Skip to main content
SpringerLink
Log in

Segmentation and morphotectonic variations along a slow-spreading center: The Mid-Atlantic Ridge (24°00′ N– 30°40′ N)

  • Published:
Marine Geophysical Researches Aims and scope Submit manuscript

Abstract

Analysis of Sea Beam bathymetry along the Mid-Atlantic Ridge between 24°00′ N and 30°40′ N reveals the nature and scale of the segmentation of this slow-spreading center. Except for the Atlantis Transform, there are no transform offsets along this 800-km-long portion of the plate boundary. Instead, the Mid-Atlantic Ridge is offset at intervals of 10–100 km by nontransform discontinuities, usually located at local depth maxima along the rift valley. At these discontinuities, the horizontal shear between offset ridge segments is not accommodated by a narrow, sustained transform-zone. Non-transform discontinuities along the MAR can be classified according to their morphology, which is partly controlled by the distance between the offset neovolcanic zones, and their spatial and temporal stability. Some of the non-transform discontinuities are associated with off-axis basins which integrate spatially to form discordant zones on the flanks of the spreading center. These basins may be the fossil equivalents of the terminal lows which flank the neovolcanic zone at the ends of each segment. The off-axis traces, which do not lie along small circles about the pole of opening of the two plates, reflect the migration of the discontinuities along the spreading center.

The spectrum of rift valley morphologies ranges from a narrow, deep, hourglass-shaped valley to a wide valley bounded by low-relief rift mountains. A simple classification of segment morphology involves two types of segments. Long and narrow segments are found preferentially on top of the long-wavelength, along-axis bathymetric high between the Kane and Atlantis Transforms. These segments are associated with circular mantle Bouguer anomalies which are consistent with focused mantle upwelling beneath the segment mid-points. Wide, U-shaped segments in cross-section are preferentially found in the deep part of the long-wavelength, along-axis depth profile. These segments do not appear to be associated with circular mantle Bouguer anomalies, indicating perhaps a more complex pattern of mantle upwelling and/or crustal structure. Thus, the long-recognized bimodal distribution of segment morphology may be associated with different patterns of mantle upwelling and/or crustal structure. We propose that the range of observed, first-order variations in segment morphology reflects differences in the flow pattern, volume and temporal continuity of magmatic upwelling at the segment scale. However, despite large first-order differences, all segments display similar intra-segment, morphotectonic variations. We postulate that the intra-segment variability represents differences in the relative importance of volcanism and tectonism along strike away from a zone of enhanced magma upwelling within each segment. The contribution of volcanism to the morphology will be more important near the shallowest portion of the rift valley within each segment, beneath which we postulate that upwelling of magma is enhanced, than beneath the ends of the segment. Conversely, the contribution of tectonic extension to the morphology will become more important toward the spreading center discontinuities. Variations in magmatic budget along the strike of a segment will result in along-axis variations in crustal structure. Segment mid-points may coincide with regions of highest melt production and thick crust, and non-transform discontinuities with regions of lowest melt production and thin crust. This hypothesis is consistent with available seismic and gravity data.

The rift valley of the Mid-Atlantic Ridge is in general an asymmetric feature. Near segment mid-points, the rift valley is usually symmetric but, away from the segment mid-points, one side of the rift valley often consists of a steep, faulted slope while the other side forms a more gradual ramp. These observations suggest that half-grabens, rather than full-grabens, are the fundamental building blocks of the rift valley. They also indicate that the pattern of faulting varies along strike at the segment scale, and may be a consequence of the three-dimensional, thermo-mechanical structure of segments associated with enhanced mantle upwelling beneath their mid-points.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Argus, D. F., Gordon, R. G., DeMets, C., and Stein, S., 1989, Closure of the Africa-Eurasia-North-America plate motion circuit and tectonics of the Gloria fault,J. Geophys. Res. 94, 5585–5603.

    Google Scholar 

  • Ballard, R. D. and T. H. van Andel, 1977, Morphology and tectonics of the inner rift valley at lat 36°50′ N on the Mid-Atlantic Ridge,Geol. Soc. Am. Bull. 88, 507–530.

