gallce et ceux du Bane de Gorringe ont enregistré des conditions de cristallisation plus superficielles (à molns de 18 km), donc au sein de péridotites situées sous une croûte continentale plus mince ou inexistante. Dans un processus d'étirement crustal la mlse en place de ces gabbros apparaît ainsi échelonnée avec des venues précoces dans le cas de la Plaine Abyssale Ibérique et plus tardives dans le cas du Banc de Gorringe.

Les basaltes reposant directement sur les péridotites du fond océanique correspondent aux premiers magmas extrusifs post-rift. Ils different sensiblement du Nord au Sud de la marge: depuis des tholeiites enrichies et transitionnelles exposees sur le Banc de Gallce et dans la Plaine Abyssale Ibérique, jusqu' à des tholeiites transitionnelles et appauvries sur le Banc de Gorringe. Les éléments traces et les données isotopiques disponibles montrent que les basaltes et les gabbros dérivent de sources mantelliques similaires et hétérogènes (10.3 ≥ εNdT ≥ 3.6). Le comportement de quelques éléments incompatibles (Nb en particulier) témoigne localement d'un possible fractionnement de rutile à faible profondeur dans le manteau lithosphérique on d'une contamination par de la croûte continentale. Un amincissement lithosphérique très lent, partiellement aidé par l'injection, le sous-plaquage et le cisaillement de quelques sills de gabbro et suivi de la dénudation d'un manteau sous-continental hétérogène, rend compte de la formation de l'ensemble de la marge Ouest Ibérique.

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References

  • Agrinier P, Mével C, Girardeau J (1988) Hydrothermal alteration of the peridotites cored at the ocean/continent boundary of the Iberian margin: petrologic and stable isotope evidence. Proc Ocean Drill Program Sci Results 103: 225–234

    Google Scholar 

  • Agrinier P, Mevel C, Bosch D, Javoy M (1993) Metasomatic hydrous fluids in amphibole peridotites from Zabargad Island (Red Sea). Earth Planet Sci Lett 120: 187–205

    Google Scholar 

  • Alibert C (1985) A Sr-Nd isotope and REE study of late Triassic dolerites from the Pyrenees (France) and the Messejana Dyke (Spain and Portugal). Earth Planet Sci Lett 73: 81–90

    Google Scholar 

  • Al'mukhamedov AI, Sborshikov IM, Lobkoskiy LI (1991) New data on the structure of the Gorringe ridge in the North Atlantic. Trans USSR Acad Sci Earth Sci (Doklady) 309: 131–133

    Google Scholar 

  • Aoki K, Shiba I (1973) Pyroxenes from lherzolite inclusions of Itinome-gata, Japan. Lithos 6: 41–51

    Google Scholar 

  • Arai S, Matsukage K, Isobe E, Vysotskiy S (1997) Concentration of incompatible elements in oceanic mantle: effect of melt/wall interaction in stagnant or failed melt conduits within peridotite. Geochim Cosmochim Acta 61: 671–675

    Google Scholar 

  • Arndt NT, Czamanske GK, Wooden JL, Fedorenko VA (1993) Mantle and crustal contributions to continental flood volcanism. Tectonophysics 223: 39–52

    Google Scholar 

  • Auzende J-M, Olivet J-M, Charvet J, Le Lann A, Le Pichon X, Monteiro JH, Nicolas A, Ribeiro A (1978) Sampling and observation of mantle and crust on Gorringe Bank. Nature 273: 45–49

    Google Scholar 

  • Auzende J-M, Charvet J, Le Lann A, Le Pichon X, Monteiro JH, Nicolas A, Olivet J-M, Ribeiro A (1979) Le Bane de Gorringe: resultats de la campagne CYAGOR (Août 1977). Bull Soc Geot fr XXI 5: 545–556

    Google Scholar 

  • Benoit M, Polve M, Ceuleneer G (1996) Trace element and isotopic characterization of mafic cumulates in a fossil mantle diapir (Oman Ophiolite). Chem Geol 134: 199–214

    Google Scholar 

  • Bernard-Griffith J, Gruau G, Cornen G, Azambre B, Macé J (1997) Continental lithospheric contribution to alkaline magmatism: isotopic (Nd, Sr, Pb) and geochemical (REE) evidence from Serra de Monchique and Mount Ormonde complexes. J Petrol 38: 115–132

