Why do continents break-up parallel to ancient orogenic belts?
Corresponding Author
A. Vauchez
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
*Correspondence: A. Vauchez, E-mail: [email protected]Search for more papers by this authorG. Barruol
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
Search for more papers by this authorA. Tommasi
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
also at Lab. Petrologie et Tectonique. Université Lyon I & CNRS, France
Search for more papers by this authorCorresponding Author
A. Vauchez
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
*Correspondence: A. Vauchez, E-mail: [email protected]Search for more papers by this authorG. Barruol
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
Search for more papers by this authorA. Tommasi
Laboratoire de Tectonophysique, Université de Montpellier II & CNRS, F–35095 Montpellier Cedex 05, France
also at Lab. Petrologie et Tectonique. Université Lyon I & CNRS, France
Search for more papers by this authorABSTRACT
The frequently observed parallelism between rifts and the preexisting orogenic fabric of continents suggests that the inherited tectonic fabric of the lithosphere influences the rupture of continents. We propose that the existence of a pervasive fabric in the lithospheric mantle induces an anisotropic strength in the lithosphere, that guides the propagation of continental rifts. Subcrustal mantle mechanical anisotropy is supported by (i) the anisotropic strength of olivine, (ii) an ubiquitous tectonic fabric in exposed mantle rocks, and (iii) measurements of seismic and electrical anisotropy. During major episodes of continent assembly, a pervasive deformation of the lithosphere induces a lattice-preferred orientation of olivine in mantle rocks. Later on, this crystallographic fabric is ‘frozen-in’ and represents the main source of shear wave splitting. This olivine fabric may entail a mechanical anisotropy in the lithospheric mantle. During subsequent tectonic events, especially during rifting, mechanical anisotropy may control the tectonic behaviour of the lithosphere
References
- Bai, Q., Mackwell, S.J. and Kohlstedt, D.L., 1991. High-temperature creep of olivine single crystals. 1. Mechanical results for buffered samples. J. geophys. Res., 96, 2441–2463.
- Barruol, G., Silver; P.G. and Vauchez, A., 1997. Seismic Anisotropy In The Eastern US: Deep Structure Of a Complex Continental Plate. J. geophys. Res., 102, 8329–8348.
- Barruol, G. and Souriau, A., 1995. Anisotropy beneath the Pyrenees range from teleseismic shear wave splitting. Geophys. Res. Lett., 22, 493–496.
- Bonatti, E., 1996. Anomalous opening of the Equatorial Atlantic due to an equatorial mantle thermal minimum. Earth Planet. Sci. Lett., 143, 147–160.
- Burke, K.C., 1976. Development of graben associated with the initial ruptures of the Atlantic ocean. Tectonophysics, 36, 93–112.
- Chang, H.K., Kowsmann, R.O., Figueiredo, A.M.F. and Bender, A.A., 1992. Tectonics and stratigraphy of the East Brazil Rift system: an overview. Tectonophysics, 213, 97–138.
- Choukroune, P., 1992. Tectonic evolution of the Pyrenees. Ann. Rev. Earth Planet. Sci., 20, 143–158.
- Cook, F.A., Albaugh, D.S., Brown, L.D., Oliver, J.E. and Hatcher, R.D., 1979. Thin-skinned tectonics in the crystalline southern Appalachians; COCORP seismic-reflection profiling of the Blue Ridge and Piedmont. Geology, 7, 563–567.
- Delvaux, D., Moeys, R., Stapel, G., Melnikov, A. and Ermikov, V., 1995. Paleostress reconstructions and geodynamics of the Baikal region, Central Asia. Part II: Paleozoic and Cenozoic prerift evolution. Tectonophysics, 252, 61–101.
- Doser, D.I. and Yardwood, R., 1991. Strike-slip faulting in continental rifts: examples from Sabukia, East Africa (1928), and other regions. Tectonophysics, 197, 213–224.
- Dunbar, J.A. and Sawyer, D.S., 1989. How preexisting weaknesses control the style of continental breakup. J. geophys. Res., 94, 7278–7292.
- Durham, W.B. and Goetze, G., 1977. Plastic flow of oriented single crystals of olivine. I. Mechanical data. J. geophys. Res., 82, 5737–5753.
- Fairhead, J.D. and Binks, R.M., 1991. Differential opening of the Central and South Atlantic oceans and the opening of the West African rift system. Tectonophysics, 187, 191–203.
