Variscan eclogites from the Argentera–Mercantour Massif (External Crystalline Massifs, SW Alps): a dismembered cryptic suture zone

Abstract

We document structural, geochemical, petrological and 40Ar/39Ar geochronological data performed on Variscan eclogites from the Argentera–Mercantour Massif, southwestern Alps. Based on the high-resolution field mapping, we present new eclogite occurrences and discuss the relationships between eclogites and surrounding migmatites. We recognized for the first time preserved eclogite facies assemblages. Trace elements and REE patterns establish that eclogites protoliths are MORBs contaminated by continental crust. Standard thermobarometry and thermodynamic modeling are consistent with PT values of 640–740 °C for 1.5 ± 0.25 GPa, coherent with paleo-geotherms predicted for warm subduction of oceanic crust. We interpret these eclogites as a dismembered cryptic suture zone. 40Ar/39Ar dating on amphiboles yields an age of 339.7 ± 12 Ma for eclogite retrogression under amphibolite facies conditions. All these data are combined to link the Argentera–Mercantour Massif in the tectonic framework of both pre-Mesozoic Alpine basement and European southern Variscides.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13:
Fig. 14

References

  1. Ballèvre M, Bosse V, Ducassou C, Pitra P (2009) Palaeozoic history of the Armorican Massif: models for the tectonic evolution of the suture zones. C R Geosci 341:174–201

    Article  Google Scholar 

  2. Bard JP, Caruba C (1982) Texture et minéralogie d’une éclogite à disthène-saphirine-hypersténe-quartz en inclusion dans les gneiss migmatitites des Cavaliéres, massif de Ste Maxime (Maures, Var, France). C R Acad Sci Paris 294:103–106

    Google Scholar 

  3. Berger J, Féménias O, Ohnenstetter D, Bruguier O, Plissart G, Mercier JC, Demaiffe D (2010) New occurrence of UHP eclogites in Limousin (French Massif Central): age, tectonic setting and fluid–rock interactions. Lithos 118:365–382

    Article  Google Scholar 

  4. Blasi A (1971) Genesi dei noduli a sillimanite nelle anatessiti del Mt. Pélago (Alpi Marittime) in rapporto ai fenomeni di metamorfismo, piegamento e granitizzazione. Mem Soc Geol It 10:167–190

    Google Scholar 

  5. Blasi A, Schiavinato G (1968) Significato petrologico dei noduli a sillimanite e dei noduli a cordierite diffusi nelle anatessiti biotitiche del M. Pelago (massiccio cristallino dell’Argentera). Boll Soc Geol It 87:253–275

    Google Scholar 

  6. Bogdanoff S, Michard A, Mansour M, Poupeau G (2000) Apatite fission track analysis in the Argentera massif: evidence of contrasting denudation rates in the External Crystalline Massifs of the Western Alps. Terra Nova 12:117–125

    Article  Google Scholar 

  7. Bogdanoff S, Ménot RP, Vivier G (1991) Les massifs cristallins externes des alpes occidentales françaises, un fragment de la zone interne varisque. Sci Géol Bull 44:237–283

    Google Scholar 

  8. Bogdanoff S, Ploquin A (1980) Les gneiss et migmatites du massif de l’Argentera (Alpes maritimes); apport de deux coupes geochimiques. Bull Soc géol Fr 7:353–358

    Article  Google Scholar 

  9. Boland JN, Van Roermund HLM (1983) Mechanisms of exsolution in omphacites from high temperature, type B, eclogites. Phys Chem Miner 9:30–37

    Article  Google Scholar 

  10. Bortolami G, Sacchi R (1968) Osservazioni geologico-petrografiche sui medi valloni di S.Anna e Rio Freddo (Massiccio Cristallino dell'Argentera). Mem Soc Geol It 7:37–64

    Google Scholar 

  11. Boucarut M (1967) Structure du granite de l’Argentera et style tectonique de l’ensemble de ce massif. C R Acad Sci Paris 264:1573–1576

    Google Scholar 

  12. Briand B, Bouchardon JL, Capiez P, Piboule M (2002) Felsic (A-type)-basic (plume-induced) early palaeozoic bimodal magmatism in the Maures massif (southeastern France). Geol Mag 139:291–311

    Article  Google Scholar 

  13. Carlson RW (2003) Treatise on geochemistry. Geochemistry of the mantle and core, vol 2. Elsevier

  14. Carmignani L, Carosi R, Di Pisa A, Gattiglio M, Musumeci G, Oggiano G, Pertusati PC (1994) The Hercynianchain in Sardinia (Italy). Geodin Acta 7:31–47

    Article  Google Scholar 

  15. Carosi R, D’Addario E, Mammoliti E, Montomoli C, Simonetti M (2016) Geology of the northwestern portion of the Ferriere–Mollieres Shear Zone, Argentera Massif Italy. J Maps 12(sup1):466–475

    Article  Google Scholar 

  16. Carosi R, Frassi C, Montomoli C (2009) Deformation during exhumation of medium-and high-grade metamorphic rocks in the Variscan chain in northern Sardinia (Italy). Geol J 44:280–305

    Google Scholar 

  17. Carosi R, Oggiano G (2002) Transpressional deformation in NW Sardinia (Italy): insights on the tectonic evolution of the Variscan belt. C R Geosci 334:273–278

    Article  Google Scholar 

  18. Carosi R, Di Pisa A, Iacopini D, Montomoli C, Oggiano G (2004) The structural evolution of the Asinara Island (NW Sardinia, Italy). Geodin Acta 17:309–329

    Article  Google Scholar 

  19. Carswell DA, Wilson RN, Zhai M (2000) Metamorphic evolution, mineral chemistry and thermobarometry of schists and orthogneisses hosting ultra-high pressure eclogites in the Dabieshan of central China. Lithos 52:121–155

    Article  Google Scholar 

  20. Cloos M (1993) Lithospheric buoyancy and collisional orogenesis: subduction of oceanic plateaus, continental margins, island arcs, spreading ridges, and seamounts. Geol Soc Am Bull 105:715–737

