Abstract
SEISMIC reflections from magma chambers have been observed along the fast-spreading East Pacific Rise1,2 and the intermediate-spreading Valu Fa Ridge3,4; sub-axial reflections also exist beneath the intermediate-spreading Juan de Fuca Ridge5. But no magma chambers have been identified beneath the slow-spreading Mid-Atlantic Ridge, suggesting that here magma chambers lie unusually deep or are transient features6-11. Seismic reflection profiles acquired in 1989 over the Snake Pit hydrothermal area, in the rift valley of the Mid-Atlantic Ridge ~25 km south of the Kane fracture zone, showed no evidence of magmatic activity12, although geochemical analyses of hydrothermal vent fluids suggest the existence of magma at depths as shallow as 1á¤-2 km13,14. By suppressing in these data high-amplitude coherent noise generated at the sea floor, I have obtained images, in an otherwise non-reflective crust, of seismic reflections beneath, and just south of, the Snake Pit hydrothermal area. These reflections define a small, 4-km-wide dome whose apex is ~ 1,200 m beneath the sea floor. As bright reflections from the upper flanks of this dome occur in the depth range suggested by the vent-fluid geochemistry, I interpret the dome to be the seismic expression of a small magma chamber.
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References
Herron, T. J., Stoffa, P. & Buhl, P. Geophys. Res. Lett. 7, 989–992 (1980).
Detrick, R. S. et al. Nature 326, 35–41 (1987).
Morton, J. L. & Sleep, N. H. Geology and Offshore Resources of Pacific Island Arcs—Tonga Region 441–453 (Circum-Pacific Council for Energy and Mineral Resources, Houston, 1985).
Collier, J. & Sinha, M. Nature 346, 646–648 (1990).
Rohr, K. M. M., Milkereit, B. & Yorath, C. J. Geology 16, 533–537 (1988).
Sleep, N. H. J. geophys. Res. 80, 4037–4042 (1975).
Lilwall, R. C., Francis, T. J. G. & Porter, I. T. Geophys. J. R. astr. Soc. 51, 357–369 (1977).
Fowler, C. M. R. Geophys. J. R. astr. Soc. 54, 167–183 (1978).
Louden, K. E., White, R. S., Potts, C. G. & Forsyth, D. W. J. geol. Soc. Lond. 143, 795–806 (1986).
Purdy, G. M. & Detrick, R. S. J. geophys. Res. 91, 3739–3762 (1986).
Huang, P. Y. & Solomon, S. C. J. geophys. Res. 93, 13445–13477 (1988).
Detrick, R. S., Mutter, J. C., Buhl, P. & Kim, I. Nature 347, 61–64 (1990).
Karson, J. A. et al. Nature 328, 681–685 (1987).
Campbell, A. C. et al. Nature 335, 514–519 (1988).
Melson, W. G., Thompson, G. & van Andel, Tj. H. J. geophys. Res. 73, 5925–5941 (1968).
Karson, J. A. & Dick, H. J. B. Mar. geophys. Res. 6, 51–98 (1983).
Kong, L. S. L., Detrick, R. S., Fox, P. J., Mayer, L. A. & Ryan, W. B. F. Mar. geophys. Res. 10, 59–90 (1988).
Schulz, N. J. R., Detrick, R. S. & Miller, S. P. Mar. geophys. Res. 10, 41–57 (1988).
Morris, E. & Detrick, R. S. J. geophys. Res. 96, 4355–4366 (1991).
Leg 109 Scientific Party Nature 323, 492–493 (1986).
ODP Leg 106 Scientific Party Geology 14, 1004–1007 (1986).
Larner, K., Chambers, R., Yang, M., Lynn, W. & Wai, W. Geophysics 48, 854–886 (1983).
Tsai, C. J. Geophysics 49, 17–26 (1984).
Kim, I. I. & Orcutt, J. A. in Expanded Abstracts, 61st A. Int. Mtg., Soc. expl. Geophys. 1395–1398 (SEG, Tulsa, 1991).
Hale, I. D. Dip-moveout Processing, SEG course notes series Vol. 4 (ed. Domenico, S. N.) (SEG, Tulsa, 1991).
Chambers, R., Jakubowicz, H., Larner, K. & Yang, M. in Expanded Abstracts, 54th A. Int. Mtg., Soc. expl. Geophys. S5.6 (SEG, Tulsa, 1984).
Taner, M. T. & Koehler, F. Geophysics 34, 859–881 (1969).
Brocher, T. M., Karson, J. A. & Collins, J. A. Geology 13, 62–65 (1985).
Cormier, M.-H., Detrick, R. S. & Purdy, G. M. J. geophys. Res. 89, 10249–10266 (1984).
White, R. S. et al. Geology 18, 462–465 (1990).
Srivastava, S. P. & Keen, C. E. Tectonics 14, 372–389 (1995).
Cannat, M. et al. Geology 23, 49–52 (1995).
Avedik, F. & Géli, L. Geology 15, 857–860 (1987).
Hampson, D. in Expanded Abstracts, 56th A. Int. Mtg., Soc. expl. Geophys. 422–424 (SEG, Tulsa, 1986).
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Calvert, A. Seismic evidence for a magma chamber beneath the slow-spreading Mid-Atlantic Ridge. Nature 377, 410–414 (1995). https://doi.org/10.1038/377410a0
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DOI: https://doi.org/10.1038/377410a0
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