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Source tracing of detrital serpentinite in the Oligocene molasse deposits from the western Alps (Barrême basin): implications for relief formation in the internal zone

Published online by Cambridge University Press:  31 January 2012

S. SCHWARTZ*
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
S. GUILLOT
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
P. TRICART
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
M. BERNET
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
S. JOURDAN
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
T. DUMONT
Affiliation:
IsTerre, CNRS, Université Joseph Fourier (Grenoble1), F-38041 Grenoble, Cedex 9, France
G. MONTAGNAC
Affiliation:
Laboratoire des Sciences de la Terre, CNRS, ENS Lyon, France
*
Author for correspondence: stephane.schwartz@ujf-grenoble.fr

Abstract

We present the first contribution of tracing the source area of ophiolitic detritus in the Alpine molasse deposits by Raman spectroscopy. The lower Oligocene molasse deposits preserved in the Barrême basin, in the SW foreland of the western Alpine arc, are known for the sudden arrival of the first ‘exotic’ detritus coming from the internal Alpine zones. Among them, the pebbles of serpentinized peridotites have so far not been studied. We show that they only consist of antigorite serpentinite, implying that they originate from erosion of high temperature blueschists. In contrast, the upper Oligocene/lower Miocene molasse shows mixed clasts of serpentine including antigorite and lizardite without any evidence of chrysotile. This suggests that they were derived from a less metamorphosed unit such as the low temperature blueschist unit. Taking into account the sediment transport direction in the basin and the varied metamorphic characteristics of the other ocean-derived detritus, we constrain the lithologic nature of the source zones and the location of the relief zones, identified as the internal Alps, SE of the Pelvoux external crystalline massif. Available structural data and in situ thermochronological data allow the reconstruction of the Oligocene to early Miocene collisional geometry of the Palaeogene subduction wedge. This phase corresponds to two major phases of uplift evolving from a single relief zone located above the Ivrea body during early Oligocene times and persisting up to early Miocene times; then during late Oligocene/early Miocene times a second relief zone developed above the Briançonnais zone. At that time, the internal western Alps acquired its double vergency.

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Original Articles
Copyright
Copyright © Cambridge University Press 2012

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References

Agard, P., Monié, P., Jolivet, L. & Goffé, B. 2002. Exhumation of the Schistes Lustres complex: in situ laser probe Ar-40/Ar-39 constraints and implications for the Western Alps. Journal of Metamorphic Geology 20, 599618.CrossRefGoogle Scholar
Agard, P., Vidal, O. & Goffé, B. 2001. Interlayer and Si content of phengite in HP-LT carpholite-bearing metapelites. Journal of Metamorphic Geology 19, 477–93.CrossRefGoogle Scholar
Andréani, M., Mével, C., Boullier, A. M. & Escartin, J. 2007. Dynamic control on serpentine crystallisation in veins: constraints on hydration processes in oceanic peridotites. Geochemistry, Geophysics, Geosystems Q02012, doi: 10.1029/2006GC001373.Google Scholar
