Abstract
The anisotropy of magnetic susceptibility, coupled with geochemical identification of magma sources, has been investigated in 360 samples from 67 basaltic dikes of the sheeted dike complex of the Oman ophiolite. Two thirds of the analysed dikes have MORB affinities, while the others, previously related to island arc setting, show REE patterns and trace elements evolution more in agreement with an off-axis ridge magmatism and an interaction between magma and ultramafic country rocks. Only half of the dikes yield primary flow fabrics with a minimum magnetic axis K3 close to dike pole and a maximum axis Kl parallel to flow line. Secondary fabrics, mainly with Kl parallel to dike pole, are more likely to occur in thick (≥1.5 m) dikes with high susceptibility and MORB composition. Flow lines appear quite dispersed with an overall tendency toward vertical flow. Dikes of the end of emplacement. This shear could be a signature of oblique spreading during the accretion of the Omani oceanic crust MORB type composition show a distinct obliquity of their flow plane relative to dike margins, suggesting that the dikes were horizontally sheared at the end of emplacement. This shear could be a signature of oblique spreading during the accretion of the Omani oceanic crust.
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References
Alabaster, T., Pearce, J.A. and Malpas, J., 1982. The volcanic stratigraphy and petrogenesis of the Oman ophiolite Complex. Contrib. Mineral. Petrol., 82: 168–183.
Beurrier, M., Ohnenstetter, M., Cabanis, B., Lescuyer, J.L., Tegyey, M. and Le Métour, J., 1989. Géochimie des filons doléritiques et des roches volcaniques ophiolitiques de la nappe de Semail: contraintes sur leur origine géotectonique au Crétacé Supérieur. Bull. Soc. Géol. Fr., 8: 205–219.
Boudier, F., Bouchez, J.L., Nicolas, A., Cannat, M., Ceuleneer, G., Misseri M. and Montigny R., 1985. Kinematics of oceanic thrusting in the Oman ophiolite: model of plate convergence. Earth Planet. Sci. Lett., 75: 215–222.
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., Nicolas, A. and Ceuleneer, G., 1989. De l’accretion océanique à la convergence. Le cas de l’ophiolite d’Oman. Bull. Soc. Géol. France, 8: 221–230.
Coleman, R.G., 1981. Tectonic setting for ophiolite obduction in Oman. J. Geophys. Res., 86: 2497–2508.
Dauteuil, O., Brun, J.P., Avedik, F. and Geli, L., 1990. Structures of the oblique rifting in the Mohns ridge (Norwegian Sea), C.R. Acad. Sci. Paris, 311: 357–363.
Dawson, E.M. and Hargraves, R.B., 1985. Anisotropy of magnetic susceptibility as an indicator of magma flow directions in diabase dikes. EOS Trans. AGU, 66: 251.
Dosso, L., Bougault, H., Beuzart, P., Calvez, J.Y. and Joron, J.L., 1988. The geochemical structure of the South East Indian Ridge. Earth Planet. Sci. Lett., 88: 47–59.
Ellwood, B.B., 1978. Flow and emplacement directions determined for selected magmatic bodies using anisotropy of magnetic susceptibility measurements. Earth Planet. Sci. Lett., 41: 254–264.
Hrouda, F., 1982. Magnetic anisotropy of rocks and its application in geology and geophysics. Geophys. Surv., 5: 37–82.
Hrouda, F., 1985. The magnetic fabric of the Brno massif. Sbor. geol. ved, 19: 89–112.
Jeffrey, G.H., 1922. The motion of ellipsoidal particles emersed in a viscous fluid. Proc. R. Soc. London ser. A, 102: 161–179.
Jelinek, V., 1978. Statistical processing of anisotropy of magnetic susceptibility measured on group of specimens. Studia Geophys. Geodet., 22: 50–62.
Kelemen, P.B., Joyce, D.B., Webster, J.D. and Holloway, J.R., 1990. Reaction between ultramafic rock and fractionating basaltic magma - II - Experimental investigation of reaction between olivine tholeiite and harzburgite at 1150°-1050°C and 5 kb. J. Petrol., 31: 99–134.
Khan, M.A., 1962. The anisotropy of magnetic susceptibility of some igneous and metamorphic rocks, J. Geophys. Res., 67: 2873–2885.
Kidd, R.G.W. and Cann, J.R., 1974. Chilling statistics indicate on ocean floor spreading origin for the Troodos complex, Cyprus. Earth Planet. Sci. Lett., 24: 151–155.
Knight, M.D. and Walker, G.P., 1988. Magma flow directions in dikes of the Koolau complex, Oahu, determined from magnetic fabric studies. J. Geophys. Res., 93: 4301–4319.