-
Hoffman, P.F., 1989. Precambrian geology and tectonic history of North America. In: The Geology of North America An overview ( A. W. Bally and
A. R. Palmer, eds), Pp.
447–512. The Geological Society of America,
Boulder
,
CO
.
10.1130/DNAG-GNA-A.447 Google Scholar
- Lebensohn, R.A. and Tomé, C.N., 1993. A self-consistent anisotropic approach for the simulation of plastic deformation and texture development of polycrystals: Application to zirconium alloys. Acta mater., 41, 2611–2624.
- Ma, Xingyuan and Wu, Daning, 1987. Cenozoic extensional tectonics in China. Tectonophysics, 133, 243–255.
- Mainprice, D. and Silver, P.G., 1993. Interpretation of SKS-waves using samples from the subcontinental lithosphere, Phys. Earth Planet. Int., 78, 257–280.
- Mercier, J.-C. and Nicolas, A., 1975. Textures and fabrics of upper mantle peridotites as illustrated by xenoliths from basalts. J. Petrol., 16, 454–487.
- Nicolas, A. and Christensen, N.I., 1987. Formation of anisotropy in upper mantle peridotites—A review. In: Composition, Structure and Dynamics of the Lithosphere-Asthenosphere System ( K. Fuchs and C. Froidevaux, eds), Pp. 111–123. American Geophysical Union, Washington , D.C .
- Nicolas, A. and Poirier, J.P., 1976. Crystalline Plasticity and Solid State Flow in Metamorphic Rocks. Wiley, London , 444 Pp.
- Ogawa, Y., Jones, A.G., Unsworth, M.J., Booker, J.R., Lu, X.Y., Craven, J., Roberts, B., Parmelee, J. and Farquharson, C., 1996. Deep electrical conductivity structures of the Appalachian Orogen in the southeastern US. Geophys. Res. Lett., 23, 1597–1600.
- Olsen, K.H., Baldridge, W.S. and Callender, J.F., 1987. Rio Grande Rift: An overview. Tectonophysics, 143, 119–39.
- Piqué, A. and Laville, E., 1996. The central Atlantic rifting: reactivation of Palaeozoic structures J. Geodynamics, 21, 235–255.
- Ring, U., 1994. The influence of preexisting structure on the evolution of the Cenozoic Malawi rift (East African rift system). Tectonics, 13, 313–326.
- Sénéchal, G., Rondenay, S., Mareschal, M., Guilbert, J. and Poupinet, G., 1996. Seismic and electrical anisotropies in the lithosphere across the Grenville Front. Canada. Geophys. Res. Lett., 23, 2255–2258.
- Silver, P.G., 1996. Seismic anisotropy beneath the continents: Probing the depths of geology. Ann. Rev Earth Planet. Sci., 24, 385–432.
- Sirieys, P.M., 1982. Anisotropie mecanique des roches. In: Mechanical Behavior of Anisotropic Solids ( J. P. Boehler, ed.). Pp. 481–532. Martinus Nijhof, The Hague. Centre National de la Recherche Scientifique, Paris .
- Theunissen, K., Klerkx, J., Melnikov, A. and Mruma, A., 1996. Mechanisms of inheritance of rift faulting in the western branch of the East African Rift, Tanzania. Tectonics, 15, 776–790.
- Tommasi, A., Vauchez, A. and Daudré, B., 1995. Initiation and propagation of shear zones in a heterogeneous continental lithosphere. J. geophys. Res., 100, 22.083–22, 101.
- Ussami, N., Sa, N.C. and Molina, E.C., 1993. Gravity map of Brazil. 2, regional and residual isostatic anomalies and their correlation with major tectonic provinces. J. geophys. Res., 98, 2199–2208.
- Vauchez, A. and Barruol, G., 1996. Shear waves splitting in the Appalachians and the Pyrenees: Importance of the inherited tectonic fabric of the lithosphere. Plys. Earth Planet. Int., 95. 127–138.
- Wilson, J.T., 1966. Did the Atlantic close and then re-open?. Nature, 211, 676–681.
-
Worral, D.M. and
Snelson, S., 1989. Evolution of the northern Gulf of Mexico, with emphasis on Cenozoic growth faulting and the role of salt. In: The Geology of North America—An overview ( A. W. Bally and
A. R. Palmer, eds), Pp.
97–138. The Geological Society of America,
Boulder
,
CO
.
10.1130/DNAG-GNA-A.97 Google Scholar
- Zwart, H.J., 1986. The Variscan geology of the Pyrenees. Tectonophysics. 129, 9–27.