Artoni, A. & Meckel, L. D. III. 1998. History and deformation rates of a thrust sheet top basin: the Barrême basin, western Alps, SE France. In Cenozoic Foreland Basins of Western Europe (eds Mascle, A., Puigdefàbregas, C., Luterbacher, H. P. & Fernàndez, M.), pp. 213–37. Geological Society of London, Special Publication no. 134.Google Scholar
Auzende, A. L., Daniel, I., Reynard, B., Lemaire, C. & Guyot, F. 2004. High-pressure behaviour of serpentine minerals: a Raman spectroscopic study. Physics and Chemistry of Minerals 31, 269–77.CrossRefGoogle Scholar
Auzende, A. L., Devouard, B., Guillot, S., Daniel, I., Baronnet, A. & Lardeaux, J. M. 2002. Serpentinites from Central Cuba: petrology and HRTEM study. European Journal of Mineralogy 14, 905–14.CrossRefGoogle Scholar
Auzende, A. L., Guillot, S., Devouard, B. & Baronnet, A. 2006. Serpentinites in an Alpine convergent setting: effects of metamorphic grade and deformation on microstructures. European Journal of Mineralogy 18, 2133.CrossRefGoogle Scholar
Barnicoat, A. C. 1985. High-pressure metamorphism in the Zermatt-Saas zone of the Swiss Alps. Journal of the Geological Society, London 142, 1243–43.Google Scholar
Bernet, M., Brandon, M., Garver, J., Balestieri, M. L., Ventura, B. & Zattin, M. 2009. Exhuming the Alps through time: clues from detrital zircon fission-track thermochronology. Basin Research 21, 781–98.CrossRefGoogle Scholar
Bernet, M. & Garver, J. I. 2005. Fission-track analysis of detrital zircon. In Low-Temperature Thermochronology (eds Reiners, P. & Ehlers, T.), pp. 205–38. Reviews in Mineralogy & Geochemistry no. 58.CrossRefGoogle Scholar
Bernet, M. & Spiegel, C. 2004. Introduction: Detrital thermochronology. In Detrital Thermochronology: Provenance analysis, Exhumation and Landscape Evolution of Mountain Belts (eds Bernet, M. & Spiegel, C.), pp. 18. Geological Society of America, Special Publication no. 378.CrossRefGoogle Scholar
Bernet, M. & Tricart, P. 2011. The Oligocene orogenic pulse in the Southern Penninic Arc (Western Alps): structural, sedimentary and thermochronological constraints. Bulletin de la Société géologique de France 182, 2536.CrossRefGoogle Scholar
Blake, M. C. & Jayko, A. S. 1990. Uplift of very high pressure rocks in the western Alps: evidence for structural attenuation along low angle faults. In Deep Structure of the Alps (eds Roure, F., Heitzmann, P. & Polino, R.), pp. 228–37. Mémoire de la Société Géologique de France 156.Google Scholar
Bodelle, J. 1971. Les formations nummulitiques de l'Arc de Castellane. Published Ph.D. thesis, Université de Nice. Documents du BRGM 2, 585 pp.Google Scholar
Bousquet, R., Oberhänsli, R., Goffé, B., Wiederkehr, M., Koller, F., Schmid, S. M., Schuster, R., Engi, M., Berger, A. & Martinotti, G. 2008. Metamorphism of metasediments at the scale of an orogen: a key to the Tertiary geodynamic evolution of the Alps. In Tectonic Aspects of the Alpine-Dinaride-Carpathian System (eds Siegesmund, S., Fügenschuh, B. & Froitzheim, N.), pp. 393411. Geological Society of London, Special Publication no. 298.Google Scholar
Burbank, D. W. 2002. Rates of erosion and their implications for exhumation. Mineralogical Magazine 66, 2552.CrossRefGoogle Scholar
Callec, Y. 2001. La déformation synsédimentaire des bassins paléogènes de l'arc de Castellane. Mémoire des Sciences de la Terre de l'Ecole des Mines de Paris 43, 1347.Google Scholar
