Advertisement

Geologische Rundschau

, Volume 81, Issue 3, pp 655–668 | Cite as

The evolution of the Western Ligurian Flysch Units and the role of mud diapirism in ancient accretionary prisms (Maritime Alps, Northwestern Italy)

  • A. Di Giulio
Article

Abstract

The Western Ligurian Flysch Units represent an Upper Cretaceous to Paleogene accretionary prism overthrust onto the paleo-European continental margin during the collisional stages of the Alpine orogeny (Eocene). Their precollisional evolution has been reconsidered according to the data collected through extensive field mapping, the study of lowgrade metamorphism and by considering more strictly the processes documented in modern convergent zones.

The proposed model involves chaotic facies produced by the flow of muddy sediments along decollement surfaces (diapiric melange) with the growth of mud volcanoes into an accreting wedge progressively shifting toward the European continental margin.

Keywords

Eocene Continental Margin Paleogene Orogeny Accretionary Prism 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Zusammenfassung

Der westliche Ligurische Flysch repräsentiert die Entwicklung eines Akkretionskeiles während des Kreide-Paleogens, das auf den europäischen Kontinentalrand während der Kollisionsphase der alpidischen Orogenese (Eozän) überschoben wurde. Die Entwicklung vor der Kollision wird neu gedeutet auf der Basis ausgedehnter geologischer Felduntersuchungen, dem Studium der niedrig gradigen Metamorphose und anhand von Vergleichen mit heutigen konvergenten Zonen.

Das vorgeschlagene Modell interpretiert das Erscheinen der chaotischen Fazies als Diapirismus von nur teilweise verfestigten Sedimenten und deren Umlagerung nahe Diskontinuitätsflächen im Inneren eines Akkretionprismas, das in Richtung des europäischen Kontinents wandert.

Résumé

Les flyschs de la Ligurie occidentale représentent un prisme d'accrétion du Crétacé-Paléogène charrié sur la marge continentale européenne pendant les phases de collision de l'orogenèse alpine (Eocène). Leur évolution anté-collision est reconsidérée sur la base de nouvelles données provenant du levé de terrain d'une vaste région, de l'étude du métamorphisme de degré faible et de l'application plus rigoureuse des enseignements fournis par les zones de convergence actuelles.

Le modèle proposé envisage la production de facies à texture chaotique par flux diapirique de sédiments non consolidés le long de surfaces de décollement, à l'intérieur d'un prisme d'accrétion qui migre progressivement vers la marge continentale européenne.

Краткое содержание

Западная область Лиг урийского флиша — это аккреционный клин, об разовавшийся в перио д мела-палеогена и надв инувшийся на материк овый край Европы во время ф азы коллизии альпийс кого орогенеза в эоцене. На основании обширного геологиче ского исследования, и зучения метаморфизма низкой степени и сравнения с современными зонам и конвергенции разви тие этой области получил о иное толкование.