    Article  Google Scholar 

  21. Cocks LRM, Torsvik TH (2011) The Palaeozoic geography of Laurentia and western Laurussia: a stable craton with mobile margins. Earth Sci Rev 106:1–51

    Article  Google Scholar 

  22. Coggon R, Holland JB (2002) Mixing properties of phengitic micas and revised garnetphengite thermobarometers. J Metamorph Geol 20:683–696

    Article  Google Scholar 

  23. Coleman RG, Lee DE, Beatty LB, Brannock WW (1965) Eclogites and eclogites—their differences and similarities. Geol Soc Am Bull 76:483–508

    Article  Google Scholar 

  24. Colombo F, Compagnoni R, Lombardo B (1994) Le rocce eclogitiche dei Laghi del Frisson (Argentera sud-orientale, Alpi Marittime). Atti Tic Sci Terra Serie Spec 1:75–82

    Google Scholar 

  25. Compagnoni R, Ferrando S, Lombardo B, Radulesco N, Rubatto D (2010) Paleo-European crust of the Italian Western Alps: geological history of the Argentera Massif and comparison with Mont Blanc-Aiguilles Rouges and Maures–Tanneron Massifs. J Virt Explor 36:3

    Google Scholar 

  26. Corsin P, Faure-Muret A (1946) Découverte d’une florule stéphanienne au cirque de Férisson près de Saint-Martin Vésubie (Alpes Maritimes). C R Somm Soc Géol Fr 256–257

  27. Corsin P, Faure-Muret A (1951) Nouvelle flore du Stéphanien à l’est de Saint-Martin Vésubie (Alpes Maritimes). C R Somm Soc Géol Fr 57–58

  28. Corsini M, Bosse V, Féraud G, Demoux A, Crevola G (2010) Exhumation processes during post-collisional stage in the Variscan belt revealed by detailed 40Ar/39Ar study (Tanneron massif, SE France). Int J Earth Sci 96:1–9

    Google Scholar 

  29. Corsini M, Rolland Y (2009) Late evolution of the southern European Variscan belt: exhumation of the lower crust in a context of oblique convergence. C R Geosci 341:214–223

    Article  Google Scholar 

  30. Corsini M, Ruffet G, Caby R (2004) Alpine and late-Hercynian geochronological constrains in the Argentera Massif (Western Alps). Eclogae Geol Helv 97:3–15

    Article  Google Scholar 

  31. Cruciani G, Franceschelli M, Groppo C (2011) P-T evolution of eclogite-facies metabasite from NE Sardinia, Italy: insights into the prograde evolution of Variscan eclogites. Lithos 121:135–150

    Article  Google Scholar 

  32. Cruciani G, Franceschelli M, Groppo C, Oggiano G, Spano ME (2015) Re-equilibration history and P–T path of eclogites from Variscan Sardinia, Italy: a case study from the medium-grade metamorphic complex. Int J Earth Sci 104:797–814

    Article  Google Scholar 

  33. Cruciani G, Franceschelli M, Langone A, Puxedd M, Scodina M (2017) Nature and age of pre-Variscan eclogite protoliths from the Low- to Medium-Grade Metamorphic Complex of north-central Sardinia (Italy) and comparisons with coeval Sardinian eclogites in the northern Gondwana context. J Geol Soc 172:792–807

    Article  Google Scholar 

  34. Dale J, Holland TJB (2003) Geothermobarometry, PT paths and metamorphic field gradients of high-pressure rocks from the Adula Nappe, Central Alps. J Metamorph Geol 21(8):813–829

    Article  Google Scholar 

  35. De Capitani C, Petrakakis K (2010) The computation of equilibrium assemblage diagrams with Theriak/Domino software. Am Min 95:1006–1016

    Article  Google Scholar 

  36. Debon F, Lemmet M (1999) Evolution of Mg/Fe ratios in late Variscan plutonic rocks from the external crystalline massifs of the Alps (France, Italy, Switzerland). J Petrol 40(7):1151–1185

    Article  Google Scholar 

  37. Demoux A, Schärer U, Corsini M (2008) Variscan evolution of the Tanneron massif, SE-France, examined through U-Pb monazite ages. J Geol Soc 165:467–478

    Article  Google Scholar 

  38. Di Paola S (2001) Eredità litostratigrafica, strutturale e metamorfica paleozoica nel margine interno Europeo (Grandes Rousses e Argentera), ristrutturato durante l’orogenesi Alpina. PhD thesis, Università degli Studi di Milano and Université Claude Bernard Lyon

  39. Di Vincenzo G, Carosi R, Palmeri R (2004) The relationship between tectono-metamorphic evolution and argon isotope records in white mica: constraints from in situ 40Ar–39Ar laser analysis of the Variscan Basement of Sardinia. J Petrol 45:1013–1043

    Article  Google Scholar 

  40. Diener JFA, Powell R, White RW, Holland TJB (2007) A new thermodynamic model for clino- and orthoamphiboles in the system Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O–O. J Metamorph Geol 25:631–656

    Article  Google Scholar 

  41. Domeier M, Torsvik TH (2014) Plate tectonics in the Late Paleozoic. Geosci Front 5:303–350

    Article  Google Scholar 

  42. Donnelly KE, Goldstein SL, Langmuir CH, Spiegelman M (2004) Origin of enriched ocean ridge basalts and implications for mantle dynamics. Earth Plan Sci Lett 226:347–366

    Article  Google Scholar 

  43. Droop GTR (1983) Pre-alpine eclogites in the pennine basement complex of the Eastern Alps. J Metamorph Geol 1(1):3–12

    Article  Google Scholar 

  44. Edel JB, Casini L, Oggiano G, Rossi P, Schulmann K (2014) Early Permian 90° clockwise rotation of the Maures–Estérel–Corsica–Sardinia block confirmed by new palaeomagnetic data and followed by a Triassic 60° clockwise rotation. In: Schulmann K, Martínez Catalán JR, Lardeaux JM, Janoušek V, Oggiano G (eds) The Variscan Orogeny: Extent, Timescale and the Formation of the European Crust. Geological Society London Spl Publ 405, London, pp 333–361