Luyendick, B.P., Laws, B.R., Day, R. and Collinson, T.B., 1982. Paleomagnetism of the Samail ophiolite, Oman 1. The sheeted dike complex at Ibra. J. Geophys. Res., 87: 10883–10902.
Mc Culloch, M.T., Gregory, R.T., Wasserburg, G.J. and Taylor, H.P., 1981. Sm-Nd, Rb-Sr and O18/O16 isotopic systematics in an oceanic crustal section: evidence from the Samail ophiolite. J. Geophys. Res., 86: 2721–2735.
Michard, A., Montigny, R. and Schlich, R.. 1986. Geochemistry of the mantle beneath the Rodriguez Triple junction and the South-East Indian Ridge. Earth Planet. Sci. Lett., 78: 104–114.
Montigny, R., Le Mer, O., Thuizat, R. and Withechurch, H., 1988. K-Ar and 40Ar/39Ar study of metamorphic rocks asociated with the Oman ophiolite: tectonic implications. Tectonophysics, 151: 345–262.
Nehlig, P., 1989. Etude d’un système hydrothermal fossile: l’ophiolite de Semail (Oman). Thèse Doc. Univ. Brest, 308 p.
Nicolas, A.. 1989. Structures of ophiolites and dynamics of oceanic lithosphere. Kluwer ed., London, 367 pp.
Nicolas, A., Ceuleneer, G., Boudier, F. and Misseri, M., 1988a. Structural mapping in the Oman ophiolites: mantle diapirism along an oceanic ridge. Tectonophysics, 151: 27–56.
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.
Pallister, J.S., 1981. Structure of the sheeted dike complex of the Samail ophiolite near Ibra, Oman. J. Geophys. Res.. 86: 2661–2672.
Park, J.K., Tanczyk, E. and Desbarats, A., 1988. Magnetic fabric and its significance in the 1400 Ma Mealy diabase dikes of Labrador, Canada, J. Geophys. Res. 93: 4301–4319.
Pearce, J.A., Alabaster, T., Shelton, A.W. and Searle, M.P., 1981. The Oman ophiolite as a Cretaceous arc-basin complex: evidences and implications. Phil. Trans. R. Soc. London, 300: 299–317.
Pecher, A., 1989. Schmidt Mac, a program to display and analyse directionnal data. Computer & Geosciences. 15: 1315–1326.
Potter, D.K. and Stephenson, A., 1988. Single-domain particles in rocks and magnetic fabric analysis. Geophys. Res. Lett. 15: 1097–1100.
Rautenschlein, M., Jenner, G.A., Hertogen J., Hofmann A.W., Kerricn R., Schmincke, H.U. and White, W.M., 1985. Isotopic and trace element composition of volcanic glasses from the Akaki Canyon, Cyprus. implication for the origin of the Troodos ophiolite. Earth Planet. Sci. Lett.. 75: 369–383.
Reuber, I.. 1988. Complexity of the crustal sequence in northern Oman ophiolite (Fizh and southern Aswad block): the effect of early slicing ? Tectonophysics. 151: 137–165.
Rochette, P.. 1988. Inverse magnetic fabric in carbonate bearing rocks, Earth planet. Sci. Lett.. 90: 229–237.
Sempéré, J.C., Purdy, G.M. and Schouten, S., 1990. Segmentation of the Mid-Atlantic Ridge between 24°N and 30°40’N. Nature, 344: 427–431.
Shelton, A.W., 1984. Geophysical studies on the northern Oman ophiolite. Ph. D. Thesis, Open Univ. Milton Keynes, 353 pp.
Shelley, D., 1985. Determining paleo-flow directions from groundmass fabrics in the Lyttelton radial dikes. J. Volcanol Geotherm. Res., 25: 69–79.
Tapponnier, P., Armijo, R., Manighettti, I. and Courtillot, V., 1990. Bookshelf faulting and horizontal block rotations between overlapping rifts in southern Afar. Geophys. Res. Lett., 17: 1–4.
Thomas, V., Pozzi, J.P. and Nicolas, A., 1988. Paleomagnetic results from Oman ophiolites related to their emplacement. Tectonophysics, 151: 297–322.
Viereck, L.G., Flower, M.F.J., Hertogen, J., Schmincke, H.U. and Jenner, G.A., 1989. The genesis and significance of N-MORB sub-types. Contrib. Mineral. Petrol., 102: 112–126.
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Rochette, P., Jenatton, L., Dupuy, C., Boudier, F., Reuber, I. (1991). Diabase Dikes Emplacement in the Oman Ophiolite: A Magnetic Fabric Study with Reference to Geochemistry. In: Peters, T., Nicolas, A., Coleman, R.G. (eds) Ophiolite Genesis and Evolution of the Oceanic Lithosphere. Petrology and Structural Geology, vol 5. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3358-6_5
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DOI: https://doi.org/10.1007/978-94-011-3358-6_5
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