Предложенная модель объясняет появление хаотической фации, ка к следствие образова ния диапировых структур ных элементов в части чно сцементированных се диментах и их переотл ожение вблизи поверхностей несогласия внутри призмы аккреции, кото рая передвинулась в направлении европей ского материка.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Abbate, E.,Bortolotti, V. &Sagri, M. (1981): An approach to olistostrome interpretation. - I.A.S. 2nd European Regional Meeting, Bologna Excursion Guidebook, 165–185.Google Scholar
  2. Barber, J.A., Tjokrosapoetro, S. &Charlton, T.R. (1986): Mud volcanoes, shale diapirs, wrench faults and melanges in accretionary complexes, Eastern Indonesia. - AAPG Bull.,70, 1729–1741.Google Scholar
  3. Biju-Duval, B., Le Quellec, P., Mascle, A., Renard, V. &Valery, P. (1982): Multibeam bathimetric survey and high resolution seismic investigations on the Barbados Ridge Complex (Eastern Caribbean): a key to the knowledge and interpretation of an accretionary wedge. - Tectonophysics,86, 275–304.Google Scholar
  4. Bonazzi, A., Cobianchi, M. &Galbiati, B. (1987): Primi dati sulla cristallinità dell'illite nelle unità tettoniche più esterne e strutturalmente elevate delle Alpi liguri. - Atti Tic. Sc. Terra,31, 63–77.Google Scholar
  5. —, &Costa, E. (1989): Rapporto tra deformazione tettonica e cristallinità dell'illite nell'Appennino settentrionale - Atti Tic. Sc. Terra,32, 57–70.Google Scholar
  6. Boni, A &Vanossi, M. (1972): Carta geologica dei terreni compresi tra il Brianzonese ligure s.l. ed il Flysch ad Elmintoidi s.s. - Atti Ist. Geol. Univ. Pavia,23, tav. 24.Google Scholar
  7. Breen, N.A., Silver, E.A. &Hussong, D.M. (1986): Structural styles of an accretionary wedge south of the island of Sumba, Indonesia, revealed by SeaMARC II side scan sonar. - Geol. Soc. Am. Bull.,97, 1250–1261.Google Scholar
  8. Brizio, D.,De Regibus, C.,Eusebio, A.,Gallo, M.,Gosso, G.,Rattalino, E.,Rossi, F. &Tosetto, S. (1983): Structural map of the Southwestern sector of the Marguareis Massif (Ligurian Alps). - Mem. Soc. Geol. lt.,25, tav. 1.Google Scholar
  9. Brown, K. &Westbrook, G. K. (1988): Mud diapirism and subcretion in the Barbados Ridge Accretionary Complex: the role of fluids in accretionary processes. - Tectonics,7, 613–640.Google Scholar
  10. Caron, C., Hesse., Kerckhove, C., Homewood, P., van Stuijvenberg, J., Tasse, N. &Winkler, W. (1981) - Comparaison préliminaire des flyschs à Helminthoides sur troi transverales des Alpes. - Eclogae Geol. Helv.,74, 369–378.Google Scholar
  11. Cita, M. B., Camerlenghi, A., Erba, E., Mccoy, F.W., Castradori, D., Cazzani, A., Guasti, G., Giambastiani, M., Lucchi, R., Nolli, V., Pezzi, G., Redaelli, M., Rizzi, E., Torricelli, S. &Violanti, D. (1989): Discovery of mud diapirism on the Mediterranean Ridge. A Preliminary report. - Boll. Soc. Geol. lt.,108, 537–543.Google Scholar
  12. —,Ryan, W.F.B. &Paggi, L. (1981): Prometheus mud breccia: an example of shale diapirism in the western Mediterranean Ridge. - Ann. Geol. Pays Hellen.,30, 543–570.Google Scholar
  13. Cobianchi, M. (1984–5): Ricerche sui Flysch della Liguria Occidentale - Unpublished thesis, Pavia University.Google Scholar
  14. Cortesogno, L., Di Giulio, A., Galbiati, B. &Vannucci, R. (1988): Volcanic rocks into Western Ligurian Flysch: petrographic-geochemical data and paleogeographic significance. - Geol. Alpine Mem.,14, 179–195.Google Scholar
  15. Di Giulio, A. (1986): Sull'età terziaria dei Calcari di Ubaga, Successione di Borghetto d'Arroscia-Alassio (Alpi Marittime). -Riv. lt. Paleont. Strat.,92, 251–260.Google Scholar
