Mantle transition zone structure and upper mantle S velocity variations beneath Ethiopia: Evidence for a broad, deep-seated thermal anomaly

Geochemistry, Geophysics, Geosystems

Volumn 7, Issue 11, 2006, Pages

  Benoit, Margaret H ^a,b   Nyblade, Andrew A ^a   Owens, Thomas J ^c   Stuart, Graham ^d  

^a PENNSYLVANIA STATE UNIVERSITY   (United States)

^b MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

^c UNIVERSITY OF SOUTH CAROLINA   (United States)

^d UNIVERSITY OF LEEDS   (United Kingdom)

Author keywords

Afar; Ethiopia; Mantle plume; Superplume

Indexed keywords

EID: 35148832288     PISSN: 15252027     EISSN: 15252027     Source Type: Journal    
DOI: 10.1029/2006GC001398     Document Type: Article

References (57)

1. Ayalew, D., P. Barbey, B. Marty, L. Reisberg, G. Yirgu, and R. Pik (2002), Origin and timing of Ethiopian ignimbrites, Geophys. J., 36, 409-419.
2. Baker, J., L. Snee, and M. Menzies (1996), A brief Oligocene period of flood volcanism in Yemen, Earth Planet. Sci. Lett., 138, 39-55.
3. Bastow, I. D., G. W. Stuart, J.-M. Kendall, and C. J. Ebinger (2005), Upper mantle seismic structure in a region of incipient continental breakup: Northern Ethiopian rift, Geophys. J. Int., 162, 479-493.
4. Benoit, M. H., A. A. Nyblade, and J. C. VanDecar (2006), Upper mantle P wave speed variations beneath Ethiopia and the origin of the Afar Hotspot, Geology, 34, 329-332.
5. Bina, C. R., and G. Helffrich (1994), Phase transition Clapeyron slopes and transition zone seismic discontinuity topography, J. Geophys. Res., 99, 15,853-15,860.
6. Bostock, M. G., and J. C. Vandecar (1995), Upper mantle structure of the northern Cascadia subduction zone, Can. J. Earth. Sci., 32, 1-12.
7. Burke, K. (1996), The African plate, S. Afr. J. Geol., 99, 339-409. (Pubitemid 27457330)
8. Chernet, T., and W. K. Hart (1999), Petrology and geochemistry of volcanism in the northern Main Ethiopian Rift-southern Afar transition region, Acta Vulcanol., 11, 21-41.
9. Chevrot, S., L. Vinnik, and J.-P. Montagner (1999), Globalscale analysis of the mantle Pds phases, J. Geophys. Res., 104, 20,203-20,219.
10. Coulie, E., X. Quidelleur, P. Y. Gillet, V. Courtillot, J. C. Lefevre, and S. Chiesa (2003), Comparative K-Ar and Ar/Ar dating of Ethiopian and Yemenite Oligocene volcanism: Implications for timing and duration of the Ethiopian Traps, Earth Planet. Sci. Lett., 200, 292-477.
11. Courtillot, V. C. J., I. Manighetti, P. Tapponnier, and J. Besse (1999), On casual links between flood basalts and continental breakup, Earth Planet. Sci. Lett., 166, 177-195.
12. Davidson, A., and D. Rex (1980), Age of volcanism and rifting in southwestern Ethiopia, Nature, 283, 657-658. (Pubitemid 10252678)
13. Debayle, E., J. J. Lévêque, and M. Cara (2001), Seismic evidence for a deeply rooted low-velocity anomaly in the upper mantle beneath the northeastern Afro/Arabian continent, Earth Planet. Sci. Lett., 193, 423-436.
14. Dugda, M. T., A. A. Nyblade, J. Julia, C. A. Langston, C. J. Ammon, and S. Simiyu (2005), Crustal structure in Ethiopia and Kenya from receiver function analysis: Implications for rift development in eastern Africa, J. Geophys. Res., 110, B01303, doi:10.1029/2004JB003065. (Pubitemid 40517758)
15. Ebinger, C. J., and N. J. Hayward (1996), Soft plates and hot spots: Views from Afar, J. Geophys. Res., 101, 21,859-21,876.
16. Ebinger, C., and N. Sleep (1998), Cenozoic magmatism throughout east Africa resulting from impact of one large plume, Nature, 395, 788-791.
17. Ebinger, C. J., T. Yemane, G. WoldeGabriel, J. L. Aronson, and R. C. Walter (1993), Late Eocene-recent volcanism and faulting in the southern main Ethiopian Rift, J. Geol. Soc. London, 150, 99-108.