    Google Scholar 

  • Barone, A. M. and Ryan, W. B. F., 1988, Along-axis variations within the plate boundary zone of the Southern segment of the Endeavour Ridge,J. Geophys. Res. 93, 7856–7868.

    Google Scholar 

  • Bergman, E. A. and Solomon, S. C., 1990, Earthquake swarms on the Mid-Atlantic Ridge: Products of magmatism or extensional tectonics?J. Geophys. Res. 95, 4943–4965.

    Google Scholar 

  • Bosworth, W., 1985, Geometry of propagating continental rifts,Nature 316, 625–627.

    Google Scholar 

  • Brown, J. R. and Karson, J. A., 1988, Variations in axial processes on the Mid-Atlantic Ridge: The median valley of the MARK area,10, 109–138.

  • Brown, H. S., Sempéré, J.-C., Rommevaux, C., and Patriat, P., 1990, Three-Dimensional Inversion of the Magnetic Field along the Mid-Atlantic Ridge: Evolution of the Plate Boundary between 28° N and 29° N in the last 10 Ma (abstract),EOS Trans AGU 71, 1572.

    Google Scholar 

  • Brozena, J., 1986, Temporal and spatial variability of seafloor spreading processes in the northern South Atlantic,J. Geophys. Res. 91, 497–510.

    Google Scholar 

  • Brozena, J. and Chayes, D., 1988, A sea Beam study of the Mid-Atlantic Ridge, 15°–17° S (abstract),Eos Trans. AGU 69, 1494.

    Google Scholar 

  • Carbotte, S., Welch, S. M., and Macdonald, K. C., 1991, Spreading rates, rift propagation, and fracture zones offset histories during the past 5 My on the Mid-Atlantic Ridge; 25°–27°30′ S and 31°–34°30′ S,Mar. Geophys. Res. 13, 51–80.

    Google Scholar 

  • Choukroune, P., Francheteau, J., and LePichon, X., 1978, In situ structural observations along Transform Fault A in the FAMOUS area,Bull. Geol. Soc. Am. 88, 1013–1029.

    Google Scholar 

  • Cormier, H. H., Detrick, R. S., and Purdy, G. M., 1984, Anomalously thin crust in oceanic fracture zones: New seismic constraints from the Kane fracture zone,J. Geophys. Res. 89, 10249–10266.

    Google Scholar 

  • Crane, K. and Ballard, R. D., 1981, Volcanics and structure of the FAMOUS Narrowgate rift: Evidence for cyclic evolution,J. Geophys. Res. 86, 5112–5124.

    Google Scholar 

  • Crane, K., 1985, The spacing of rift axis highs: Dependence upon diapiric processes in the underlying asthenosphere?Earth Planet, Sci. Lett. 72, 405–414.

    Google Scholar 

  • Detrick, R. S., Mudie, J. D., Luyendyk, B. P., and Macdonald, K. C., 1973, Near-bottom observations of an active transform fault (Mid-Atlantic Ridge at 37° N),Nature 246, 59–61.

    Google Scholar 

  • Detrick, R. S., Cormier, M. H., Prince, R. A., Forsyth, D. W., and Ambos, E. L., 1982, Seismic constraints on the crustal structure of the Vema fracture zone,J. Geophys. Res. 87, 10599–10612.

    Google Scholar 

  • Dick, H. J. B., 1989, Abyssal peridotites, very slow spreading ridges and ocean ridge magmatism, In A. D. Saunders and M. J. Norry (eds.), Magmatism in the Ocean BasinsGeological Society Special Publication 42, 71–105.

    Google Scholar 

  • Eberhart, G. L., Rona, P. A., and Honnorez, J., 1988, Geologic controls of hydrothermal activity in the Mid-Atlantic Ridge rift valley: Tectonics and volcanics,Mar. Geophys. Res. 10, 233–259.