    Google Scholar 

  45. Edel JB, Schulmann K, Lexa O, Lardeaux JM (2018) Late Palaeozoic palaeomagnetic and tectonic constraints for amalgamation of Pangea supercontinent in the European Variscan belt. Earth Sci Rev 177:589–612

    Article  Google Scholar 

  46. Elter FM, Musumeci G, Pertusati PC (1990) Late Hercynian shear zones in Sardinia. Tectonophysics 176:387–404

    Article  Google Scholar 

  47. Ernst WG (1971) Metamorphic zonations on presumably subducted lithospheric plates from Japan, California, and the Alps. Contrib Miner Petrol 34:43–59

    Article  Google Scholar 

  48. Ernst WG, Liou JG (2008) High- and ultrahigh-pressure metamorphism: past results and future prospects. Am Miner 93:1771–1786

    Article  Google Scholar 

  49. Ernst WG, Liu J (1998) Experimental phase-equilibrium study of Al-and Ti-contents of calcic amphibole in MORB—a semiquantitative thermobarometer. Am Miner 83:952–969

    Article  Google Scholar 

  50. Faryad SW, Melcher F, Hoinkes G, Puhl J, Meisel T, Frank W (2002) Relics of eclogite facies metamorphism in the Austroalpine basement, Hochgroessen (Speik complex), Austria. Miner Petrol 74:49–73

    Article  Google Scholar 

  51. Faure M, Bé Mézème E, Duguet M, Cartier C, Talbot JY (2005) Paleozoic tectonic evolution of medio-Europa from the example of the French Massif Central and Massif Armoricain. J Virtual Expl 19(5):1–26

    Google Scholar 

  52. Faure M, Lardeaux JM, Ledru P (2009) A review of the pre-Permian geology of the Variscan French Massif Central. C R Geosci 341:202–213

    Article  Google Scholar 

  53. Faure M, Rossi P, Gaché J, Melleton J, Frei D, Li X, Lin W (2014) Variscan orogeny in Corsica: new structural and geochronological insights, and its place in the Variscan geodynamic framework. Int J Earth Sci 103:1533–1551

    Article  Google Scholar 

  54. Faure-Muret A (1955) Etudes géologiques sur le Massif de l’Argentera–Mercantour et sur ses enveloppes sédimentaires. Mém Carte Géol France, Paris, p 336

    Google Scholar 

  55. Faure-Muret A., Fallot P (1955) Carte géologique de la France au 1/50000. Notice de la feuille de St Etienne de Tinée. XXXVI-40. BRGM

  56. Ferrando S, Lombardo B, Compagnoni R (2008) Metamorphic history of HP mafic granulites from the Gesso-Stura Terrain (Argentera Massif, Western Alps, Italy). Eur J Miner 20:777–790

    Article  Google Scholar 

  57. Ferrara G, Malaroda R (1969) Radiometric age of granitic rocks from the Argentera Massif (Maritime Alps). Boll Soc Geol It 88:311–320

    Google Scholar 

  58. Filippi M, Zanoni D, Gosso G, Lardeaux JM, Verati C, Spalla MI (2019) Structure of lamprophyres: a discriminant marker for Variscan and Alpine tectonics in the Argentera–Mercantour Massif, Maritime Alps. Bull Soc Géol Fr Earth Sciences Bulletin 190:12

    Article  Google Scholar 

  59. Franceschelli M, Puxeddu M, Cruciani G, Utzeri D (2007) Metabasites with eclogite facies relics from Variscides in Sardinia, Italy: a review. Int J Earth Sci 96:795–815

    Article  Google Scholar 

  60. Franke W (1989) Variscan plate tectonics in Central Europe – current ideas and open questions. Tectonophysics 169:221–228

    Article  Google Scholar 

  61. Franke W (2000) The mid-European segment of the Variscides: tectono-stratigraphic units, terrane boundaries and plate tectonic evolution. Geol Soc Sp Pub London 179:35–61

    Article  Google Scholar 

  62. Franke W, Cocks LRM, Torsvik TH (2017) The Palaeozoic Variscan oceans revisited. Gondwana Res 48:257–284

    Article  Google Scholar 

  63. Fréville K, Trap P, Faure M, Melleton J, Li XH, Lin W, Blein O, Bruguiere O, Poujol M (2018) Structural, metamorphic and geochronological insights on the Variscan evolution of the Alpine basement in the Belledonne Massif (France). Tectonophysics 726:14–42

    Article  Google Scholar 

  64. Gasparik T, Lindsley DH (1980) Phase equilibria at high pressure of pyroxenes containing monovalent and trivalent ions. In: Prewitt CT (ed) Pyroxenes: Reviews in mineralogy 7. Mineralogical Society of America, Chantilly, pp 309–339

    Google Scholar 

  65. Gerbault M, Schneider J, Reverso-Peila A, Corsini M (2018) Crustal exhumation during ongoing compression in the Variscan Maures–Tanneron Massif, France-Geological and thermo-mechanical aspects. Tectonophysics 746:439–458

    Article  Google Scholar 

  66. Gerya TV, Perchuk LL, Burg JP (2008) Transient hot channels: perpetrating and regurgitating ultrahigh-pressure, high-temperature crustmantle associations in collision belts. Lithos 103:236–256

    Article  Google Scholar 

  67. Giacomini F, Bomparola RM, Ghezzo C (2005) Petrology and geochronology of metabasites with eclogite facies relics from NE Sardinia: constraints for the Palaeozoic evolution of Southern Europe. Lithos 82:221–248

    Article  Google Scholar 

  68. Giacomini F, Braga R, Tiepolo M, Tribuzio R (2007) New constraints on the origin and age of Variscan eclogitic rocks (Ligurian Alps, Italy). Contrib Miner Petrol 153(1):29–53

    Article  Google Scholar 

  69. Giacomini F, Dallai L, Carminati E, Tiepolo M, Ghezzo C (2008) Exhumation of a Variscan orogenic complex: insights from the composite granulitic–amphibolitic metamorphic basement of South-East Corsica (France). J Metamorph Geol 26:403–436

