Abstract
Shear direction inversions in uppermost mantle flow are documented in several ophiolites. We relate such inversions to the forced flow away from the top of mantle diapirs. In the Oman ophiolite, however, the shear direction inversion is not systematically developed at the same level in the ophiolite sequence. In particular, in the vicinity of mantle diapirs, the uppermost mantle forced flow diverging from the diapir has a clear outward (top away from the diapir) direction of shear, whilst the inward (top toward the diapir) relative shear direction, due to the forced flow, seems to occur within the thick crystal mush of the overlying magma chamber. Conversely, away from diapirs, the inward shear direction is recorded in the top mantle section. A detailed study conducted in the peridotite section of the Hilti massif, presumably located at some distance to the South-East of its parent diapir, reveals that the shear direction inversion occurred at a variable depth with respect to the Moho. The observed structure suggests the existence of mantle flow channels just below the Moho, with comparatively more stagnant zones in between.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Abrams, M.J., Rothery, D.A. and Pontual, A., 1988. Mapping in the Oman ophiolite using enhanced thematic mapper images. Tectonophysics, 151: 387–401.
Billiau, S., 1993. Etude des écoulements asthénosphériques forcés au voisinage des diapirs mantelliques dans l’ophiolite d’Oman. Unpublished DEA, Université Montpellier II.
Boudier, F., Ceuleneer, G. and Nicolas, A, 1988. Shear zones, thrusts and related magmatism in the Oman ophiolite : initiation of thrusting on an oceanic ridge. Tectonophysics, 151: 275–296.
Boudier, F. and Nicolas, A., in press. Nature of the Moho transition zone in the Oman ophiolite. J. Petrol.
Cassard, D., 1980. Structure et origine des gisements de chromite du massif du Sud (ophiolite de Nouvelle Calédonie). Guides de prospection. Unpublished Thèse de 3° cycle, Université de Nantes.
Ceuleneer, G., 1991. Evidence for a paleo-spreading center in the Oman ophiolite: mantle structures in the Maqsad area. In: T. Peters, A. Nicolas and R. G. Coleman (Editors), Ophiolite genesis and evolution of the oceanic lithosphère. Kluwer Academic Publishers, Dordrecht, pp. 147–173.
Ceuleneer, G., Nicolas, A. and Boudier, F, 1988. Mantle flow patterns at an oceanic spreading centre: the Oman peridotites record. Tectonophysics, 151: 1–26.
Ernewein, M., Pflumio, C. and Whitechurch, H., 1988. The death of an accretion zone as evidenced by the magmatic history of the Sumail ophiolite. Tectonophysics, 151: 247–274.
MPM Oman, 1987. Geological map, Al Wasit, NG40–14E-III. Ministry of Petroleum and Minerals, Sultanate of Oman.
Girardeau, J. and Nicolas, A., 1981. Structures in two of the Bay of Islands (Newfoundland) ophiolite massifs: a model for oceanic crust and upper mantle. Tectonophysics, 77: 1–34.
Glennie, K.W., Boeuf, M.G.A., Hughes Clarke, M.W., Moody-Stuart, M., Pilaar, W.F.H. and Reinhardt, B.M., 1974. “Geology of the Oman mountains”. Verh. Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap, 31.
Hacker, B.R., McWilliams, M.O. and Mosenfelder, J.L, 1993. Rapid emplacement of the Oman ophiolite. IAVCEI Abstracts, Ancient volcanism and modern analogues, Canberra, p. 44.
Hoxha, M., 1993. Etude structurale et pétrologique de l’ophiolite de Kukes (Albanie): cinématique de la déformation et géométrie de la ride. Unpublished Thesis INPL, Université de Nancy.
Montigny, R., Le Mer, O., Thuizat, R. and Whitechurch, H., 1988. K-Ar and 40Ar/39Ar study of meta-morphic rocks associated with the Oman ophiolite: tectonic implications. Tectonophysics, 151: 345–362.
Nicolas, A., 1989. Structures in ophiolites and dynamics of oceanic lithosphère. Kluwer Academic Publishers, Dordrecht, 367 pp.
Nicolas, A., 1992. Kinematics in magmatic rocks with special reference to gabbros. J. Petrology, 33: 891–915.
Nicolas, A. and Boudier, F., in press. Mapping mantle diapirs and oceanic crust segments in Oman ophiolites. J. Geophys. Res.
Nicolas, A., Boudier, F. and Ildefonse, B., in press. Evidence from the Oman ophiolite for active mantle upwelling beneath a fast-spreading ridge. Nature.
Nicolas, A. and Poirier, J.P, 1976. Crystalline plasticity and solid-state flow in metamorphic rocks. Wiley-Interscience, London, 444 pp.
Nicolas, A., Reuber, I. and Benn, K., 1988. A new magma chamber model based on structural studies in the Oman ophiolite. Tectonophysics, 151: 87–105.
Nicolas, A. and Violette, J.F., 1982. Mantle flow at oceanic spreading centers: models derived from ophiolites. Tectonophysics, 81: 319–339.
Podvin, P., 1983. Remobilisations chimiques successives dans les tectonites ophiolitiques et leurs gisements de chromite. Exemple du massif du Humboldt, Nouvelle Calédonie. Unpublished thèse Doc. Ing., Ecole Nat. Sup. Mines, Paris.
Prinzhofer, A., Nicolas, A., Cassard, D., Moutte, J., Leblanc, M., Paris, P. and Rabinovitch, M., 1980. Structures in the New Caledonia peridotite-gabbros: implications for oceanic mantle and crust. Tectonophysics, 69: 85–112.
Rabinowicz, M., Ceuleneer, G. and Nicolas, A., 1987. Melt segregation and flow in mantle diapirs below spreading centers : evidence from the Oman ophiolite. J. Geoph. Res., 92: 3475–3486.
Rabinowicz, M., Nicolas, A. and Vigneresse, J.L., 1984. A rolling mill effect in asthenosphere beneath oceanic spreading centers. Earth Planet. Sei. Letters, 67: 97–108.
Reuber, I., 1991. Geometry and flow pattern of the plutonic sequence of the Salahi massif (Northern Oman Ophiolite) — A key to decipher successive magmatic events. In: T. Peters, A. Nicolas and R. G. Coleman (Editors), Ophiolite genesis and evolution of the oceanic lithosphère. Kluwer Academic Publishers, Dordrecht, pp. 83–103.
Suhr, G., 1992. Upper mantle peridotites in the Bay of Islands ophiolite, Newfoundland: formation during the final stages of a spreading centre? Tectonophysics, 206: 31–53.
Violette, J.F., 1980. Structure des ophiolites des philippines (Zambales et Palawan) et de Chypre. Ecoulement asténosphérique sous les zones d’expansion océaniques. Unpublished Thèse de 3° cycle, Université de Nantes.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1995 Springer Science+Business Media Dordrecht
About this paper
Cite this paper
Ildefonse, B., Billiau, S., Nicolas, A. (1995). A Detailed Study of Mantle Flow away from Diapirs in the Oman Ophiolite. In: Vissers, R.L.M., Nicolas, A. (eds) Mantle and Lower Crust Exposed in Oceanic Ridges and in Ophiolites. Petrology and Structural Geology, vol 6. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-8585-9_7
Download citation
DOI: https://doi.org/10.1007/978-94-015-8585-9_7
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-4557-7
Online ISBN: 978-94-015-8585-9
eBook Packages: Springer Book Archive