    Google Scholar 

  • Ebinger, C. J., 1989a, Tectonic development of the western branch of the East African rift system,Geol. Soc. Am. Bull. 101, 885–903.

    Google Scholar 

  • Ebinger, C. J., 1989b, Geometric and kinematic development of border faults and accommodation zones, Kivu-Rusizi rift, Africa,Tectonics 8, 117–133.

    Google Scholar 

  • Ebinger, C. J., Deino, A. L., Drake, R. E., and Teisha, A. L., 1989, Chronology of volcanism and rift basin propagation: Rungwe volcanic province, East Africa,J. Geophys. Res. 94, 15785–15803.

    Google Scholar 

  • Fox, P. J. and Gallo, D. G., 1984, A tectonic model for ridge-trans-form-ridge plate tectonics: Implications for the structure of oceanic lithosphere,Tectonophysics 104, 205–242.

    Google Scholar 

  • Fox, P. J., Grindlay, N. R., Macdonald, K. C., Bicknell, J. D., and Forsyth, D. W., 1985, The morphotectonic character of the Mid-Atlantic Ridge between 31–34° S: Implications for plate accretion (abstract),Eos Trans. AGU 66, 1078.

    Google Scholar 

  • Fox, P. J. and Gallo, D. G., 1986, The geology of north Atlantic transform plate boundaries and their aseismic extensions, In P. Vogt and B. Tucholke (eds.), Decade of North American Geology, vol. M, Geological Society of America, Boulder, Colo., pp. 157–172.

    Google Scholar 

  • Fox, P. J., Grindlay, N. R., and Macdonald, K. C., 1991, The Mid-Atlantic Ridge (31°–34° S): Temporal and spatial variations of accretionary processes,Mar. Geophys. Res. 13, 1–20.

    Google Scholar 

  • Gente, P., Aslanian, D., Campan, A., Cannat, M., Ceuleneer, G., Deplus, C., Durand, C., Laverne, C., Leau, H., Maia, M., Marion, E., Mével, C., Pockalny, R., and Seyler, M., 1991, Geometry of past and present-day segmentation of the Mid-Atlantic Ridge south of Kane fracture zone (abstract),EOS Trans. AGU 72, 476–477.

    Google Scholar 

  • Gibbs, A. D., 1984, Structural evolution of extensional basin margins,J. Geol. Soc. Lond. 141, 609–620.

    Google Scholar 

  • Glenn, M. F., 1976, Multi-narrow beam sonar systems, Proc. MTS-IEEE Oceans '76 Conf.,8, D1-D2.

    Google Scholar 

  • Goud, M. R. and Karson, J. A., 1985, Tectonics of short-offset, slow-slipping transform zones in the FAMOUS area, Mid-Atlantic Ridge,Mar. Geophys. Res. 7, 489–514.

    Google Scholar 

  • Grindlay, N. R., Fox, P. J., and Macdonald, K. C., 1991, Second-order ridge axis discontinuities in the south Atlantic: Morphology, structure, and evolution,Mar. Geophys. Res. 13, 21–50.

    Google Scholar 

  • Harper, G. D., 1988, Episodic magma chambers and amagmatic extension in the Josephine ophiolite,Geology 16, 831–834.

    Google Scholar 

  • Johnson, G. L. and Vogt, P. R., 1973, Mid-Atlantic Ridge from 47° to 51° N,Geol. Soc. Am. Bull. 84, 3443–3462.

    Google Scholar 

  • Kappel, E. S. and Ryan, W. B. F., 1986, Volcanic episodicity and a non-steady state rift valley along northeast Pacific spreading centers: Evidence from SeaMARC I,J. Geophys. Res. 91, 13925–13940.

    Google Scholar 

  • Karson, J. A. and Dick, H. J. B., 1983, Tectonics of ridge transform intersections at the Kane fracture zone,Mar. Geophys. Res. 6, 51–98.