    Article  Google Scholar 

  70. Gosso G, Lardeaux JM, Zanoni D, Volante S, Corsini M, Bersezio R, Mascle J, Spaggiari L, Spalla MI, Zucali M, Giannerini G, Camera L (2019) Mapping the progressive geologic history at the junction of the Alpine mountain belt and the western Mediterranean ocean. Ofioliti 44:97–110

    Google Scholar 

  71. Graham CM, Powell R (1984) A garnet–hornblende geo-thermometer: calibration testing and application to the Pelona schist, southern California. J Metamorph Geol 2:13–31

    Article  Google Scholar 

  72. Green EC, Holland TJB, Powell R (2007) An order– disorder model for omphacitic pyroxenes in the system jadeite– diopside hedenbergite–acmite, with applications to eclogitic rocks. Am Mimeral 92:1181–1189

    Article  Google Scholar 

  73. Guillot S, Ménot RP (2009) Paleozoic evolution of the external crystalline massifs of the Western Alps. C R Géosci 341:253–265

    Article  Google Scholar 

  74. Guillot S, Di Paola S, Ménot RP, Ledru P, Spalla MI, Gosso G, Schwartz S (2009) Suture zones and importance of strike–slip faulting for Variscan geodynamic reconstructions of the External Crystalline Massifs of the western Alps. Bull Soc géol Fr 6:483–500

    Article  Google Scholar 

  75. Guiraud M, Powell R, Rebay G (2001) H2O in metamorphism and unexpected behaviour in the preservation of metamorphic assemblages. J Metamorph Geol 19:445–454

    Article  Google Scholar 

  76. Hawthorne FC, Oberti R, Harlow GE, Maresch WV, Martin RF, Schumacher JC, Welch MD (2012) Nomenclature of the amphibole supergroup. Amer Minerol 97:2031–2048

    Article  Google Scholar 

  77. Herzberg C, Riccio L, Chiesa A, Fornoni A, Gatto GO, Gregnanin A, Piccirillo EM, Scolari A (1977) Petrogenetic evolution of a spinelgarnet–lherzolite in the austridic crystalline basement from Val Clapa (Alto Adige, northeastern Italy). Memorie degli Istituti di Geologia e Mineralogia dell’Università di Padova, Padova, pp 6–23

    Google Scholar 

  78. Hofmann AW (2003) Sampling mantle heterogeneity through oceanic basalts isotopes and trace elements. In: Carlson RW (ed) The Mantle and Core. Treatise on Geochemistry 2. Elsevier, New York, pp 61–101

    Google Scholar 

  79. Hofmann AW, Jochum KP, Seufert WWM (1986) Nb and Pb in oceanic basalts: new constrains on mantle evolution. Earth Planet Sci Lett 80:299–313

    Article  Google Scholar 

  80. Holland TJB (1990) Activities of components in omphacite solid solutions. Contrib Miner Petrol 105:446–453

    Article  Google Scholar 

  81. Holland TJB, Powell R (1998) An internally consistent thermodynamic dataset for phases of petrological interest. J Metamorph Geol 16:309–343

    Article  Google Scholar 

  82. Holland TJB, Powell R (2003) Activity–composition relations for phases in petrological calculations: an asymmetric multicomponent formulation. Contrib Miner Petrol 145:492–501

    Article  Google Scholar 

  83. Innocent C, Michard A, Guerrot C, Hamelin B (2003) U-Pb zircon age of 548 Ma for the leptynites (high-grade felsic rocks) of the central part of the Maures Massif. Geodynamic significance of the so-called leptyno-amphibolitic complexes of the Variscan belt of western Europe. Bull Soc géol Fr 174:585–594

    Article  Google Scholar 

  84. Irvine TNJ, Baragar WRA (1971) A guide to the chemical classification of the common volcanic rocks. Can J Earth Sci 8:523–548

    Article  Google Scholar 

  85. Joanny V, Lardeaux JM, Trolliard G, Boudeulle M (1989) La transition omphacite =%3e diopside + plagioclase dans les éclogites du Rouergue (Massif central français): un exemple de précipitation discontinue. C R Acad Sci Paris 309:1929–1930

    Google Scholar 

  86. Joanny V, van Roermund H, Lardeaux JM (1991) The clinopyroxene/plagioclase symplectite in retrograde eclogites: a potential geothermometer. Geol Rundsch 80:303–320

    Article  Google Scholar 

  87. Klinkhammer GP, Elderfield H, Edmond JM, Mitra A (1994) Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-ocean ridges. Geochim Cosmochim Acta 58:5105–5113

    Article  Google Scholar 

  88. Konzett J, Krenn K, Hauzenberge C, Whitehouse M, Hoinkes G (2012) High pressure tourmaline formation and fluid activity in FeTi-rich eclogites from the Kreuzeck Mountains, Eastern Alps, Austria. J Petrol 53:99–125

    Article  Google Scholar 

  89. Krogh-Ravna E (2000) The garnet–clinopyroxene Fe2+–Mg geothermometer: an updated calibration. J Metamorph Geol 18:211–219

    Article  Google Scholar 

  90. Labanieh S, Chauvel C, Germa A, Quidelleur X (2012) Martinique: a clear case for sediment melting and slab dehydration as a function of distance to the trench. J Petrol 53:2441–2464

    Article  Google Scholar 

  91. Lardeaux JM (2014a) Deciphering orogeny: a metamorphic perspective. Examples from European Alpine and Variscan belts. Part I: Alpine metamorphism in the western Alps. A review. Bull Soc géol Fr 185:93–114

    Article  Google Scholar 

  92. Lardeaux JM (2014b) Deciphering orogeny: a metamorphic perspective. Examples from European Alpine and Variscan belts. Part II: Variscan metamorphism in the French Massif Central—a review. Bull Soc géol Fr 185:281–310

    Article  Google Scholar 

  93. Lardeaux JM, Ledru P, Daniel I, Duchêne S (2001) The Variscan French Massif Central—a new addition to the ultra-high pressure metamorphic ‘club’: exhumation processes and geodynamic consequences. Tectonophysics 332:143–167