    Google Scholar 

  • Bertrand H, Dostal J, Dupuy C (1982) Geochemistry of early mesozoic tholeiites from Morocco. Earth Planet Sci Lett 58: 225–239

    Google Scholar 

  • Beslier M-O, Girardeau J, Boillot G (1990) Structure and kinematics of emplacement of peridotites uplifted during continental rifting: results of the Galinaute dives on Galicia margin (Spain). Tectonophysics 184: 321–343

    Google Scholar 

  • Beslier M-O, Ask M, Boillot G (1993) Ocean-continent boundary in the Iberia Abyssal Plain from multichannel seismic data. Tectonophysics 218: 0383–393

    Google Scholar 

  • Bloomer SH, Natland JH, Fisher RJ (1989) Mineral relationships in gabbroic rocks from fracture zones of Indian Ocean ridges: evidence for extensive fractionation, parental diversity and boundary-layer recrystallization. In:Saunders AD, Norry MJ (eds) Magmatism in the ocean basins. Geol Soc Sp Publ 42: 107–124

  • Bodinier JL (1989) Distribution des Terres Rares dans le Massif de Lanzo et de l'Ariege. Doc and Trav CGG Montpellier 22, 177pp

  • Bodinier JL, Lorand JP, Dostal J, Dupuy C (1987) Geochemistry of amphibole pyroxenite veins from the Lherz and Freychinède ultramafic bodies (Ariege, French Pyrenees). Bull Mineral 110: 345–358

    Google Scholar 

  • Boillot, G;Grimaud S, Mauffret A, Mougenot D, Kornprobst J (1980) Ocean-continent boundary off the Iberia margin: a serpentinite diapir west of the Galicia Bank. Earth Planet Sci Lett 48: 23–34

    Google Scholar 

  • Boillot G, Girardeau J, Kornprobst J (1988) The rifting of the Galicia margin: crustal thinning and emplacement of mantle rocks on the sea floor. Proc Ocean Drill Program Sci Results 103: 741–756

    Google Scholar 

  • Boillot, G, Agrinier P, Beslier M-O, Cornen G, Froitzheim N, Gardien V, Girardeau J, GilIbarguchi J-I, Kornprobst J, Moullade M, Schdrer U, Vanney J-R (1995) A lithospheric syn-rift shear zone at the ocean-continent transition: preliminary results of the Galinaute II cruise (Nautile dives on the Galicia Bank, Spain). CR Acad Sci Paris, 321, IIa: 1171–1178

    Google Scholar 

  • Bonatti F, Michael PJ (1989) Mantle peridotites from continental rifts to ocean basins to subduction zones. Earth Planet Sci Lett 91: 297–311

    Google Scholar 

  • Bonatti E, Seyler M (1987) Crustal underplating and evolution in the Red Sea rift; uplifted gabbro/gneiss crustal complexes on Zabargad and Brothers islands. J Geophys Res 92 12,803–12,821

    Google Scholar 

  • Boudier F, Nicolas A, Ji S, Kienast JR, Mevel C (1988) The gneiss of Zabargad Island: deep crust of a rift. Tectonophysics 150: 209–227

    Google Scholar 

  • Bougault H, Joron JL, Treuil M, Maury R (1985) Local versus regional mantle heterogeneities: evidence from hygromagmaphile elements. Proc Ocean Drill Program Initial Rep 82: 459–482

    Google Scholar 

  • Cannat M, Seyler M (1995) Transform tectonics, metamorphic plagioclase and amphibolitization in ultramafic rocks of the Vema transform fault (Atlantic Ocean). Earth Planet Sci Lett 133: 283–298

    Google Scholar 

  • Charpentier S, Kornprobst J, Chazot G, Cornen G, Boillot G (1998) Interaction entre lithosphére et asthénosphère an cours de l'ouverture océanique: données isotopiques préliminaires sur la marge passive de Galice (Atlantique-Nord). CR Acad Sci Paris 326: 757–762

    Google Scholar 

  • Comas MC, Sänchez-Gómez M, Cornen G, de Kaenel E (1996) Serpentinized peridotite breccia and olistostrome on basement highs of the Iberia Abyssal Plain: implications for tectonic margin evolution. Proc Ocean Drill Program Sci Results 149: 577–591