    Google Scholar 

  • Karson, J. A., Thompson, G., Humphris, S. E., Edmond, J. M., Bryan, W. B., Brown, J. R., Winters, A. T., Pockalny, R. A., Casey, J. R., Campbell, A. C., Klinkhammer, G., Palmer, M., Kinzler, R. J., and Sulanowska, M. M., 1987, Along-axis variations in seafloor spreading in the MARK area,Nature 328, 681–685.

    Google Scholar 

  • Karson, J. A. and Curtis, P. C., 1989, Tectonic and magmatic processes in the Eastern Branch of the East African Rift and implications for magmatically active continental rifts,J. of African Earth Sciences 8, 431–453.

    Google Scholar 

  • Karson, J. A. and Rona, P. A., 1990, Block-tilting, transfer faults and structural control on magmatic activity and hydrothermal processes in the TAG area, Mid-Atlantic Ridge 26° N,Geol. Soc. Am. Bull. 102, 1635–1645.

    Google Scholar 

  • Karson, J. A., 1990, Accommodation zones and transfer faults: Integral components of Mid-Atlantic Ridge extensional systems, In A. Nicolas and Tj. Peters (eds.),Proceedings of the Symposium on Oceanic Lithosphere and the Oman Ophiolite, in press.

  • Kong, L. S. L., Detrick, R. S., Fox, P. J., Mayer, L. A., and Ryan, W. B. F., 1988, The morphology and tectonics of the MARK area from Sea Beam and Sea MARC I observations (Mid-Atlantic Ridge 23° N),Mar. Geophys. Res. 10, 59–90.

    Google Scholar 

  • Kong, L. S. L., Solomon, S. C., and Purdy, G. M., 1992, Microearthquake characteristics of a mid-ocean ridge alongaxis high,J. Geophys. Res. 97, 1659–1685.

    Google Scholar 

  • Kong, L. S. L., Purdy, G. M., and Solomon, S. C., 1991b, Along-axis variations in crustal structure on the Mid-Atlantic Ridge near 26° N,J. Geophys. Res., (submitted).

  • Langmuir, C. H., Bender, J. F., and Batiza, R., 1986, Petrologic and tectonic segmentation of the East Pacific Rise, 5°30′ N–14°30′ N,Nature 322, 422–429.

    Google Scholar 

  • LeDouaran, S. and Francheteau, J., 1981, Axial depth anomalies from 10 to 50° north along the Mid-Atlantic Ridge: correlation with other mantle properties,Earth Planet. Sci. Lett. 54, 29–47.

    Google Scholar 

  • Lin, J., Purdy, G. M., Schouten, H., Sempéré, J.-C., and Zervas, C., 1990, Evidence from gravity data for focused magmatic accretion along the Mid-Atlantic Ridge,Nature 344, 627–632.

    Google Scholar 

  • Lin, J. and Bergman, E. A., 1991, Rift grabens, seismicity, and volcanic segmentation of the Mid-Atlantic Ridge: Kane to Atlantis Fracture Zones (abstract),EOS Trans. AGU 71, 1572.

    Google Scholar 

  • Lin, J. and Phipps Morgan, J., 1992, The spreading rate dependence of 3-D Mid-ocean ridge structure,Geophys. Res. Lett. 19, 13–16.

    Google Scholar 

  • Lonsdale, P., 1983, Overlapping rift zones at the 5.5° S offset of the East Pacific Rise,J. Geophys. Res. 88, 9393–9406.

    Google Scholar 

  • Lonsdale, P., 1985, Non transform offsets of the Pacific-Cocos plate boundary and their trace on the rise flank,Geol. Soc. Am. Bull. 96, 313–327.

    Google Scholar 

  • Lonsdale, P., 1989, The rise flank trails left by migrating offsets of the equatorial East Pacific Rise axis,J. Geophys. Res. 94, 713–743.

    Google Scholar 

  • Lonsdale, P., 1989b, Segmentation of the Pacific-Nazca spreading center, 1° N–20° S,J. Geophys. Res. 94, 12197–12225.

    Google Scholar 

  • Louden, K. E. and Forsyth, D. W., 1982, Crustal structure and isostatic compensation near the Kane fracture zone from topography and gravity measurements-I. Spectral analysis approach,Geophys. J. R. Astr. Soc. 68, 725–750.

