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The geology of the Oceanographer Transform: The ridge-transform intersection

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Abstract

Seven dives in the submersible ALVIN and four deep-towed (ANGUS) camera lowerings have been made at the eastern ridge-transform intersection of the Oceanographer Transform with the axis of the Mid-Atlantic Ridge. These data constrain our understanding of the processes that create and shape the distinctive morphology that is characteristic of slowly-slipping ridge-transform-ridge plate boundaries. Although the geological relationships observed in the rift valley floor in the study area are similar to those reported for the FAMOUS area, we observe a distinct change in the character of the rift valley floor with increasing proximity to the transform. Over a distance of approximately ten kilometers the volcanic constructional terrain becomes increasingly more disrupted by faulting and degraded by mass wasting. Moreover, proximal to the transform boundary, faults with orientations oblique to the trend of the rift valley are recognized. The morphology of the eastern rift valley wall is characterized by inward-facing scarps that are ridge-axis parallel, but the western rift valley wall, adjacent to the active transform zone, is characterized by a complex fault pattern defined by faults exhibiting a wide range of orientations. However, even for transform parallel faults no evidence for strike-slip displacement is observed throughout the study area and evidence for normal (dip-slip) displacement is ubiquitous. Basalts, semi-consolidated sediments (chalks, debris slide deposits) and serpentinized ultramafic rocks are recovered from localities within or proximal to the rift valley. The axis of accretion-principal transform displacement zone intersection is not clearly established, but appears to be located along the E-W trending, southern flank of the deep nodal basin that defines the intersection of the transform valley with the rift floor.

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References

  • Atwater, T.: 1979, ‘Constraints from the FAMOUS Area Concerning the Structure of the Oceanic Section’, in Talwani, M., Harrison, C. G., and Hayes, D. E. (eds.), Deep Drilling Results in the Atlantic Ocean: Ocean Crust 2nd Maurice Ewing Memorial Symp., Amer. Geophys. Union 2, 33–42.

  • AumentoF. and LoubatH.: 1971, ‘The Mid-Atlantic Ridge near 45° N, XVI Serpentinized Ultramafic Intrusions’, Can. Jour. Earth Sci. 8, 631–663.

    Google Scholar 

  • BallardR. and vanAndelT. H.: 1977, ‘Morphology and Tectonics of the Inner Rift Valley at Latitude 36° 50′ N on the Mid-Atlantic Ridge’, Geol. Soc. Amer. Bull. 88, 507–530.

    Google Scholar 

  • BallardR., FrancheteauJ., JuteauT., RanginC., and NormarkW.: 1980, ‘East Pacific Rise at 21° N: The Volcanic, Tectonic, and Hydrothermal Processes of the Central Axis’, Earth and Planet. Sci. Letters 55, 1–10.

    Google Scholar 

  • BonattiE.: 1976, ‘Serpentinite Protrusions in the Oceanic Crust’, Earth and Planet. Sci. Letters 32 107–113.

    Google Scholar 

  • BonattiE.: 1978, ‘Vertical Tectonism in Oceanic Fracture Zones’, Earth and Planet. Sci. Letters 37, 369–379.

    Google Scholar 

  • BonattiE. and HamlynP. R.: 1978, ‘Mantle Uplifted in the Western Indian Ocean’, Science 201, 249–251.

    Google Scholar 

  • BonattiE. and HonnorezJ.: 1976, ‘Sections of the Earth's Crust in the Equatorial Atlantic’, J. Geophys. Res. 81: 4104–4116.

    Google Scholar 

  • CAYTROUGH: 1979, ‘Geological and Geophysical Investigations of the Mid-Cayman Spreading Center: Initial Results and Observations’, in Talwani, M., Harrison, C. G. and Hayes, D. E. (eds.), Deep Drilling Results in the Atlantic Ocean: Ocean Crust, 2nd Maurice Ewing Memorial Symp., Amer. Geophys. Union 2, 66–93.

  • CourtillotV., TapponierP., and VaretJ.: 1974, ‘Surface Features Associated with Transform Faults: A Comparison between Observed Examples and Experimental Models’, Tectonophysics 24, 317–329.