    Google Scholar 

  • Cornen G (1982) Petrology of the alkaline volcanism of Gorringe Bank (Southwest Portugal). Marine Geol 47: 101–130

    Google Scholar 

  • Cornen G, Beslier M-O, Girardeau J (1996) Petrologic characteristics of the ultramafic rocks from the Ocean/continent transition in the Iberia Abyssal Plain. Proc Ocean Drill Program Sci Results 149, 21: 377-395

    Google Scholar 

  • Cotten J, Le Dez A, Bau M, Caroff M, Maury RC, Dulski P, Fourcade S, Bohn M, Brousse R (1995) Origin of anomalous rare-earth element and yttrium enrichments in subaerially exposed basalts: evidence from French Polynesia. Chem Geol 119: 115–138

    Google Scholar 

  • Cyagor I Group (1979) Campagne CYAGOR 25 Juillet-26 Août 1977 Résultats des campagnes à la mer. Pub CNEXO 17, 75pp

  • Cyagor II Group (1984a) Géologie du Banc de Gorringe Campagne GYAGOR 11 25 Mai-18 Juin 1981 Résultats des campagnes à la mer. Pub CNEXO 27, 73pp

  • Cyagor II Group (1984b) Intraoceanic tectonism of the Gorringe Bank: observation by submersible. In:Gass JG, Lippard SJ, Shelton AW (eds) Ophiolite and oceanic lithosphere. Geol Soc London, Spec Public, pp 113–120

  • Dautria JM, Liotard JM, Cabanes N, Girod M, Briqueu L (1987) Amphibole-rich xenoliths and host alkali basalts: petrogenetic constraints and implications on the recent evolution of the upper mantle beneath Ahaggar (Central Sahara, Southern Algeria). Contrib Mineral Petrol 95: 133–144

    Google Scholar 

  • Dick HJB, Bullen T (1984) Chromian spinel as a petrogenetic indicator in abyssal and alpine type peridotites and spatially associated lavas. Contrib Mineral Petrol 86: 54–76

    Google Scholar 

  • Dosso L, Bougault H, Joron JL (1993) Geochemical morphology of the North Mid-Atlantic ridge, 10–24°N: trace element-isotope complementarity. Earth Planet Sci Lett 120: 443–462

    Google Scholar 

  • Dupuy C, Dostal J (1984) Trace element geochemistry of some continental tholeiites. Earth Planet Sci Lett 67: 61–69

    Google Scholar 

  • Ellam RM (1992) Lithospheric thickness as a control on basalt geochemistry. Geology 20: 153–156

    Google Scholar 

  • Essaifi A, Capdevila R, Lagarde JL (1995) Transformation de leucogabbros en chloritoschistes sous l'effet de l'altération hydrothermale et de la déformation dans l'intrusion de Kettara (Jebilet, Maroc). CR Acad Sci Paris, 320, IIa: 189–196

    Google Scholar 

  • Evans CA, Girardeau J (1988) Galicia margin peridotites: undepleted abyssal peridotites from the North Atlantic. Proc Ocean Drill Program Sci Results 103: 195–207

    Google Scholar 

  • Féraud G, Gastaud J, Auzende J-M, Olivet JL, Cornen G (1982)40Ar-39Ar ages for the alkaline volcanism and basement of the Gorringe Bank, North Atlantic Ocean. Earth Planet Sci Lett 57: 211–226

    Google Scholar 

  • Féraud G, York D, Mevel C, Cornen G, Auzende J-M (1986) Additionnal40Ar-39Ar dating of the basement and alkaline volcanism of the Gorringe Bank (Atlantic Ocean). Earth Planet Sci Lett 79: 255–269

    Google Scholar 

  • Féraud G, Girardeau J, Beslier M-O, Boillot G (1988) Datations40Ar-39Ar de la mise en place des péridotites bordant la marge de Galice (Espagne). CR Acad Sci Paris 11, 307: 49-55

    Google Scholar 

  • Féraud G, Beslier M-O, Cornen G (1996)40Ar-39Ar dating of gabbros from the ocean/continent transition of the West Iberia margin: preliminary results. Proc Ocean Drill Program Sci Results 149: 489–495