    Google Scholar 

  • Luyendyk, B. P. and Macdonald, K. C., 1977, Physiography and structure of the inner floor of the FAMOUS rift valley: observations with a deeply towed instrument package,Geol. Soc. Am. Bull. 88, 648–663.

    Google Scholar 

  • Macdonald, K. C. and Luyendyk, B. P., 1977, Deep-tow studies of the structure of the Mid-Atlantic Ridge crest near lat. 37° N,Geol. Soc. Am. Bull. 88, 621–636.

    Google Scholar 

  • Macdonald, K. C., Sempéré, J.-C., and Fox, P. J., 1984, The East Pacific Rise from the Siqueiros to the Orozco fracture zone: Along strike continuity of the neovolcanic zone and the structure and evolution of overlapping spreading centers,J. Geophys. Res. 89, 6049–6069.

    Google Scholar 

  • Macdonald, K. C., Sempéré, J.-C., and Fox, P. J., 1986, Reply: The debate concerning overlapping spreading centers and midocean ridge processes,J. Geophys. Res. 91, 10501–10511.

    Google Scholar 

  • Macdonald, K. C., 1986, The crest of the Mid-Atlantic Ridge: Models for crustal generation processes and tectonics, In P. Vogt and B. Tucholke (eds.),Decade of North American Geology: The Western North Atlantic Region, vol. M., Geological Society of America, Boulder, Colo., pp. 51–68.

    Google Scholar 

  • Macdonald, K. C., Fox, P. J., Perram, L. J., Eisen, M. F., Haymon, R. M., Miller, S. P., Carbotte, S. M., Cormier, M.-H., and Shor, A. N., 1988, A new view of the mid-ocean ridge from the behaviour of the ridge axis-discontinuities,335, 217–225.

  • McCarthy, J., Mutter, J. C., Morton, J. L., Sleep, N. H., and Thompson, G. A., 1988, Relic magma chamber structures preserved within the Mesozoic North Atlantic crust?Geol. Soc. Am. Bull. 100, 1423–1436.

    Google Scholar 

  • Melson, W. G. and O'Hearn, T., 1986, ‘Zero-age’ variations in the composition of abyssal volcanic rocks along the axial zone of the Mid-Atlantic Ridge, In P. Vogt and B. Tucholke (eds.),Decade of North American Geology: The western north Atlantic Region, Vol. M., Geological Society of America, Boulder, Colo., pp. 117–136.

    Google Scholar 

  • Miller, S. P., 1977, The validity of the geological interpretation of marine magnetic anomalies,Geophys. J. R. Astron. Soc. 50, 1–21.

    Google Scholar 

  • Minshull, T. A., White, R. S., Mutter, J. C., Buhl, P., Detrick, R. S., Williams, C. A., and Morris, E., 1991, Crustal structure at the Blake Spur Fracture Zone from expanding spread profiles,J. Geophys. Res. 96, 9955–9984.

    Google Scholar 

  • Morley, C. K., Nelson, R. A., Patton, T. L., and Munn, S. G., 1990, Transfer zones in the East African Rift system and their relevance to hydrocarbon exploration in rifts,Am. Ass. Petrol. Geol. 74, 1234–1253.

    Google Scholar 

  • Morris, E. and Detrick, R. S., 1991, Three-dimensional analysis of gravity anomalies in the MARK area, Mid-Atlantic Ridge 23° N,J. Geophys. Res. 96, 4355–4366.

    Google Scholar 

  • Mutter, J. C., Detrick, R. S., and the NAT Study Group, 1984, Multichannel seismic evidence for anomalously thin crust at Blake-Spur fracture zone,Geology 12, 534–537.

    Google Scholar 

  • Mutter, J. C. and North Atlantic Transect Study Group, 1985, Multichannel seismic images of the oceanic crust's internal structure: Evidence for a magma chamber beneath the Mesozoic Mid-Atlantic Ridge,Geology 13, 629–632.