    Google Scholar 

  • CraneK.: 1976, ‘The Intersection of the Siquieros Transform Fault and the East Pacific Rise’, Marine Geology 21, 25–46.

    Google Scholar 

  • CraneK. and BallardR.: 1981, ‘Volcanics and Structure of the FAMOUS Narrowgate Rift: Evidence for Cyclic Evolution’, J. Geophys. Res. 86, 5112–5124.

    Google Scholar 

  • CYAMEX Scientific Team: 1981, ‘First Manned Submersible Dives on the East Pacific Rise at 21° N (Project RITA): General Results’, Mar. Geophys. Res. 4, 345–379.

    Google Scholar 

  • DengoC. A. and LoganJ. M.: 1981, ‘Implications of the Mechanical and Frictional Behavior of Serpentinite to Seismogenic Faulting’, J. Geophys. Res. 86, 10771–10782.

    Google Scholar 

  • DetrickR. S., CormierM. N., PrinceR. A., and ForsythD. W.: 1982, ‘Seismic Constraints on the Crustal Structure Within the VEMA Fracture Zone’, J. Geophys. Res. 87, 10, 599–10, 612.

    Google Scholar 

  • DetrickR. S. and PurdyG. M.: 1980, ‘The Crustal Structure of the Kane Fracture Zone from Seismic Refraction Studies’, J. Geophys. Res. 85 3759–3777.

    Google Scholar 

  • deWitM. J., DutchS., KligfieldR., AllenR., and SternC.: 1977, ‘Deformation, Serpentinization, and Emplacement of a Dunite Complex, Gibbs Island, South Shetland Islands: Possible Fracture Zone Tectonics’, J. Geol. 85, 745–762.

    Google Scholar 

  • DickH. J. B.: 1977, ‘Partial melting in the Josephine Peridotite I: The Effect on Mineral Composition and its Consequences for Geobarometry and Geothermometry’, Amer. J. of Sci. 227, 801–832.

    Google Scholar 

  • ElthonD., CaseyJ., CaseyG. F., and KomerS.: 1982, ‘Mineral Chemistry of Ultramafic Cumulates From the North Arm Mountain Massif of the Bay of Islands Ophiolite: Evidence for High-Pressure Crystal Fractionation of Oceanic Basalts’, J. Geophys. Res. 87, 8717–8734.

    Google Scholar 

  • FoxP. J.: 1978, ‘The Effect of Transform Faults on the Character of the Oceanic Crust’, Geol. Soc. Amer. Abs. with Prog. 7, 403.

    Google Scholar 

  • Fox, P. J., Detrick, R. S., and Purdy, G. M.: 1980, ‘Evidence for Crustal Thinning near Fracture Zones: Implications for Ophiolites’, in Panayiotou, A. (ed.), Proceedings of the International Ophiolite Symp. Cyprus, Geol. Surv. Dept. 161–168.

  • Fox, P. J. and Gallo, D. G.: 1984, ‘A Tectonic Model for Ridge-Transform-Ridge Plate Boundaries: Implications for the Structure of the Lithosphere’, Tectonophysics 104 (in press).

  • FoxP. J., LowrieA., and HeezenB. C.: 1969, ‘Oceanographer Fracture Zone’, Deep-Sea Res. 16, 55–66.

    Google Scholar 

  • FoxP. J., SchreiberE., RowlettH., and McCamyK.: 1976, ‘The Geology of the Oceanographer Fracture Zone: A Model for Fracture Zones’, J. Geophys. Res. 81, 4117–4128.

    Google Scholar 

  • Fox, P. J., Schroeder, F., Moody, R. M., and Pitman, W. C., III: 1983, ‘The Morphotectonic Character of the Oceanographer Fracture Zone’, Mar. Geophys. Res. (under review.)

  • FrancheteauJ., ChoukrouneP., HekinianR., LePichonX., and NeedhamD.: 1976, ‘Oceanic Fracture Zones do not Provide Deep Sections into the Crust’, Can. J. Earth Sci. 13, 1223–1235.