    Google Scholar 

  • Frost BR (1991) Stability of oxide minerals in metamorphic rocks. In:Lindsley DH (ed) Oxides minerals, petrologic and magnetic significance. Min Soc Am, Paul H Ribbe Ser, 25: 469–487

  • Fram MS, Lesher CE, Volpe AM (1998) Mantle melting, systematics: transition from continental to oceanic volcanism on the southeast Greenland margin. Proc Ocean Drill Program Sci Results 152: 373–386

    Google Scholar 

  • Froitzheim N, Manatschal G (1996) Kinematics of Jurassic rifting, mantle exhumation, and passive margin formation in the Austroalpine and Penninic nappes (eastern Switzerland). Geol Soc Am Bull 108, 9: 1120–1133

    Google Scholar 

  • Gavasci AT, Fox PJ, Ryan WBF (1973) Petrography of rocks from the crestal area of the Gorringe Bank. Proc Deep Sea Drill Program Initial Rep 13: 749–752

    Google Scholar 

  • Girardeau J, Evans CA, Beslier M-O (1988) Structural analysis of plagioclase-bearing peridotites emplaced at the end of continental rifting: Hole 637A, ODP Leg 103 on the Galicia Margin. Proc Ocean Drill Program Sci Results 103: 209–223

    Google Scholar 

  • Girardeau J, Cornen G, Agrinier P, Beslier M-O, Dubuisson G, Le Gall B, Monnier C, Pinheiro L, Ribeiro A, Whitechurch H (1998) Premiers resultats des plongees du Nautile sur le bane de Gorringe (Quest Portugal). CR Acad Sci Paris 326: 247–254

    Google Scholar 

  • Hébert R, Constantin M, Robinson PT (1991) Primary mineralogy of Leg 118 gabbroic rocks and their place in the spectrum of oceanic mafic igneous rocks. Proc Ocean Drill Program Sci Results 118: 3–20

    Google Scholar 

  • Helmstaedt H, Allen JM (1977) Metagabbronorite from DSDP Hole 334: an example of high-temperature deformation and recrystallization near the Mid-Atlantic Ridge. Can J Earth Sci 14: 886–898

    Google Scholar 

  • Holland T, Bluntly J (1994) Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry. Contrib Mineral Petrol 116: 453–447

    Google Scholar 

  • Honnorez J, Fox PJ (1973) Petrography of the Gorringe Bank ‘basement’. Proc Deep Sea Drill Program Initial Rep 13: 747–749

    Google Scholar 

  • Honnore J, Mevel C, Montigny R (1984) Geotectonic significance of gneissic amphibolites from the Vema fracture Zone, Equatorial Mid-Atlantic Ridge. J Geophys Res 89: 11,379–11,400

    Google Scholar 

  • Ionov DA, Hofmann AW (1995) Nb-Ta-rich mantle amphiboles and micas: implications for subduction-related metasomatic trace element fractionations. Earth Planet Sci Lett 131: 341–356

    Google Scholar 

  • Irving AJ, Frey FA (1984) Trace element abundances in megacrysts and their host basalts: constraints on partition coefficients and megacryst genesis. Geochim Cosmochim Acta 48: 1201–1221

    Google Scholar 

  • Ito E, Anderson AT Jr (1983) Submarine metamorphism of gabbros from the Mid-Cayman Rise: petrographic and mineralogy constraints on hydrothermal processes at slowspreading ridges. Contrib Mineral Petrol 82: 371–388

    Google Scholar 

  • Komprobst J, Tabit A (1988) Plagioclase bearing ultramafic tectonites from the Galicia margin (Leg 103 Site 637): comparison of their origin and evolution with low-pressure ultramafic bodies in Western Europe. Proc Ocean Drill Program Sci Results 103: 253–268

    Google Scholar 

  • Kornprobst J, Vidal P, Malod J (1988) Les basaltes de la marge de Galice (NO de la Peninsule Ibérique): hétérogénéite des spectres de terres rares à la transition continent/ocean. Donnees geochimiques preliminaires. CR Acad Sci fr 306, 11: 1359–1364

    Google Scholar 

  • Lécuyer C, Brouxel M, Lapierre H (1991) Petrogenesis of magmas at a fossil slow-spreading center: the Trinity ophiolite (northern California, USA). Bull Soc Geol fr 162: 795–809