    Google Scholar 

  • Needham, H. D., Auffret, G. A., Ballu, V., Beuzart, P., Dauteuil, O., Detrick, R., Dubois, J., Carré, D., Lance, S., Langmuir, C., LeDrezen, E., Normand, A., Renard, V., Voisset, M., and Bougault, H., 1991, The crest of the Mid-Atlantic Ridge between 40° N and 15° N: Very broad swath mapping with the EM12 echosounding system (abstract),EOS Trans. AGU 72, 470.

    Google Scholar 

  • Nicolas, A., 1985, Novel type of oceanic crust produced during continental rifting,Nature 315, 112–115.

    Google Scholar 

  • North Atlantic Transect Study Group, 1985, North Atlantic Transect: A wide-aperture, two-ship multichannel seismic investigation of the oceanic crust,J. Geophys. Res. 90, 10321–10341.

    Google Scholar 

  • Norrell, G. T. and Harper, G. D., 1988, Detachment faulting and amagmatic extension at mid-ocean ridges: the Josephine ophiolite as an example,Geology 16, 827–830.

    Google Scholar 

  • Parmentier, E. M. and Forsyth, D. W., 1985, Three-dimensional flow beneath a slow spreading ridge axis: A dynamic contribution to the deepening of the median valley toward fracture zones,J. Geophys. Res. 90, 678–684.

    Google Scholar 

  • Parmentier, E. M. and Phipps Morgan, J., 1990, The spreading rate dependence of three-dimensional spreading center structure,Nature 348, 325–328.

    Google Scholar 

  • Patriat, P., Deplus, C., Rommevaux, C., Sloan, H., Hunter, P., and Brown, H. S., 1990, Evolution of the segmentation of the Mid-Atlantic Ridge between 28° N and 29° N in the last 10 Ma: Preliminary results from the SARA cruise (R/V Jean Charcot, May 1990) (abstract),EOS Trans AGU 71, 1629.

    Google Scholar 

  • Phillips, J. D. and Fleming, H. S., 1977, Multibeam sonar study of the Mid-Atlantic Ridge rift valley 36°–37° N,Geol. Soc. Am. Bull. 88, 1–5.

    Google Scholar 

  • Phipps Morgan, J., Parmentier, E. M., and Lin, J., 1987, Mechanisms for the origin of mid-ocean ridge axial topography: Implications for the thermal and mechanical structure of accreting plate boundaries,J. Geophys. Res. 92, 12823–12836.

    Google Scholar 

  • Pockalny, R. A., Detrick, R. S., and Fox, P. J., 1988, Morphology and tectonics of the Kane transform from Sea Beam bathymetry data,J. Geophys. Res. 93, 3179–3193.

    Google Scholar 

  • Pollard, D. D. and Aydin, A., 1984, Propagation and linkage of oceanic ridge segments,J. Geophys. Res. 89, 10017–10028.

    Google Scholar 

  • Prévot, M., Lecaille, A., and Hékinian, R., 1979, Magnetism of the Mid-Atlantic Ridge crest near 37° N from FAMOUS and DSDP results: A review, In M. Talwani, C. G. Harrison, and D. E. Hayes (eds.),Deep Sea Drilling Results in the Atlantic Ocean, Maurice Ewing Series 2, AGU, Washington D.C., pp. 431.

    Google Scholar 

  • Prince, R. A. and Forsyth, D. W., 1988, Horizontal extent of anomalously thin crust near the Vema fracture zone from the three-dimensional analysis of gravity anomalies,J. Geophys. Res. 93, 8051–8063.

    Google Scholar 

  • Purdy, G. M. and Detrick, R. S., 1986, The crustal structure of the Mid-Atlantic Ridge at 23° N from seismic refraction studies,J. Geophys. Res. 91, 3739–3762.

    Google Scholar 

  • Purdy, G. M., Sempéré, J.-C., Schouten, H., Dubois, D., and Goldsmith, R., 1990, Bathymetry of the Mid-Atlantic Ridge, 24°–31° N: A Map Series,Mar. Geophys. Res. 12, 247–252.