    Article  Google Scholar 

  94. Lardeaux JM, Ménot RP, Orsini JB, Rossi P, Naud G, Libourel G (1994) Corsica and Sardinia in the Variscan chain. In: Keppie JD (ed) Pre-mesozoic geology in France and related areas. Springer, Berlin, pp 467–479

    Google Scholar 

  95. Lardeaux JM, Schulmann K, Faure M, Janoušek V, Lexa O, Skrzypek E, Edel JB, Štípská P (2014) The Moldanubian Zone in the French Massif Central, Vosges/ Schwarzwald and Bohemian Massif revisited: differences and similarities. In: Schulmann K, Martínez Catalán JR, Lardeaux JM, Janoušek V, Oggiano G (eds) The Variscan Orogeny: extent Timescale and the Formation of the European Crust. Geological Society London Spec Publ 405, London, pp 7–44

    Google Scholar 

  96. Latouche L, Bogdanoff S (1987) Evolution précoce du massif de l’Argentera: apport des eclogites et des granulites. Géol Alp 63:151–164

    Google Scholar 

  97. Le Fort P (1973) Geologie du Haut-Dauphine cristallin (Alpes Francaises): Etudes pétrologique et structurale de la partie occidentale. PhD thesis, Université Nancy

  98. Leake BE, Woolley AR, Birch WD, Burke EAJ, Ferraris G, Grice JD, Hawthorne FC, Kisch HJ, Krivovichev VG, Schumacher JC, Stephenson NCN, Whittaker EJW (2004) Nomenclature of amphiboles: additions and revisions to the International Mineralogical Association’s amphibole nomenclature. Eur J Miner 16:191–196

    Article  Google Scholar 

  99. Ledru P, Courrioux G, Dallain C, Lardeaux JM, Montel JM, Vanderhaeghe O, Vitel G (2001) The Velay dome (French Massif Central): melt generation and granite emplacement during orogenic evolution. Tectonophysics 342:207–237

    Article  Google Scholar 

  100. Ledru P, Lardeaux JM, Santallier D, Autran A, Quenardel JM, Floch JP, Lerouge G, Maillet N, Marchand J, Ploquin A (1989) Où sont les nappes dans le Massif central français? Bull Soc géol Fr 8:605–618

    Article  Google Scholar 

  101. Li XH, Faure M, Lin W (2014) From crustal anatexis to mantle melting in the Variscan orogen of Corsica (France): SIMS U-Pb zircon age constraints. Tectonophysics 634:19–30

    Article  Google Scholar 

  102. Liati A, Gebauer D, Fanning M (2009) Geochronological evolution of HP metamorphic rocks of the Adula nappe, Central Alps, in pre-Alpine and Alpine subduction cycles. J Geol Soc 166:797–810

    Article  Google Scholar 

  103. Liégeois JP, Duchesne JC (1981) The Lac Cornu retrograded eclogites (Aiguilles Rouges massif, Western Alps, France): evidence of crustal origin and metasomatic alteration. Lithos 14(1):35–48

    Article  Google Scholar 

  104. Lotout C, Pitra P, Poujol M, Anczkiewicz R, Van Den Driessche J (2018) Timing and duration of variscan high-pressure metamorphism in the French Massif Central: a multimethod geochronological study from the Najac Massif. Lithos 308–309:381–394

    Article  Google Scholar 

  105. Maino M, Dallagiovanna G, Gaggero L, Seno S, Tiepolo M (2012) U-Pb zircon geochronological and petrographic constraints on late to post-collisional Variscan magmatism and metamorphism in the Ligurian Alps. Italy Geol J 47(6):632–652

    Article  Google Scholar 

  106. Malaroda R, Carraro F, Dal Piaz GV, Franceschetti B, Sturani C, Zanella E (1970) Carta geologica del Massiccio dell’Argentera alla scala 1:50.000 e note illustrative. Mem Soc Geol It 9:557–663

    Google Scholar 

  107. Malaroda R, Schiavinato G (1958) Le anatessiti dell'Argentera. Rend Soc Min It 14:249–274

    Google Scholar 

  108. Malaroda R, Schiavinato G (1960) Agmatiti e migmatiti anfiboliche omogenee nel settore meridionale del Massiccio dell’Argentera. Rend Soc Min It 16:335–346

    Google Scholar 

  109. Martínez Catalán JR, Arena R, Abat J, SánchezMartínez S, Díaz García F, Fernández-Suárez J, González Cuadra P, Castiñeiras P, Gómez Barreiro J, Díez Montes A, González Clavijo E, Rubio Pascual FJ, Andonaegui P, Jeffries TE, Alcock JE, Díez Fernández R, López Carmona A (2009) A rootless suture and the loss of the roots of a mountain chain: the Variscan belt of NW Iberia. C R Geosci 341:114–126

    Article  Google Scholar 

  110. Martínez Catalán JR, Arenas R, García FD, Cuadra PG, Gómez-Barreiro J, Abati J, Castiñeiras P, Fernández-Suárez J, Martínez SS, Andonaegui P (2007) Space and time in the tectonic evolution of the northwestern Iberian Massif: implications for the Variscan belt. Geol Soc Am Mem 200:403–423

    Google Scholar 

  111. Matte P (1986) Tectonics and plate tectonics model for the Variscan belt of Europe. Tectonophysics 126:329–374

    Article  Google Scholar 

  112. Matte P (2001) The Variscan collage and orogeny (480–290 Ma) and the tectonic definition of the Armorica microplate: a review. Terra Nova 13:122–128

    Article  Google Scholar 

  113. Matte P, Burg JP (1981) Sutures, thrusts and nappes in the Variscan arc of western Europe. Plate tectonics interpretation. Geol Soc London Sp Pub 8:353–358

    Article  Google Scholar 

  114. Matte P, Maluski H, Rajlich P, Franke W (1990) Terrane boundaries in the Bohemian Massif: result of large-scale Variscan shearing. Tectonophysics 177:151–170

    Article  Google Scholar 

  115. McKenzie D, O’Nions RK (1991) Partial melt distributions from inversion of rare earth element concentrations. J Petrol 32:1021–1091