Carrapa, B., Wijbrans, J. & Bertotti, G. 2003. Episodic exhumation in the Western Alps. Geology 31, 601–4.2.0.CO;2>CrossRefGoogle Scholar
Carter, A. & Bristow, C. S. 2000. Detrital zircon geochronology: enhancing the quality of sedimentary source information through improved methodology and combined U–Pb and fission-track techniques. Basin Research 12, 4757.CrossRefGoogle Scholar
Chalot-Prat, F. 2005. An underformed ophiolite in the Alps: Field and geochemical evidence for a link between volcanism and shallow plate tectonic processes. In Plates, Plumes, and Paradigms (eds Foulger, G. R., Natland, J. H., Presnall, D. C. & Anderson, D. L.), pp. 751–80. Geological Society of America, Special Paper no. 388.Google Scholar
Chauveau, J. C. & Lemoine, M. 1961. Contribution à l'étude géologique du synclinal tertiaire de Barrême (moitié nord). Bulletin de la Carte géologique de France 264, 147–78.Google Scholar
Chopin, C., Henry, C. & Michard, A. 1991. Geology and petrology of the coesite bearing terrain, Dora-Maira massif, western Alps. European Journal of Mineralogy 3, 263–91.CrossRefGoogle Scholar
Choukroune, P., Ballèvre, M., Cobbold, P., Gautier, Y., Merle, O. & Vuichard, J. P. 1986. Deformation and motion in the Western Alpine Arc. Tectonics 5, 215–26.CrossRefGoogle Scholar
Claudel, M. E. & Dumont, T. 1999. Early and Late Jurassic rifting events in the French Briançonnais relative to the evolution of the Ligurian Tethys and Valais oceans. Eclogae Geologicae Helvetiae 92, 4561.Google Scholar
Collombet, M., Thomas, J. C., Chauvin, Y., Tricart, P., Bouillin, J. P. & Gratier, J. P. 2002. Counterclockwise rotation of the western Alps since the Oligocene: new insights from paleomagnetic data. Tectonics 21, 1115.CrossRefGoogle Scholar
Compagnoni, R. & Rolfo, F. 2003. UHPM units in the western Alps. European Mineralogy Union Notes in Mineralogy 5, 1349.Google Scholar
Cordey, F., Tricart, P., Guillot, S. & Schwartz, S. In press. Dating the Tethyan ocean in the Western Alps with radiolarite pebbles from Oligocene foreland molasse (southeast France). Swiss Journal of Geosciences.Google Scholar
Coward, M. P. & Dietrich, D. 1989. Alpine Tectonics: an overview. In Alpine Tectonics (Coward, M. P., Dietrich, D. & Parks, R. G.), pp. 129. Geological Society of London, Special Publication no. 45.Google Scholar
Deville, E., Fudral, S., Lagabrielle, Y., Marthaler, M. & Sartori, M. 1992. From oceanic closure to continental collision: a synthesis of the Schistes lustrés metamorphic complex of the western Alps. Geological Society of America Bulletin 104, 127–39.2.3.CO;2>CrossRefGoogle Scholar
Dickinson, W. R. & Suczek, C. A. 1979. Plate tectonics and sandstone composition. American Association of Petroleum Geologists Bulletin 63, 2164–82.Google Scholar
Duchêne, S., Blichert-Toft, J., Luais, B., Télouk, P., Lardeaux, J. M. & Albarède, F. 1997. The Lu-Hf dating of garnets and the ages of the Alpine high-pressure metamorphism. Nature 387, 586–9.Google Scholar
Dumont, T., Champagnac, J.-D., Crouzet, C. & Rochat, P. 2008. Multistage shortening in the Dauphiné zone (French Alps): the record of Alpine collision and implications for pre-Alpine restoration. Swiss Journal of Geosciences 101, 89110.CrossRefGoogle Scholar
Evans, B. W. 2004. The serpentinite multisystem revisited: chrysotile is metastable. International Geology Review 46, 479506.CrossRefGoogle Scholar
