Abstract
The main Ethiopian rift is an active rift in the break-up stage, and it marks the incipient boundary between the Nubia and Somalia plates1. Rifting started with the activation of large boundary faults and diffuse volcanism, followed by focused magmatism and faulting in the rift floor, along step-like segments oblique to the rift axis that now act as a protoridge for future seafloor spreading2. This concentration of volcano-tectonic activity has been thought to be either magma assisted2,3 or controlled by a change in rift kinematics, with a late oblique rifting phase that would have caused the development of the step-like fault segments that focused magma upwelling4,5. Geodetic6,7, seismic8 and stress-field9 data confirm current oblique rifting kinematics, but plate kinematics models do not predict a change in Nubia–Somalia motion in the past 11 million years10. Here, I use lithospheric-scale analogue models of oblique rifting to analyse the development of the main Ethiopian rift. I find that neither magma weakening nor a change in plate kinematics are required to simulate a two-phase evolution with successive activation of differently oriented fault systems. I conclude that rift evolution and segmentation are controlled by rift obliquity, independent of magmatic processes.
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References
Ebinger, C. Continental breakup: The East African perspective. Astron. Geophys. 46, 2.16–2.21 (2005).
Ebinger, C. J. & Casey, M. Continental breakup in magmatic provinces: An Ethiopian example. Geology 29, 527–530 (2001).
Kendall, J. M., Stuart, G. W., Ebinger, C. J., Bastow, I. D. & Keir, D. Magma-assisted rifting in Ethiopia. Nature 433, 146–148 (2005).
Bonini, M., Souriot, T., Boccaletti, M. & Brun, J. P. Successive orthogonal and oblique extension episodes in a rift zone: Laboratory experiments with application to the Ethiopian Rift. Tectonics 16, 347–362 (1997).
Boccaletti, M., Bonini, M., Mazzuoli, R. & Trua, T. Plio-Quaternary volcanotectonic activity in the northern sector of the Main Ethiopian Rift: Relationships with oblique rifting. J. Afr. Earth Sci. 29, 679–698 (1999).
Bilham, R. et al. Secular and tidal strain across the Ethiopian rift. Geophys. Res. Lett. 297, 2789–2984 (1999).
Fernandes, R. M. S. et al. Angular velocities of Nubia and Somalia from continuous GPS data: Implications on present-day relative kinematics. Earth Planet. Sci. Lett. 222, 197–208 (2004).
Keir, D., Ebinger, C. J., Stuart, G. W., Daly, E. & Ayele, A. Strain accommodation by magmatism and faulting as rifting proceeds to breakup: Seismicity of the northern Ethiopian rift. J. Geophys. Res. 111, B05314 (2006).
Bosworth, W., Strecker, M. R. & Blisniuk, P. M. Integration of east African Paleostress and present-day stress data: Implications for continental stress field dynamics. J. Geophys. Res. 97, 11851–11865 (1992).
Royer, J.-Y., Gordon, R. G. & Horner-Johnson, B. C. Motion of Nubia relative to Antarctica since 11 Ma: Implications for Nubia–Somalia, Pacific–North America, and India-Eurasia motion. Geology 34, 501–504 (2006).
Mohr, P. The Ethiopian Rift System. Bull. Geophys. Obs. Addis Ababa 5, 33–62 (1962).
Gibson, I. L. The structure and volcanic geology of an axial portion of the Main Ethiopian Rift. Tectonophysics 8, 561–565 (1969).
Boccaletti, M., Bonini, M., Mazzuoli, R., Abebe, B. & Piccardi, G. Quaternary oblique extensional tectonics in the Ethiopian Rift (Horn of Africa). Tectonophysics 287, 97–116 (1998).
Mackenzie, G. H., Thybo, G. H. & Maguire, P. Crustal velocity structure across the Main Ethiopian Rift: Results from 2-dimensional wide-angle seismic modelling. Geophys. J. Int. 162, 996–1006 (2005).