    Article  Google Scholar 

  116. McKerrow WS, Mac Niocaill C, Ahlberg P, Clayton G, Cleal CJ, Eagar RMC (2000) The Late Palaeozoic relations between Gondwana and Laurussia. Geol Soc Lond Spec Publ 179:9–20

    Article  Google Scholar 

  117. Medaris LG, Jelinek E, Misar Z (1995) Czech eclogites: terrane settings and implications for Variscan tectonic evolution of the Bohemian Massif. Euro J Miner 7:7–28

    Article  Google Scholar 

  118. Melcher F, Meisel T, Puhl J, Koller F (2002) Petrogenesis and geotectonic setting of ultramafic rocks in the Eastern Alps: constraints from geochemistry. Lithos 65(1–2):69–112

    Article  Google Scholar 

  119. Meschede M (1986) A method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the Nb–Zr–Y diagram. Chem Geol 56:207–218

    Article  Google Scholar 

  120. Messiga B, Tribuzio R, Caucia F (1992) Amphibole evolution in Variscan eclogite–amphibolites from the Savona crystalline massif (Western Ligurian Alps, Italy): controls on the decompressional PT–t path. Lithos 27:215–230

    Article  Google Scholar 

  121. Michard A, Albarède F (1986) The REE content of some hydrothermal fluids. Chem Geol 55:51–60

    Article  Google Scholar 

  122. Miyashiro A (1961) Evolution of Metamorphic Belts. J Petrol 2:277–311

    Article  Google Scholar 

  123. Morimoto N (1988) Nomenclature of pyroxenes. Miner Petrol 39:55–76

    Article  Google Scholar 

  124. Morten L, Nimis P, Rampone E (2004) Records of mantle–crust exchange processes during continental subduction–exhumation in the Nonsberg–Ultental garnet peridotites (eastern Alps). A review. Period Mineral 73:119–129

    Google Scholar 

  125. Musumeci G, Colombo F (2002) Late Visean mylonitic granitoids in the Argentera Massif (Western Alps, Italy): age and kinematic constraints on the Ferriere–Mollières shear zone. C R Geosci 334:213–220

    Article  Google Scholar 

  126. Nussbaum C, Marquer D, Biino GG (1998) Two subduction events in a polycyclic basement: Alpine and pre-Alpine high-pressure metamorphism in the Suretta nappe, Swiss Eastern Alps. J Metamorph Geol 16:591–605

    Article  Google Scholar 

  127. Oliot E, Melleton J, Schneider J, Corsini M, Gardien V, Rolland Y (2015) Variscan crustal thickening in the Maures–Tanneron massif (South Variscan belt, France): new in situ monazite U–Th–Pb chemical dating of high-grade rocks. Bull Soc géol Fr 186:145–169

    Article  Google Scholar 

  128. Otten MT (1984) Metamorphism and deformation during and after cooling of the Artfjallet gabbro. J Geol Soc 141:189–190

    Google Scholar 

  129. Palagi P, Laporte D, Lardeaux JM, Menot RP, Orsini JB (1985) Identification d’un complexe leptyno-amphibolique au sein des “gneiss de Belgodère” (Corse occidentale). C R Acad Sci Paris 301:1047–1052

    Google Scholar 

  130. Palmeri R, Fanning M, Franceschelli M, Memmi I, Ricci CA (2004) SHRIMP dating of zircons in eclogite from the Variscan basement in north-eastern Sardinia (Italy). Neu Jahr Min Monat 6:275–288

    Article  Google Scholar 

  131. Paquette JL, Ballèvre M, Peucat JJ, Cornen G (2017) From opening to subduction of an oceanic domain constrained by LA-ICP-MS U-Pb zircon dating (Variscan belt, Southern Armorican Massif, France). Lithos 294:418–437

    Article  Google Scholar 

  132. Pattison DRM (1991) Infiltration-driven anatexis in granulite facies metagabbro, Grenville Province, Ontario, Canada. J Metamorph Geol 9:315–332

    Article  Google Scholar 

  133. Pearce JA (1982) Trace element characteristics of lavas from destructive plate boundaries. Andesites 8:525–548

    Google Scholar 

  134. Pearce JA (1996) A user’s guide to basalt discrimination diagrams. In: Wyman DA (ed) Trace element geochemistry of volcanic rocks: applications for massive sulphide exploration, vol 12. Geological Association of Canada, Short Course Notes, Newfoundland, pp 79–113

    Google Scholar 

  135. Pearce JA (2008) Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos 100:14–48

    Article  Google Scholar 

  136. Polino R, Dal Piaz GV, Gosso G (1990) Tectonic erosion at the Adria margin and accretionary processes for the Cretaceous orogeny of the Alps. Mem Soc géol Fr 156:345–367

    Google Scholar 

  137. Rebay G, Powell R, Diener J (2010) Calculated phase equilibria for a MORB composition in a P T window, 450–650 °C and 18–28 kbar: the stability of eclogite. J Metamorph Geol 28:635–645

    Article  Google Scholar 

  138. Regorda A, Lardeaux JM, Roda M, Marotta AM, Spalla MI (2019) How many subductions in the Variscan orogeny? Insights from numerical models. Geosci Front. https://doi.org/10.1016/j.gsf.2019.10.005

    Article  Google Scholar 

  139. Roda M, Regorda A, Spalla MI, Marotta AM (2019) What drives Alpine Tethys opening? Clues from the review of geological data and model predictions. Geol J 54:2646–2664

    Article  Google Scholar 

  140. Rossi P, Oggiano G, Cocherie A (2009) A restored section of the ‘‘southern Variscan realm’’ across the Corsica–Sardinia microcontinent. C R Geosci 341:224–238

    Article  Google Scholar 

  141. Rubatto D, Ferrando S, Compagnoni R, Lombardo B (2010) Carboniferous high-pressure metamorphism of Ordovician protoliths in the Argentera Massif (Italy), Southern European Variscan belt. Lithos 116:65–76