18. Ebinger, C., T. Yemane, D. Harding, S. Tesfaye, D. Rex, and S. Kelley (2000), Rift deflection, migration, and propagation: Linkage of the Ethiopian and Eastern rifts, Africa, Geol. Soc. Am. Bull., 102, 163-176.
19. Faul, U. H., and I. Jackson (2005), The seismological signature of temperature and grain size variations in the upper mantle, Earth Planet. Sci. Lett., 234, 119-134.
20. Gashawbeza, E. M., S. L. Klemperer, A. A. Nyblade, K. T. Walker, and K. M. Keranen (2004), Shear-wave splitting in Ethiopia: Precambrian mantle anisotropy locally modified by Neogene rifting, Geophys. Res. Lett., 31, L18602, doi:10.1029/2004GL020471. (Pubitemid 39660808)
21. Gasparik, T. (1993), The role of volatiles in the transition zone, J. Geophys. Res., 98, 4287-4299.
22. George, R., N. Rogers, and S. Kelley (1998), Earliest magmatism in Ethiopia: Evidence for two mantle plumes in one flood basalt province, Geology, 26, 923-926.
23. Grand, S. P. (2002), Mantle shear wave tomography and the fate of subducted slabs, Philos. Trans. R. Soc. London, Ser. A, 360, 2475-2491.
24. Grand, S. P., R. D. van der Hilst, and S. Widiyantoro (1997), Global seismic tomography: A snapshot of convection in the Earth, GSA Today, 7(4), 1-7. (Pubitemid 27472170)
25. Griffiths, R. W., and I. H. Campbell (1990), Stirring and structure in mantle starting plumes, Earth Planet. Sci. Lett., 99, 66-78.
26. Kendall, J.-M., G. W. Stuart, C. J. Ebinger, I. D. Bastow, and D. Keir (2005), Magma-assisted rifting in Ethiopia, Nature, 433, 146-148.
27. Kennett, B. N. L., and E. R. Engdahl (1991), Travel times for global earthquake location and phase identification, Geophys. J. Int., 105, 429-465.
28. Kieffer, B., et al. (2004), Flood and shield basalts from Ethiopia: Magmas from the African Superswell, J. Petrol., 45, 793-834.
29. Langston, C. A. (1979), Structure under Mount Rainier, Washington, inferred from teleseismic body waves, J. Geophys. Res., 84, 4749-4762.
30. Li, X.-D., and B. Romanowicz (1996), Global mantle shear velocity model developed using nonlinear asymptotic coupling theory, J. Geophys. Res., 101, 22,245-22,272.
31. Ligorria, J., and C. J. Ammon (1999), Iterative deconvolution of teleseismic seismograms and receiver functions estimation, Bull. Seismol. Soc. Am., 89, 1395-1400.
32. Maguire, P. K. H., et al. (2003), Geophysical project in Ethiopia studies continental breakup, Eos Trans. AGU, 84(35), 337, 342-343.
33. Marty, B., R. Pik, and Y. Gezahagen (1996), Helium isotopic variations in the Ethiopia plume lavas: Nature of magmatic sources and limit on lower mantle contribution, Earth Planet. Sci. Lett., 144, 223-237.
34. Masters, G., S. Johnson, G. Laske, and H. Bolton (1996), A shear-velocity model of the mantle, Phil. Trans. R. Soc. London, Ser. A, 354, 1385-1411.
35. Mohr, P. (1983), Ethiopian flood basalt province, Nature, 303, 577-583.
36. Montelli, R., G. Nolet, F. A. Dahlen, G. Masters, E. R. Engdahl, and S.-H. Hung (2004), Finite-frequency tomography reveals a variety of plumes in the mantle, Science, 303, 338-343.
37. Niu, F., and H. Kawakatsu (1996), Complex structure of the mantle discontinuities at the tip of the subducting slab beneath the Northeast China: A preliminary investigation of broadband receiver functions, J. Phys. Earth, 44, 701-711.
38. Nyblade, A. A., and C. A. Langston (2002), Broadband seismic experiments probe the East African Rift, Eos Trans. AGU, 83(37), 405-408.
39. Nyblade, A. A., R. P. Knox, and H. Gurrola (2000), Mantle transition zone thickness beneath Afar: Implications for the origin of the Afar hotspot, Geophys. J. Int., 142, 615-619.