    Google Scholar 

  • Louden KE, Sibuet JC, Harmegnies F (1997) Variations in heat flow across the ocean-continent transition in the Iberia abyssal plain. Earth Planet Sci Lett 151: 233–254

    Google Scholar 

  • Mével C (1984) Le métamorphisme dans la croûte océanique: apport de la pétrologie à la compréhension des phénomènes de circulation hydrothermale et de déformation. Université P et M Curie, Paris, 434pp

  • Mével C (1988) Metamorphism in oceanic layer 3, Gorringe Bank, Eastern Atlantic. Contrib Mineral Petrol 100: 496–509

    Google Scholar 

  • Montigny R (1975) Géochimie comparée des roches océaniques et ophiolitiques. Problèmes de leur genèse. Univ Paris 6 and 7, Paris, 288pp ODP Leg 149 Shipboard Scientific party (1994) Sites 897, 899, 900. Proc Ocean Drill Program Initial Rep 149: 41-268

  • ODP Leg 152 Shipboard Scientific party (1994) Site 917. Proc Ocean Drill Program Initial Rep 152: 107–158

    Google Scholar 

  • ODP Leg 163 Shipboard Scientific party (1996) Site 988. Proc Ocean Drill Program Initial Rep 163: 23–30

    Google Scholar 

  • Olivet J-L (1996) La cinématique de la plaque Ibérique. Bull Centres Rech Explor Prod Elf Aquitaine 20: 131–195

    Google Scholar 

  • Papezik VS, Hodych JP (1980) Early Mesozoic diabase dikes of the Avalon Peninsula, Newfoundland: petrochemistry, mineralogy and origin. Can J Earth Sci 17: 1417–1430

    Google Scholar 

  • Pedersen RB, Malpas J (1984) The origin of oceanic plagiogranites from the Karmoy ophiolite, Western Norway. Contrib Mineral Petrol 88: 36–52

    Google Scholar 

  • Petrini R, Joron JL, Ottonello G, Bonatti E, Seyler M (1988) Basaltic dykes from Zabargad island, Red Sea: petrology and geochemistry. Tectonophysics 150: 229–248

    Google Scholar 

  • Piccardo GB, Messiga B, Vannucci R (1988a) The Zabargad peridotite-pyroxenite association: petrological constraints on its evolution. Tectonophysics 150: 209–227

    Google Scholar 

  • Piccardo GB, Rampona E, Scambellori M (1988b) The Alpine evolution of the Erro-Tobbio peridotites (Voltri massif, Ligurian Alps); some field and petrographic constraints. Ofioliti 13: 169–174

    Google Scholar 

  • Pickup SLB, Whitmarsh RB, Fowler CMR, Reston TJ (1996) Insight into the nature of the ocean-continent transition off West Iberia from a deep multichannel seismic reflection profile. Geology 24: 1070–1082

    Google Scholar 

  • Prichard H, Cann JR (1982) Petrology and mineralogy of dredged gabbro from Gettysburg Bank, Eastern Atlantic. Contrib Mineral Petrol 79: 46–55

    Google Scholar 

  • Prichard H, Mitchell JG (1979) K-Ar data for the age and evolution of Gettysburg Bank, North Atlantic Ocean. Earth Planet Sci Lett 44: 261–268

    Google Scholar 

  • Remaidi M (1993) Etude pétrologique et géochimique d'une association péridotites réfractaires-pyroxénites dans le massif de Ronda (Espagne). Thesis, Univ of Montpellier, France, 437pp

  • Rudnick R, Fountain DM (1995) Nature and composition of the continental crust; a lower crustal perspective. Geophys Rev 33: 267–309

    Google Scholar 

  • Schärer U, Kornprobst J, Beslier M-O, Boillot G, Girardeau J (1995) Gabbro and related rock emplacement beneath rifting continental crust: U-Pb geochronological and geochemical constraints for the Galicia passive margin (Spain). Earth Planet Sci Lett 130: 187–200

    Google Scholar 

  • Schmidt MW (1992) Amphibole composition in tonalite as a fonction of pressure: an experimental calibration of the Al-in-hornblende barometer. Contrib Mineral Petrol 110: 304–310