WoldeGabriel, G., Aronson, J. L. & Walter, R. C. Geology, geochronology, and rift basin development in the central sector of the Main Ethiopian Rift. Geol. Soc. Am. Bull. 102, 439–458 (1990).
Wolfenden, E., Ebinger, C., Yirgu, G., Deino, A. & Ayale, D. Evolution of the northern Main Ethiopian rift: Birth of a triple junction. Earth Planet. Sci. Lett. 224, 213–228 (2004).
Bonini, M. et al. The evolution of the Main Ethiopian Rift in the frame of Afar and Kenya rifts propagation. Tectonics 24, TC1007 (2005).
Casey, M., Ebinger, C., Keir, D., Gloaguen, R. & Mohamed, F. in The Afar Volcanic Province within the East African Rift System (eds Yirgu, G., Ebinger, C. J. & Maguire, P. K. H.) 143–163 (Geological Society Special Publication 259, The Geological Society, London, 2006).
Keranen. K., Klemperer. S. L., Gloaguen. R. & Eagle Working Group. Three-dimensional seismic imaging of a protoridge axis in the Main Ethiopian rift. Geology 32, 949–952 (2004).
Bastow, I., Stuart, G. W., Kendall, J.-M. & Ebinger, C. J. Upper-mantle seismic structure in a region of incipient continental breakup: Northern Ethiopian Rift. Geophys. J. Int. 162, 479–493 (2005).
Corti, G. et al. Analogue modelling of continental extension: A review focused on the relations between the patterns of deformation and the presence of magma. Earth Sci. Rev. 63, 169–247 (2003).
Lemaux, J., Gordon, R. G. & Royer, J.-Y. The location of the Nubia–Somalia boundary along the Southwest Indian Ridge. Geology 30, 339–342 (2002).
Van Wijk, J. Role of weak zone orientation in continental lithosphere extension. Geophys. Res. Lett. 32, L02303 (2005).
Keranen, K. & Klemperer, S. L. Discontinuous and diachronous evolution of the Main Ethiopian Rift: Implications for development of continental rifts. Earth Planet. Sci. Lett. 265, 96–111 (2008).
Withjack, M. O. & Jamison, W. R. Deformation produced by oblique rifting. Tectonophysics 126, 99–124 (1986).
Tron, V. & Brun, J.-P. Experiments on oblique rifting in brittle-ductile systems. Tectonophysics 188, 71–84 (1991).
Garfunkel, Z. & Beyth, M. in The Afar Volcanic Province within the East African Rift System (eds Yirgu, G., Ebinger, C. J. & Maguire, P. K. H.) 23–42 (Geological Society Special Publication 259, The Geological Society, London, 2006).
Forsyth, D. W. Finite extension and low-angle normal faulting. Geology 20, 27–30 (1992).
Kurz, T., Gloaguen, R., Ebinger, C., Casey, M. & Abebe, B. Deformation distribution and type in the Main Ethiopian Rift (MER): A remote sensing study. J. Afr. Earth Sci. 48, 100–114 (2007).
Kidane, T., Platzman, E., Ebinger, C., Abebe, B. & Rochette, P. in The Afar Volcanic Province within the East African Rift System (eds Yirgu, G., Ebinger, C. J. & Maguire, P. K. H.) 165–183 (Geological Society Special Publication 259, The Geological Society, London, 2006).
Acknowledgements
I thank G. Mulugeta for discussions. Research supported by CNR Funds (RSTL no. 105 ‘Evoluzione della parte Nord del rift Afroarabico e distribuzione regionale delle georisorse’).
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Corti, G. Control of rift obliquity on the evolution and segmentation of the main Ethiopian rift. Nature Geosci 1, 258–262 (2008). https://doi.org/10.1038/ngeo160
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DOI: https://doi.org/10.1038/ngeo160
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