    Article  Google Scholar 

  142. Rubatto D, Schaltegger U, Lombardo B, Colombo F, Compagnoni R (2001) Complex Paleozoic magmatic and metamorphic evolution in the Argentera Massif (Western Alps), resolved with U–Pb dating. Schweiz Miner Petrogr Mitt 81:213–228

    Google Scholar 

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

    Article  Google Scholar 

  144. Saccani E (2015) A new method of discriminating different types of post-Archean ophiolitic basalts and their tectonic significance using Th–Nb and Ce–Dy–Yb systematics. Geosc Front 6:481–501

    Article  Google Scholar 

  145. Sanchez G, Rolland Y, Schneider J, Corsini M, Oliot E, Goncalves P, Verati C, Lardeaux JM, Marquer D (2011) Dating low-temperature deformation by 40Ar/39Ar on white mica, insights from the Argentera–Mercantour Massif (SW Alps). Lithos 125:521–536

    Article  Google Scholar 

  146. Sanchez G, Rolland Y, Schreiber D, Giannerini G, Corsini M, Lardeaux JM (2010) The active fault system of SW Alps. J Geodyn 49(5):296–302

    Article  Google Scholar 

  147. Schmid SM, Fügenschuh B, Kissling E, Schuster R (2004) Tectonic map and overall architecture of the Alpine orogen. Eclog Geol Helv 97:93–117

    Article  Google Scholar 

  148. Schmidt MW, Poli S (1998) Experimentally based water budgets for dehydrating slabs and consequences for arc magma generation. Earth Planet Sci Lett 163:361–379

    Article  Google Scholar 

  149. Schneider J, Corsini M, Reverso-Peila A, Lardeaux JM (2014) Thermal and mechanical evolution of an orogenic wedge during Variscan collision: an example in the Maures-Tanneron Massif (SE France). In: Schulmann K, Martínez Catalán JR, Lardeaux JM, Janoušek V, Oggiano G (eds) The Variscan Orogeny: extent, timescale and the formation of the European Crust, vol Spec Publ 405. Geol Soc London, London, pp 313–331

    Google Scholar 

  150. Schreiber D, Lardeaux JM, Martelet G, Courrioux G, Guillen A (2010) 3-D modelling of Alpine Mohos in Southwestern Alps. Geophys J Int 180:961–975

    Article  Google Scholar 

  151. Schulmann K, Konopásek J, Janoušek V, Lexa O, Lardeaux JM, Edel JB, Stípská P, Ulrich S (2009) An Andean type Palaeozoic convergence in the Bohemian Massif. C R Geosci 341:266–286

    Article  Google Scholar 

  152. Schulmann K, Kröner A, Hegner E, Wend I, Konopasek J, Lexa O, Stipská P (2005) Chronological constraints on the pre-orogenic history, burial and exhumation of deep-seated rocks along the eastern margin of the Variscan Orogen, Bohemian Massif, Czech Republic. Am J Sci 305:407–448

    Article  Google Scholar 

  153. Schulmann K, Lexa O, Janoušek V, Lardeaux JM, Edel JB (2014) Anatomy of a diffuse cryptic suture zone: an example from the Bohemian Massif, European Variscides. Geology 42:275–278

    Article  Google Scholar 

  154. Schultz B, Bombach K, Pawlig S, Brätz H (2004) Neoproterozoic to Early-Palaeozoic magmatic evolution in the Gondwana-derived Austroalpine basement to the south of the Tauern Window (Eastern Alps). Int J Earth Sci 93:824–843

    Article  Google Scholar 

  155. Schwartz S, Lardeaux JM, Tricart P, Guillot S, Labrin E (2007) Diachronous exhumation of HP–LT metamorphic rocks from south-western Alps: evidence from fission track analysis. Terra Nova 19:133–140

    Article  Google Scholar 

  156. Schweinehage R, Massonne H (1999) Geochemistry and metamorphic evolution of metabasites from the Silvretta nappe Eastern Alps. Mem Sci Geol 51(1):191–203

    Google Scholar 

  157. Shervais JW (1982) TiV plots and the petrogenesis of modern and ophiolitic lavas. Earth Planet Sci Lett 59:101–118

    Article  Google Scholar 

  158. Simonetti M, Carosi R, Montomoli C, Langone A, D’Addario E, Mammoliti E (2018) Kinematic and geochronological constraints on shear deformation in the Ferriere–Mollières shear zone (Argentera–Mercantour Massif, Western Alps): implications for the evolution of the Southern European Variscan Belt. Int J Earth Sci 107:2163–2189

    Article  Google Scholar 

  159. Spalla MI, Marotta AM (2007) PT evolutions vs. numerical modelling: a key to unravel the Paleozoic to early-Mesozoic tectonic evolution of the Alpine area. Per Miner 76:267–308

    Google Scholar 

  160. Spalla MI, Zanoni D, Marotta AM, Rebay G, Roda M, Zucali M, Gosso G (2014) The transition from Variscan collision to continental break-up in the Alps: insights from the comparison between natural data and numerical model predictions. In: Schulmann K, Martínez Catalán JR, Lardeaux JM, Janoušek V, Oggiano G (eds) The Variscan orogeny: extent, timescale and the formation of the European Crust, vol Spec Pub 405. Geol Soc London, London, pp 363–400

    Google Scholar 

  161. Spear FS (1993) Metamorphic phase equilibria and pressure–temperature–time paths. Min Soc Am Monogr Ser 1:789

    Google Scholar 

  162. Spiess R, Cesare B, Mazzoli C, Sassi R, Sassi FP (2010) The crystalline basement of the Adria microplate in the eastern Alps: a review of the palaeo-structural evolution from the Neoproterozoic to the Cenozoic. Rend Lincei Sci Fis Nat 21:31–50

    Article  Google Scholar 

  163. Stampfli GM, Hochard C, Vérard C, Wilhem C, VonRaumer J (2013) The formation of Pangea. Tectonophysics 593:1–19

    Article  Google Scholar 

  164. Sun SS, 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, vol 42. Geol Soc London Spec Publ, London, pp 313–345

    Google Scholar 

  165. Tait JA, Bachtadse V, Franke W, Soffel HC (1997) Geodynamic evolution of the European Variscan fold belt: palaeomagnetic and geological constraints. Geol Rundsch 86:585–598