  16. — (1988): Structural evolution of the San Remo and Moglio-Testico Units (Piedmontais-Ligurian Flysch, Maritime Alps): abstract - Rend. Soc. Geol. lt.,11, 61–64.Google Scholar
  17. Galbiati, B. (1984) - L'Unità di Borghetto ed i suoi legami con quella di Moglio-Testico (Alpi liguri): conseguenze paleogeografiche. - Riv. lt. Paleont. Strat.,90, 205–226.Google Scholar
  18. — (1986): L'Unità di Borghetto d'Arroscia-Alassio. - Mem. Soc. Geol. lt.,28, 181–210.Google Scholar
  19. — (1987): Assetto strutturale dell'elemento di Arnasco (Alpi liguri). - Boll. Soc. Geol. lt.,106, 745–755.Google Scholar
  20. —,Oxilia, M. &Seno, S. (1983): Aspetti stratigrafici e strutturali dell'elemento di Borghetto d'Arroscia (Alpi Marittime). - Riv. lt. Paleont. Strat.,89, 119–134.Google Scholar
  21. Henry, P., Le Pichon, X., Lallemant, S., Foucher, J.P., Westbrook, G. &Hobart, M. (1990): Mud volcano field seaward of the Barbados Accretionary Complex: a deep-towed side scan sonar survey.- J. Geophys. Res.,95, B/6, 8917–8929.Google Scholar
  22. Homewood, P. &Caron, C. (1982): Flysch of the Western Alps. - In: „Mountain Building Processes“ (K. J. Hsü, Ed.), 157–168.Google Scholar
  23. Hsü, K. (1974): Melanges and their distinction from olistostromes. - In: „Modern and ancient geosinclinal sedimentation“ (Dott, R. & Shaver, R., Eds.), 321–333.Google Scholar
  24. Jarrad, R.D. (1986): Causes of compression and extension behind trenches. - Tectonophysics,132, 89–102.Google Scholar
  25. Kubler, B. (1968): Evaluation quantitative du metamorphisme par la cristallinité dell'illite. - Bull. Centre Rech. pau-SNPA,2, 385–397.Google Scholar
  26. Kulm, L. D., Suess, E., Moore, J.C., Carson, B., Lewis, B.T., Ritiger, S.D., Kaolko, D.C., Thornburg, T.M., Embey, R.W., Rugh, W.D., Massoth, C.J., Langseth, M.G., Cohcrane, G.R. &Scamman, R.L. (1986): Oregon subduction zone: venting, fauna and carbonates. - Science,231, 561–566.Google Scholar
  27. Lallemant, S., Chamot-Rooke, N., Le Pichon, X. &Randgine, C. (1989): Zenisu Ridge: a deep intraoceanic thrust related to subduction, off Southwest Japan. - Tectonophysics,160, 151–174.Google Scholar
  28. Langseth, M.G. &Moore, J.C. (1990): Introduction to special section on the role of fluids in sediment accretion, deformation, diagenesis, and metamorphism in subduction zones. -J. Geophys. Res.,95, B/6, 8737–8741.Google Scholar
  29. —,Westbrook, G.K. &Hobart, M.A. (1988): Geophysical survey of a Mud volcano seaward of the Barbados Ridge Accretionary Complex. - J. Geophys. Res.,93, B/2, 1049–1061.Google Scholar
  30. Lanteaume, M. (1968): Contribution a l'étude géologique des Alpes Maritimes franco-italiennes. - Mém. Carte Géol. Fr., 405 pp.Google Scholar
  31. Le Pichon, X., Foucher, J.P., Boulegue, J., Henry, P., Lallemant, S., Benedetti, M., Avedik, F. &Mariotti, A. (1990): Mud volcano field seaward of the Barbados Accretionary Complex: a submersible survey. - J. Geophys. Res.,95, B/6, 8931–8943.Google Scholar
  32. —,Iigamce, T., Boulegue, J., Charret, J., Faure, M., Kano, K., Okada, H., Rangin, C., Taira, A., Urabe, T. &Uyeda, S. (1987): Nankai trough and Zenisu Ridge: a deep-sea submersible survey. - Earth Planet. Sci. Lett.,83, 285–299.Google Scholar
  33. Manivit, H. &Prud' Homme, A. (1990): Biostratigrafie du Flysch a Helminthoides des Alpes maritimes francoitaliennes. Nannofossiles de l' unité de San Remo-Monte Saccarello. Comparaison avec les Flyschs à Helminthoides des Apennins. Bull. Soc. Geol. France,8, VI, 95–104.Google Scholar