Evans, M. J. & Elliott, T. 1999. Evolution of a thrust-sheet-top basin: the Tertiary Barrême basin, Alpes de Haute Provence, France. Geological Society of America Bulletin 111, 1617–43.2.3.CO;2>CrossRefGoogle Scholar
Evans, M. J. & Mange-Rajetzky, M. A. 1991. The provenance of sediments in the Barrême thrust-top basin, Haute-Provence, France. In Developments in Sedimentary Provenance Studies (eds Morton, A. C., Todd, S. P. & Haughton, P. D. W.), pp. 323–42. Geological Society of London, Special Publication no. 57.Google Scholar
Federico, L., Capponi, G., Crispini, L. & Scambelluri, M. 2004. Exhumation of alpine high-pressure rocks: insights from petrology of eclogite clasts in the Tertiary Piedmontese basin (Ligurian Alps, Italy). Lithos 74, 2140 CrossRefGoogle Scholar
Ford, M., Duchene, S., Gasquet, D. & Vanderhaeghe, O. 2006. Two-phase orogenic convergence in the external and internal SW Alps. Journal of the Geological Society, London 163, 815–26.CrossRefGoogle Scholar
Ford, M. & Lickorish, W. H. 2004. Foreland basin evolution around the western Alpine arc. In Deep-water Sedimentation in the Alpine basin of SE France: New perspectives on the Grès d'Annot (eds Joseph, P. & Lomas, S. A.), pp. 3963. Geological Society of London, Special Publication no. 221.Google Scholar
Ford, M., Lickorish, W. H. & Kusznir, N. J. 1999. Tertiary foreland sedimentation in the Southern Subalpine Chains, SE France: a geodynamic appraisal. Basin Research 11, 315–36.CrossRefGoogle Scholar
Garzanti, E., Ando, S. & Scutella, N. 2000. Actualistic ophiolite provenance: the Cyprus case. Journal of Geology 108, 199218.CrossRefGoogle ScholarPubMed
Garzanti, E. & Malusà, M. 2008. The Oligocene Alps: domal unroofing and drainage development during early orogenic growth. Earth and Planetary Science Letters 268, 487500.CrossRefGoogle Scholar
Garzanti, E., Vezzoli, G., Ando, S., Lave, J., Attal, M., France-Lanord, C. & Decelles, P. 2007. Quantifying sand provenance and erosion (Marsyandi River, Nepal Himalaya). Earth and Planetary Science Letters 258, 500–15.CrossRefGoogle Scholar
Goffé, B., Schwartz, S., Lardeaux, J.-M. & Bousquet, R. 2004. Exploratory notes to the map: metamorphic structure of the Alps, Western and Ligurian Alps. Mitteilungen der Osterereichischen Mineralogischen Gesellschaft 149, 125–44.Google Scholar
de Graciansky, P. C. 1972. Le bassin tertiaire de Barrême (Alpes de Haute-Provence): relations entre déformation et sédimentation; chronologie des plissementss. Comptes Rendus de l'Académie des Sciences, Paris (D) 275, 2825–8.Google Scholar
de Graciansky, P. C. 1982. Notice Explicative de la Feuille Digne à 1/50 000. Orléans: BRGM (Bureau des Recherches Géologiques et Miniéres).Google Scholar
de Graciansky, P. C., Lemoine, M. & Saliot, P. 1971. Remarques sur la présence de minéraux et de paragenèses du métamorphisme alpin dans les galets des conglomérats oligocènes du synclinal de Barrême (Alpes de Haute-Provence). Comptes Rendus de l'Académie des Sciences, Paris (D) 272, 3243–45.Google Scholar
Gratier, J. P., Ménard, G. & Arpin, R. 1989. Strain-displacement compatibility and restoration of the Chaînes Subalpine of the western Alps. In Alpine Tectonics (Coward, M. P., Dietrich, D. & Parks, R. G.), pp. 6581. Geological Society of London, Special Publication no. 45.Google Scholar
Groppo, C. & Compagnoni, R. 2007. Metamorphic veins from the serpentinites of the Piemonte Zone, western Alps, Italy: a review. Periodico di Mineralogia 76, 127–53.Google Scholar