    Article  Google Scholar 

  166. Thompson R, Morrison MA, Dickin A, Hendry GL (1983) Continental flood basalts arachnids rule OK? In: Hawkesworth CJ, Norry MJ (eds) Continental Basalts and Mantle Xenoliths. Shiva Publications, India, pp 158–185

    Google Scholar 

  167. Tomkins HS, Powell R, Ellis DJ (2007) The pressure dependence of the zirconium-in-rutile thermometer. J Metamorph Geol 25:703–713

    Article  Google Scholar 

  168. Torsvik TH, Smethurst MA, Briden JC, Sturt BA (1990) A review of Paleozoic paleomagnetic data from Europe and their paleogeographic implications. Palaeozoic palaeogeography and biogeography 12. Geological Soc Publishing House, Bath, pp 25–41

    Google Scholar 

  169. Torsvik TH, Smethurst M, Meert JG, Van der Voo R, McKerrow W, Brasier M, Sturt B, Walderhaug H (1996) Continental break-up and collision in the Neoproterozoic and Palaeozoica tale of Baltica and Laurentia. Earth Sci Rev 40:229–258

    Article  Google Scholar 

  170. Tumiati S, Thöni M, Nimis P, Martin S, Mair V (2003) Mantle–crust interactions during Variscan subduction in the Eastern Alps (Nonsberg–Ulten zone): Geochronology and new petrological constraints. Earth Planet Sci Lett 210(3–4):509–526

    Article  Google Scholar 

  171. Von Raumer JF (1984) The External Massifs, relics of Variscan basement in the Alps. Geol Rundsch 73:1–31

    Article  Google Scholar 

  172. Von Raumer JF, Abrecht J, Bussy F, Lombardo B, Ménot RP, Schaltegger U (1999) The Palaeozoic metamorphic evolution of the Alpine External Massifs. Schweiz Miner Petrogr Mitt 79:5–22

    Google Scholar 

  173. Von Raumer JF, Bussy F, Schaltegger U, Schulz B, Stampfli GM (2013) Pre Mesozoic–Alpine basements—their place in the European Paleozoic framework. GSA Bull 125:89–108

    Article  Google Scholar 

  174. Von Raumer JF, Bussy F, Stampfli GM (2009) The Variscan evolution in the External massifs of the Alps and place in their Variscan framework. C R Geosci 341:239–252

    Article  Google Scholar 

  175. Von Raumer JF, Stampfli GM, Borel G, Bussy F (2002) Organization of pre-Variscan basement areas at the north- Gondwana margin. Int J Earth Sci 91:35–52

    Article  Google Scholar 

  176. Von Raumer JF, Stampfli GM, Bussy F (2003) Gondwana-derived microcontinents—the constituents of the Variscan and Alpine collisional orogens. Tectnophysics 365:7–22

    Article  Google Scholar 

  177. Watson EB, Wark DA, Thomas JB (2006) Crystallization thermometers for zircon and rutile. Contrib Miner Petrol 151:413–433

    Article  Google Scholar 

  178. White RW, Powell R, Clarke GL (2002) The interpretation of reaction textures in Fe-rich metapelitic granulites of the Musgrave Block, central Australia: constraints from mineral equilibria calculations in the system K2O–FeO–MgO– Al2O3–SiO2–H2O–TiO2–Fe2O3. J Metamorph Geol 20:41–55

    Article  Google Scholar 

  179. White RW, Powell R, Holland TJB (2007) Progress relating to calculation of partial melting equilibria for metapelites. J Metamorph Geol 25:511–527

    Article  Google Scholar 

  180. White RW, Powell R, Holland TJB, Worley BA (2000) The effect of TiO2 and Fe2O3 on metapelitic assemblages at greenschist and amphibolite facies conditions: mineral equilibria calculations in the system: K2OFeOMgOAl2O3SiO2H2OTiO2Fe2O3. J Metamorph Geol 18:497–511

    Article  Google Scholar 

  181. Winchester JA, Floyd PA (1977) Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chem Geol 20:325–343

    Article  Google Scholar 

  182. Zimmermann VR, Franz G (1989) Die Eklogite der Unteren Schieferhülle; Frosnitztal/Südvenediger (Tauern, Österreich). Mittelungen Östereichischen Geologischen Gesellschaft 81:167–188

    Google Scholar 

  183. Štípská P, Powell R (2005) Constraining the P–T path of a MORB-type eclogite using pseudosections, garnet zoning and garnet–clinopyroxene thermometry: an example from the Bohemian Massif. J Metamorph Geol 23:725–743

    Article  Google Scholar 

  184. Štípská P, Powell R, Racek M, Lexa O (2014) Intermediate granulite produced by transformation of eclogite at a felsic granulite contact, in Blansky les, Bohemian Massif. J Metamorph Geol 32:347–370

    Article  Google Scholar 

  185. Štípská P, Schulmann K, Kröner A (2004) Vertical extrusion and middle crustal spreading of omphacite granulite: a model of syn-convergent exhumation (Bohemian Massif, Czech Republic). J Metamorph Geol 22:179–198

    Article  Google Scholar 

Download references

Acknowledgements

We thank Stephen Collett and an anonymous reviewer for their generous, thoughtful and detailed comments on an early version of this manuscript. Italian authors acknowledge funding by PSR2019-IBOLLATI (University of Milano). We thank Pavla Štípská for her editorial work.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Fabrice Jouffray.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary file1 (PDF 3039 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Jouffray, F., Spalla, M.I., Lardeaux, J.M. et al. Variscan eclogites from the Argentera–Mercantour Massif (External Crystalline Massifs, SW Alps): a dismembered cryptic suture zone. Int J Earth Sci (Geol Rundsch) 109, 1273–1294 (2020). https://doi.org/10.1007/s00531-020-01848-2

Download citation

Keywords

  • Argentera–Mercantour
  • Southwestern alps
  • Variscan eclogites
  • Protoliths geochemistry
  • Metamorphic evolution
  • 40Ar/39Ar dating