    Google Scholar 

  • Sebai A, Féraud G, Bertrand H, Hanes J (1991)40Ar-39Ar dating and geochemistry of tholeiitic magmatism related to the early opening of the Central Atlantic rift. Earth Planet Sci Lett 104: 455–472

    Google Scholar 

  • Seifert K, Brunotte D (1996) Geochemistry of serpentinized mantle peridotite from Site 897 in the Iberia Abyssal Plain. Proc Ocean Drill Program Sci Results 149: 413–424

    Google Scholar 

  • Seifert K, Gibson I, Weis D, Brunotte D (1996) Geochemistry of metamorphosed cumulate gabbros from Hole 900A, Iberia Abyssal Plain. Proc Ocean Drill Program Sci Results 149: 471–485

    Google Scholar 

  • Serri G, Hebert R, Hekinian R (1988) Petrology of a plagioclase-bearing olivine websterite from Gorringe Bank (northeastern Atlantic Ocean). Can J Earth Sci 25: 557–569

    Google Scholar 

  • Seyler M, Bonatti E (1994) Na, AlIV and AlVI in clinopyroxenes of subcontinental and suboceanic ridge peridotites: a clue to different melting processes in the mantle? Earth Planet Sci Lett 122: 281–289

    Google Scholar 

  • Sun S-s, McDonough WF (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In:Saunders AD, Norry MJ (eds) Magmatism in the ocean basins. Geol Soc Sp Pub 42: 313–342

  • Sweeney RJ, Thompson AB, Ulmer P (1993) Phase relations of a natural MARID composition and implications for MARID genesis, lithospheric melting and mantle metasomatism. Contrib Mineral Petrol 115: 225–241

    Google Scholar 

  • Tarney J, Saunders AD, Weaver SD, Donnellan NCB, Hendry GL (1978) Minor element geochemistry of basalts from Leg 49, North Atlantic Ocean. Proc Deep Sea Drill Program Initial Rep 49: 657–691

    Google Scholar 

  • Tiezzi LJ, Scott RB (1980) Crystal fractionation in a cumulate gabbro, Mid Atlantic ridge, 26°N, J Geophys Res 85: 5438–5454

    Google Scholar 

  • Tribuzio R, Messiga B, Vannucci R, Bottazzi P (1996) Rare earth element redistribution during high-pressure-low-temperature metamorphism in ophiolitec Fe-gabbros (Liguria, northwestern Italy): implications for light REE mobility in subduction zones. Geology 24: 711–714

    Google Scholar 

  • Weaver BL, Tarney J, Saunders AD (1985) Geochemistry and mineralogy of basalts recovered from the Central North Atlantic. Proc ODP Init Repts 82: 395–419

    Google Scholar 

  • White WM, Hofmann AW (1982) Sr and Nd isotope geochemistry of oceanic basalts and mantle evolution. Nature 296: 821–825

    Google Scholar 

  • Whitmarsh RB, Miles PR, Mauffret A (1990) The ocean-continent boundary off the western continental margin of Iberia I Crustal structure at 40° 30° N. Geophys J Intern 103: 509–531

    Google Scholar 

  • Whitmarsh RB, Pinheiro LM, Miles PR, Recq M, Sibuet J-C (1993) Thin crust at the western Iberia ocean-continent transition and ophiolites. Tectonics 12: 1230–1239

    Google Scholar 

  • Whitmarsh RB, Sawyer DS, Klaus A et al. (1996) Proc ODP Init Repts 149, 403pp

  • Whitmarsh RB, Beslier M-O, Wallace PJ et al. (1998) Proc ODP Init Repts 173, 403pp

  • Whitney PR (1972) Spinel inclusions in plagioclase of metagabbros from Adirondack Highlands. Am Mineral 57: 1429–1436

    Google Scholar 

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  1. Faculté des Sciences et Techniques, Laboratoire de Pétrologie Structurale, 2 rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 2, France

    G. Cornen, J. Girardeau & C. Monnier

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Cornen, G., Girardeau, J. & Monnier, C. Basalts, underplated gabbros and pyroxenites record the rifting process of the West Iberian margin. Mineralogy and Petrology 67, 111–142 (1999). https://doi.org/10.1007/BF01161518

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