    Google Scholar 

  • Rabinowicz, M., Phipps Morgan, J., Ceuleneer, G., and Rosenberg, C., 1990, The interaction of small scale convection with 3-D upwelling beneath a spreading center (abstract),EOS Trans. AGU 71, 1637.

    Google Scholar 

  • Ramberg, I. B., Gray, D. F., and Raynolds, R. G. H., 1977, Tectonic evolution of the FAMOUS area of the Mid-Atlantic Ridge, lat. 35°50′ N to 37°20′ N,Geol. Soc. Am. Bull. 88, 609–620.

    Google Scholar 

  • Ramberg, I. B. and van Andel, T. H., 1977, Morphology and tectonic evolution of the rift valley at lat 36°30′ N, Mid-Atlantic Ridge,Geol. Soc. Am. Bull. 88, 577–586.

    Google Scholar 

  • Reid, I. and Macdonald, K. C., 1973, Microearthquake study of the Mid-Atlantic Ridge near 37° N using sonobuoys,Nature 246, 88–90.

    Google Scholar 

  • Renard, V. and Allenou, J. P., 1979, Sea Beam, multibeam echo-sounding in ‘Jean Charcot’,Int. Hydrogr. Rev. 56, 35–67.

    Google Scholar 

  • Rona, P. A., 1976, Asymmetric fracture zones and seafloor spreading,Earth Planet. Sci. Lett. 30, 109–116.

    Google Scholar 

  • Rona, P. A., Harbison, R. N., Bussinger, B. G., Scott, R. B., and Natwalk, A. J., 1976, Tectonic fabric and hydrothermal activity of the Mid-Atlantic Ridge crest (lat 26° N),Geol. Soc. Am. Bull. 87, 661–674.

    Google Scholar 

  • Rona, P. A. and Gray, D. F., 1980, Structural behavior of fracture zones symmetric and asymmetric about a spreading axis: Mid-Atlantic Ridge crest (lat 23° N to 27° N),Geol. Soc. Am. Bull. 91, 485–496.

    Google Scholar 

  • Rona, P. A., Klinkhammer, G., Nelsen, T. A., Trefry, J. H., and Elderfield, H., 1986, Black smoker, massive sulfides and vent biota at the Mid-Atlantic Ridge,Nature 321, 33–37.

    Google Scholar 

  • Rosendahl, B. R., 1987, Architecture of continental rifts with special reference to East Africa,Ann. Rev. Earth Planet. Sci. 15, 445–503.

    Google Scholar 

  • Schilling, J.-G., 1986, Geochemical and isotopic variation along the Mid-Atlantic Ridge axis from 79° N to 0° N, In P. Vogt and B. Tucholke (eds.),Decade of North American Geology: The Western North Atlantic Region, Vol. M., Geological Society of America, Boulder, Colo., pp. 137–156.

    Google Scholar 

  • Schouten, H. and White, R. S., 1980, Zero-offset fracture zones,Geology 8, 175–179.

    Google Scholar 

  • Schouten, H. and Klitgord, D. K., 1982, The memory of the accreting plate boundary and the continuity of fracture zones,Earth Planet. Sci. Lett. 59, 255–266.

    Google Scholar 

  • Schouten, H., Klitgord, K. D., and Whitehead, J. A., 1985, Segmentation of mid-ocean ridges,Nature 317, 225–229.

    Google Scholar 

  • Schouten, H., Dick, H. J. B., and Klitgord, K. D., 1987, Migration of mid-ocean ridges,Nature 326, 835–839.

    Google Scholar 

  • Searle, R. C. and Laughton, A. S., 1977, Sonar studies of the Mid-Atlantic Ridge and Kurchatov Fracture Zone,J. Geophys. Res. 82, 5313–5328.

    Google Scholar 

  • Searle, R. C., 1986, GLORIA investigations of oceanic fracture zones: comparative study of the transform fault zones,J. Geol. Soc. Lond. 143, 743–756.