Groppo, C., Rinaudo, C., Cairo, S., Gastaldi, D. & Compagnoni, R. 2006. Micro-Raman spectroscopy for quick and reliable identification of serpentinite minerals from ultramafics. European Journal of Mineralogy 18, 319–29.CrossRefGoogle Scholar
Guillot, S., Hattori, K., Agard, P., Schwartz, S. & Vidal, O. 2009. Exhumation processes in oceanic and continental subduction contexts: a review. In Subduction Zone Dynamics (eds Lallemand, S. & Funiciello, F.), pp. 175204. Berlin, Heidelberg: Springer-Verlag.CrossRefGoogle Scholar
Guillot, S., Hattori, K. H. & De Sigoyer, J. 2000. Mantle wedge serpentinization and exhumation of eclogites: insights from eastern Ladakh, northwest Himalaya. Geology 28, 199202.2.0.CO;2>CrossRefGoogle Scholar
Joseph, P. & Lomas, S. A. 2004. Deep-water sedimentation in the Alpine Foreland Basin of SE France: new perspectives on the Grès d'Annot and related systems – an introduction. In Deep-water Sedimentation in the Alpine basin of SE France: New perspectives on the Gres D'Annot and related systems (eds Joseph, P. & Lomas, S. A.), pp. 116. Geological Society of London, Special Publication no. 221.Google Scholar
Jourdan, S., Bernet, M., Tricart, P., Guillot, S., Schwartz, S. & Dumont, T. 2011. New constraints on the Western Alpine wedge 30–20 My ago from multi-method provenance analysis of foreland basin deposits. Geophysical Research Abstracts 13, EGU20119367.Google Scholar
Kerckhove, C. 1969. La “zone du Flysch” dans les nappes d'Embrunais-Ubaye. Géologie Alpine 45, 5204.Google Scholar
Lardeaux, J. M., Schwartz, S., Tricart, P., Paul, A., Guillot, S., Bethoux, N. & Masson, F. 2006. A crustal-scale cross-section of the south-western Alps combining geophysical and geological imagery. Terra Nova 18, 412–22.CrossRefGoogle Scholar
Lombardo, B., Nervo, R., Compagnoni, R., Messiga, B., Kienast, J. R., Mével, C., Fiora, L., Piccardo, G. B. & Lanza, R. 1978. Osservazioni preliminari sulle ofiolite metamorfiche del Monviso (Alpi Occidentali). Rendi Conti Società Italiana di Mineralogia e Petrologia 34, 253305.Google Scholar
Malusà, M., Polino, R. & Martin, S. 2005. The Gran San Bernardo nappe in the Aosta valley (western Alps): a composite stack of distinct continental crust units. Bulletin de la Société Géologique de France 176, 417–31.CrossRefGoogle Scholar
Malusà, M., Polino, R. & Zattin, M. 2009. Strain partitioning in the axial NW Alps since the Oligocene. Tectonics 28, 126.CrossRefGoogle Scholar
Malusà, M., Polino, R., Zattin, M., Bigazzi, G., Martin, S. & Piana, F. 2005. Miocene to Present differential exhumation in the Western Alps: insights from fission track thermochronology. Tectonics 24, TC2005, doi:10.1029/2004TC001782.CrossRefGoogle Scholar
McBride, E. F. & Picard, M. D. 1987. Downstream changes in sand compaction and roundness in a short-headed, high-gradient stream, Liguria, Italy. Journal of Sedimentary Petrology 57, 1018–26.Google Scholar
Morag, N., Avigad, D., Harlavan, Y., McWilliams, O. & Michard, A. 2008. Rapid exhumation and mountain building in the Western Alps: petrology and 40Ar/39Ar geochronology of detritus from Tertiary basins of southeastern France. Tectonics 27, TC2004, doi:10.1029/2007TC002142.CrossRefGoogle Scholar
Najman, Y. & Garzanti, E. 2000. An integrated approach to provenance studies: reconstructing early Himalayan palaeogeography and tectonic evolution from Tertiary foredeep sediments, N. India. Geological Society of America Bulletin 112, 435–49.2.0.CO;2>CrossRefGoogle Scholar