  34. Mascle, A.,Biju-Duval, B.,De Clarens, P. &Munsch, H. (1986): Growth of accretionary prisms: tectonic processes from Caribbean examples. - In: „The origin of arcs“ (Wezel, F., Ed.), 375–400.Google Scholar
  35. Moore, J.C. (1989): Tectonics and hydrogeology of accretionary prisms: role of the decollement zone. - Jour. Struct. Geol.,11, 95–106.Google Scholar
  36. Orange, D.L. (1990): Criteria helpful in recognizing shear-zone and diapiric melanges: examples from the Hoh accretionary complex, Olympic Peninsula, Washington. - Geol. Soc. Am. Bull.,102, 935–951.Google Scholar
  37. Polino, R., Dal Piaz, G.V. &Gosso, G. (1990): Tectonic erosion at the Adria margin and accretionary processes for the Cretaceous orogeny of the Alps. - Vol. spec. Soc. Geol. lt.,1, 345–367.Google Scholar
  38. Sagri, M. (1984): Litologia, stratimetria e sedimentologia delle torbiditi di piana di bacino del Flysch di San Remo (Cretaceo superiore, Liguria occidentale). - Mem. Soc. Geol. lt.,28, 577–586.Google Scholar
  39. Shipley, T., Stoffa, P.L. &Dean, D.F. (1990): Underthrust sediments, fluid migration paths and mud volcanoes associated with the accretionary wedge off Costa Rica: Middle American Trench. - J. Geophys. Res.,95, B/6, 8743–8752.Google Scholar
  40. Shouldice, D.H. (1971): Geology of the western Canadian continental shelf. - Bull. Can. Petr. Geol.,19, 405–436.Google Scholar
  41. Silver, E.A. &Beutner, E.C. (1980): Melanges - Geology,8, 32–34.Google Scholar
  42. — &Reed, D.L. (1988): Backthrusting in accretionary wedges.- J. Geophys. Res.,93, B/4, 3116–3126.Google Scholar
  43. Snavely, P.D.,Pearl, J.E. &Lander, D.L. (1977): Interim report on petroleum resources, potential and geological hazards in the outer continental shelf, Oregon and Washington Tertiary Province. - U.S. Open file report, 77–282, 63 pp.Google Scholar
  44. Speed, R. (1990): Volume loss and defluidization history of Barbados. - J. Geophys. Res.,95, B/6, 8983–8996.Google Scholar
  45. Stampfli, G. M. &Marthaler, M. (1990): Divergent and convergent margins in the North-Western Alps: confrontation to actualistic models. - Geodinamica Acta,4, 3, 159–184.Google Scholar
  46. Stride, A., Balderson, R. &Kenyon, N. (1982): Structural grain, mud volcanoes and other features on the Barbados Ridge Complex, revealed by Gloria long-rang side-scan sonar. - Marine Geology,49, 187–196.Google Scholar
  47. Vanossi, M. (1980): Les unités géologiques des Alpes Maritimes entre l'Ellero et la Mer Ligure: un apercu schematique. - Mem. Soc. Geol. Univ. Padova,34, 101–142.Google Scholar
  48. —,Cortesogno, L., Galbiati, B., Messiga, B., Piccardo, G. &Vannucci, R. (1986): Geologia delle Alpi liguri: dati, problemi ipotesi - Mem. Soc. Geol. lt.,28, 5–75.Google Scholar
  49. Von Huene, R. &Lee, H. (1982): The possible significance of pore fluid pressures in subduction zones.- AAPG Mem.,34, 781–791.Google Scholar
  50. Westbrook, G.K. &Smith, M.J. (1983): Long decollements and mud volcanoes: evidence from the Barbados Ridge Complex for the role of high pore-fluid pressure in the development of an accretionary complex. - Geology,11, 279–283.Google Scholar
  51. Williams, P.R., Pingram, C.J. &Dow, D.B. (1984): Melange production and the importance of shale diapirism in accretionary terranes. - Nature,309, 145–146.Google Scholar

Copyright information

© Ferdinand Enke Verlag Stuttgart 1992

Authors and Affiliations

  • A. Di Giulio
    • 1
  1. 1.Dipartimento di Scienze della TerraUniversità di PaviaPaviaItaly

Personalised recommendations