    Google Scholar 

  • Sempéré, J.-C. and Macdonald, K. C., 1986, Overlapping spreading centers: Implications from crack growth simulation by the displacement discontinuity method,Tectonics 5, 151–163.

    Google Scholar 

  • Sempéré, J.-C., Purdy, G. M., and Schouten, H., 1990, The segmentation of the Mid-Atlantic Ridge between 24° N and 30°40′ N,Nature 344, 427–431.

    Google Scholar 

  • Sempéré, J.-C., 1991, Tectonic variations along the axis of the Mid-Atlantic Ridge: Observations and finite-element modelling (abstract),EOS Trans. AGU 72, 471.

    Google Scholar 

  • Sinha, M. C. and Louden, K. E., 1983, The Oceanographer fracture zone — I. Crustal structure from seismic refraction studies,Geophys. J. R. Astr. Soc. 75, 713–736.

    Google Scholar 

  • Tamsett, D. and Searle, R., 1988, Structure and development of the mid-ocean ridge plate boundary in the Gulf of Aden: Evidence from GLORIA side-scan sonar,J. Geophys. Res. 93, 3157–3178.

    Google Scholar 

  • Tucholke, B. E. and Schouten, H., 1989, Kane Fracture Zone,Mar. Geophys. Res. 10, 1–40.

    Google Scholar 

  • Tucholke, B. E., 1992, Massive submarine rock slide on the rift valley of the Mid-Atlantic Ridge,Geology 20, 129–132.

    Google Scholar 

  • Tyce, R. C., 1986, Deep seafloor mapping systems — A review,MTS Journal 20, 4–16.

    Google Scholar 

  • Vogt, P. R., Cande, S., Fox, P. J., and Grindlay, N. R., 1987, Detailed investigation of a flowline corridor in the south Atlantic: Part I — Mid-Atlantic Ridge crestal area (abstract),Eos Trans. AGU 68, 1491.

    Google Scholar 

  • White, R. S. and Matthews, D. R., 1980, Variations in oceanic upper crustal structure in a small area of the northeastern Atlantic,Geophys. J. Roy. Astr. Soc. 61, 401–431.

    Google Scholar 

  • White, R. S., 1984, Atlantic oceanic crust: seismic structure of a slow-spreading ridge, In I. G. Gass, S. J. Lippard and A. W. Shelton (eds.),Ophiolites and Oceanic Lithosphere, Geol. Soc. London,Special Publication 13, 101–111.

    Google Scholar 

  • Whitehead, J., Dick, H. J. B., and Schouten, H., 1984, A mechanism for magmatic accretion under spreading centers,Nature 312, 146–148.

    Google Scholar 

  • Zervas, C. E., Lin, J., and Rona, P., 1990, Asymmetric V-shaped gravity stripes at the Mid-Atlantic Ridge 26° N (abstract),Eos Trans. AGU 71, 1572.

    Google Scholar 

  • Zonenshain, L. P., Kuzmin, M. I., Lisitsin, A. P., Bogdanov,, Y. A., and Baranov, B. V., 1989, Tectonics of the Mid-Atlantic Rift valley between the TAG and MARK areas (26–24° N): Evidence for vertical tectonism,Tectonophysics 159, 1–23.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. School of Oceanography, University of Washington, 98195, Seattle, WA, USA

    Jean-Christophe Sempéré & Holly S. Brown

  2. Department of Geology and Geophysics, Woods Hole Oceanographic Institution, 02543, Woods Hole, MA, USA

    Jian Lin, Hans Schouten & G. M. Purdy

Authors
  1. Jean-Christophe Sempéré
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jian Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Holly S. Brown
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Hans Schouten
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. G. M. Purdy
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sempéré, JC., Lin, J., Brown, H.S. et al. Segmentation and morphotectonic variations along a slow-spreading center: The Mid-Atlantic Ridge (24°00′ N– 30°40′ N). Mar Geophys Res 15, 153–200 (1993). https://doi.org/10.1007/BF01204232

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01204232

Key words

Search

Navigation