Philippot, P. 1990. Opposite vergence of nappes and crustal extension in the French-Italian Western Alps. Tectonics 9, 1143–64.CrossRefGoogle Scholar
Platt, J. P. 1986. Dynamic of orogenic wedges and the uplift of high-pressure metamorphic rocks. Geological Society of America Bulletin 97, 1037–53.2.0.CO;2>CrossRefGoogle Scholar
Platt, J. P. 1987. The uplift of high-pressure low temperature metamorphic rocks. Philosophical Transactions of the Royal Society of London A321, 87103.Google Scholar
Platt, J. P. 1993. Exhumation of high-pressure rocks – a review of concepts and processes. Terra Nova 5, 119–33.CrossRefGoogle Scholar
Platt, J. P., Behrmann, J. H., Cunningham, P. C., Dewey, J. F., Helman, M., Parish, M., Shepley, M. G., Wallis, S. & Weston, P. G. 1989. Kinematics of the Alpine arc and the motion history of Adria. Nature 337, 158–61.CrossRefGoogle Scholar
Polino, R., Ruffini, R. & Ricci, B. 1991. Le molasse terziarie della collina di Torino: relazioni con la cinematica alpina. Atti Ticinensi Scienze della Terra 34, 8595.Google Scholar
Rinaudo, C., Gastaldi, D. & Belluso, E. 2003. Characterization of chrysotile, antigorite, and lizardite by FT-Raman spectroscopy. Canadian Journal of Mineralogy 41, 883–90.CrossRefGoogle Scholar
Rolland, Y., Lardeaux, J. M., Guillot, S. & Nicollet, C. 2000. Syn-convergence extension, vertical pinching and contrasted metamorphic units on the western edge of the Gran Paradise massif (French-Italian Alps). Geodinamica Acta 13, 133–48.Google Scholar
Rosenbaum, G. & Lister, G. S. 2005. The western Alps from the Jurassic to Oligocene: spatio-temporal constraints and evolutionary reconstructions. Earth Science Reviews 69, 281306.CrossRefGoogle Scholar
Rubatto, D. & Hermann, J. 2001. Exhumation as fast as subduction? Geology 29, 36.2.0.CO;2>CrossRefGoogle Scholar
Scambelluri, M., Muntener, O., Hermann, J., Piccardo, G. B. & Trommsdorff, V. 1995. Subduction of water into the mantle – history of an alpine peridotite. Geology 23, 459–62.2.3.CO;2>CrossRefGoogle Scholar
Schmid, S. M. & Kissling, E. 2000. The arc of the western Alps in the light of geophysical data on deep crustal structure. Tectonics 19, 6285.CrossRefGoogle Scholar
Schwartz, S., Allemand, P. & Guillot, S. 2001. Numerical model of the effect of serpentinites on the exhumation of eclogitic rocks: insights from the Monviso ophiolitic massif (Western Alps). Tectonophysics 342, 193206.CrossRefGoogle Scholar
Schwartz, S., Lardeaux, J. M., Guillot, S. & Tricart, P. 2000. Diversité du métamorphisme écologitique dans le massif ophiolitique du Monviso (Alpes occidentales, Italie). Geodynamica Acta 13, 169–88.Google Scholar
Schwartz, S., Lardeaux, J. M., 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, 133–40.CrossRefGoogle Scholar
Schwartz, S., Tricart, P., Lardeaux, J. M., Guillot, S. & Vidal, O. 2009. Late tectonic and metamorphic evolution of the Piedmont accretionary wedge (Queyras Schistes lustrés, western Alps): evidences for tilting during Alpine collision. Geological Society of America Bulletin 121, 502–18.CrossRefGoogle Scholar
Sérrane, M. 1999. The Gulf of Lion continental margin (NW Mediterranean) revisited by IBS: an overview. In The Mediterranean Basins: Tertiary Extension within the Alpine Orogen (eds Durand, B. & Jolivet, L.), pp. 1536. Geological Society of London, Special Publication no. 156.Google Scholar