40. Owens, T. J., A. A. Nyblade, H. Gurrola, and C. A. Langston (2000), Mantle transition zone structure beneath Tanzania, East Africa, Geophys. Res. Lett., 27, 827-830.
41. Pik, R., B. Marty, J. Carignan, and J. Lave (2003), Stability of the upper Nile drainage network (Ethiopia) deduced from (U-Th)/He thermochronometry: Implications for uplift and erosion of the Afar Plume dome, Earth Planet. Sci. Lett., 215, 73-88.
42. Pik, R., B. Marty, and D. R. Hilton (2006), How many mantle plumes in Africa? The geochemical point of view, Chem. Geol., 226, 100-114.
43. Rigden, S. M., G. D. Gwanmesia, J. D. FitzGerald, I. Jackson, and R. C. Liebermann (1991), Spinel elasticity and seismic structure of the transition zone of the mantle, Nature, 354, 143-145.
44. Ritsema, J., A. A. Nyblade, T. J. Owens, C. L. Langston, and J. C. VanDecar (1998), Upper mantle seismic velocity structure beneath Tanzania, east Africa: Implications for the stability of cratonic lithosphere, J. Geophys. Res., 103, 21,201-21,213.
45. Ritsema, J., H. J. van Heijst, and J. H. Woodhouse (1999), Complex shear wave velocity structure beneath Africa and Iceland, Science, 286, 1925-1928.
46. Rondenay, S., M. G. Bostock, and K. M. Fischer (2005), Multichannel inversion of scattered teleseismic body waves: Practical considerations and applicability, in Seismic Earth: Array Analysis of Broadband Seismograms, Geophys. Monogr. Ser., vol.157, edited by A. Levander and G. Nolet, pp. 187-204, AGU, Washington, D. C.
47. Schilling, J.-G., R. Kingsley, B. Hanan, and B. McCully (1992), Nd-Sr-Pb isotopic variations along the Gulf of Aden: Evidence for the Afar mantle plume-lithosphere interaction, J. Geophys. Res., 97, 10,927-10,966.
48. Simmons, N. A., and H. Gurrola (2000), Mantle seismic discontinuities near the base of the transition zone in the Earth's mantle, Nature, 405, 559-562.
49. Su, W., R. L. Woodward, and A. M. Dziewonski (1994), Degree 12 model of shear velocity heterogeneity in the mantle, J. Geophys. Res., 99, 6945-6981.
50. Trampert, J., F. Deschamps, J. Resovsky, and D. Yuen (2004), Probabilistic tomography maps chemical heterogeneities throughout the lower mantle, Science, 306, 853-856.
51. VanDecar, J. C. (1991), Upper-mantle structure of the Cascadia subduction zone from nonlinear teleseismic travel-time inversion, Ph.D. thesis, Univ. of Wash., Seattle.
52. VanDecar, J. C., and R. S. Crosson (1990), Determination of teleseismic relative phase arrival times using multi-channel cross-correlation and least squares, Bull. Seismol. Soc. Am., 80, 150-169.
53. Van der Lee, S., H. Paulssen, and G. Nolet (1994), Variability of P660s phases as a consequence of topography of the 660 km discontinuity, Phys. Earth Planet. Inter., 86, 147-164.
54. WoldeGabriel, G., J. Aronson, and R. Walter (1990), Tectonic development of the Main Ethiopian rift, Geol. Soc. Am. Bull, 102, 439-458.
55. WoldeGabriel, G., R. C. Walter, W. K. Hart, S. A. Mertzman, and J. L. Aronson (1997), Temporal relations and geochemical features of felsic volcanism in the central sector of the Main Ethiopian Rift, Acta Vulcanol., 11, 53-67.
56. Wolfenden, E., C. Ebinger, G. Yirgu, A. Deino, and D. Ayalew (2004), Evolution of the northern main Ethiopian rift: Birth of a triple junction, Earth. Planet. Sci. Lett., 224, 213-228.
57. Zanettin, B., E. Justin-Visentin, M. Nicoletti, and E. M. Piccirillo (1980), Correlations among Ethiopian volcanic formations with special references to the chronological and stratigraphic problems of the trap series, Rome, Italy, Accad. Naz. Lincei, 47, 231-252.