Sinclair, H. D. 1997. Tectonostratigraphic model for underfilled peripheral foreland basins: an Alpine perspective. Geological Society of America Bulletin 109, 324–46.2.3.CO;2>CrossRefGoogle Scholar
Sinclair, H. D. 2000. Delta-fed turbidites infilling topographically complex basins: a new depositional model for the Annots Sandstones. Journal of Sedimentary Research 70, 504–19.CrossRefGoogle Scholar
Sissingh, W. 2001. Tectonostratigraphy of the West Alpine Foreland: correlation of Tertiary sedimentary sequences, changes in eustatic sea-level and stress regimes. Tectonophysics 333, 361400.CrossRefGoogle Scholar
Spear, F. S. 1993. Metamorphic Phase Equilibria and Pressure-Temperature-Time Paths. Washington, DC: Mineralogical Society of America, 799 pp.Google Scholar
Sue, C. & Tricart, P. 2003. Neogene to ongoing normal faulting in the inner western Alps. Tectonics 22, doi:10.1029/2002TC001426.CrossRefGoogle Scholar
Thomas, J. C., Claudel, M. E., Collombet, M., Tricart, P., Chauvin, A. & Dumont, T. 1999. First paleomagnetic data from the sedimentary cover of the French Penninic Alps: evidence for Tertiary counterclockwise rotations in the Western Alps. Earth and Planetary Science Letters 171, 561–74.CrossRefGoogle Scholar
Tricart, P. 1984. From passive margin to continental collision: a tectonic scenario for the Western Alps. American Journal of Science 284, 97120.CrossRefGoogle Scholar
Tricart, P., Lardeaux, J.-M., Schwartz, S. & Sue, C. 2006. The late extension in the inner western Alps: a synthesis along the south-Pelvoux transect. Bulletin de la Société Géologique de France 177, 299310.CrossRefGoogle Scholar
Tricart, P. & Lemoine, M. 1986. From faulted blocks to megamullions and megaboudins-Tethyan heritage in the structure of the western Alps. Tectonics 5, 95118.CrossRefGoogle Scholar
Tricart, P. & Schwartz, S. 2006. A north-south section across the Queyras Schistes lustres (Piemont zone, Western Alps): syn-collision refolding of a subduction wedge. Eclogae Geologicae Helvetiae 99, 429–42.CrossRefGoogle Scholar
Tricart, P., Schwartz, S., Sue, C. & Lardeaux, J. M. 2004. Evidence of synextension tilting and doming during final exhumation from analysis of multistage faults (Queyras Schistes lustres, Western Alps). Journal of Structural Geology 26, 1633–45.CrossRefGoogle Scholar
Ulmer, P. & Trommsdorff, V. 1995. Serpentinite stability to mantle depths and subduction related magmatism. Science 268, 858–61.CrossRefGoogle Scholar
Vignaroli, G., Faccenna, C., Jolivet, L., Piromallo, C. & Rossetti, F. 2008. Subduction polarity reversal at the junction between the Western Alps and the Northern Apennines, Italy. Tectonophysics 450, 3450.CrossRefGoogle Scholar
Wicks, F. J. & O'Hanley, D. S. 1988. Serpentine minerals: structures and petrology. In Hydrous Phyllosilicates (ed. Bailey, S. W.), pp. 91167. Washington, DC: Mineralogical Society of America.CrossRefGoogle Scholar
Wunder, B. & Schreyer, W. 1997. Antigorite: high pressure stability in the system MgO-SiO2-H2O (MSH). Lithos 41, 213–27.CrossRefGoogle Scholar
Yamato, P., Agard, P., Burov, E., Le Pourhiet, L., Jolivet, L. & Tiberi, C. 2007. Burial and exhumation in a subduction wedge: mutual constraints from thermomechanical modeling and natural P-T-t data (Schistes Lustres, western Alps). Journal of Geophysical Research–Solid Earth 112, B07410, doi:10/1029/2006JB004441.CrossRefGoogle Scholar