    Google Scholar 

  • FrancisT. G.: 1981, ‘Serpentinization Faults and their Role in the Tectonics of Slow-Spreading Ridges’, J. Geophys. Res. 86, 11616–11622.

    Google Scholar 

  • GalloD. G. and FoxP. J.: 1979, ‘The Thermo-Evolution of Oceanic Crust and Lithosphere Proximal to Transform Boundaries’, Geol. Soc. Amer., Abs. with Progs. 11, 429.

    Google Scholar 

  • GalloD. G., RosencrantzE. R., and RowleyD. B.: 1980, ‘Oblique Structures at Ridge-Transform Intersections: Implications for Ridge Dynamics and Pole Determinations’, Trans. Amer. Geophys. Union EOS 61, 358.

    Google Scholar 

  • HamlynP. R. and BonattiE.: 1980, ‘Petrology of Mantle-Derived Ultramafics from the Owen F.Z., NW Indian Ocean: Implications for the Nature of Oceanic Upper Mantle’, Earth Planet. Sci. Letters 48, 65–79.

    Google Scholar 

  • KarsonJ. and DeweyJ.: 1978, ‘Coastal Complex, Western Newfoundland, an Early Ordovician Oceanic Fracture Zone’, Geol. Soc. Amer. Bull. 89, 1037–1049.

    Google Scholar 

  • KarsonJ. and DickH.: 1983, ‘Tectonics of Ridge- Transform Intersections at the Kane Fracture Zone’, Mar. Geophys. Res. 6, 51–98.

    Google Scholar 

  • KarsonJ. DickH. J. B., BryanW. B., and ThompsonG. A.: 1980, ‘Tectonics of Ridge-Transform Intersections at the Kane Fracture Zone’, Geol. Soc. Amer., Abs. with Progs. 12, 458.

    Google Scholar 

  • KarsonJ., ElthonD. E., and DeLongS. E.: 1983, ‘Ultramafic Intrusions in the Lewis Hills Massif, Bay of Islands Ophiolite Complex, Newfoundland: Implications for Igneous Processes at Oceanic Fracture Zones’, Geol. Soc. Amer. Bull. 94, 15–29.

    Google Scholar 

  • Karson, J. and Kidd, W.: ‘Cleavage in Chalks from the Oceanographer Fracture Zone’, (in prep.)

  • LonsdaleP.: 1978, ‘Near-bottom Reconnaissance of a Fast-Slipping Transform Fault Zone at the Pacific-Nazca Plate Boundary’, J. Geol. 86, 451–472.

    Google Scholar 

  • MacdonaldK. C., KastensK., MillerS., and SpiessF. N.: 1979, ‘Deep-Tow Studies of the Tamayo Transform Fault’, Mar. Geophys. Res. 4, 37–70.

    Google Scholar 

  • MenardH. W. and AtwaterT.: 1968, ‘Changes in the Direction of Sea Floor Spreading’, Nature 219, 463–467.

    Google Scholar 

  • MooresE. M. and VineJ. F.: 1971, ‘The Troodos Massif, Cyprus and Other Ophiolites as Oceanic Crust: Evaluation and Implications’, Trans. Roy. Soc. London A268, 443–466.

    Google Scholar 

  • Otter Scientific Team: 1980, ‘The Oceanographer Transform: Submersible and Deep-Towed Camera Investigations’, EOS 60, 1105.

    Google Scholar 

  • OTTER Scientific Team: ‘The Geology of the Oceanographer Transform: The Transform Domain’, Mar. Geophys. Res. (in prep.)

  • Phillips, J. D. and Fleming, H. S.: 1978, ‘Multi-Beam Sonar Study of the Mid-Atlantic Rift Valley, 36°–37° N: FAMOUS’, Geol. Soc. Amer. Map Series 19.

  • PhillipsJ. D., FlemingH. S., FedenR. H., KingW. E., and PerryR. K.: 1975, ‘Aeromagnetic Study of the Mid-Atlantic Ridge Near the Oceanographer Fracture Zone’, Geol. Soc. Amer. Bull. 86, 1348–1357.

    Google Scholar 

  • RaleighC. B. and PattersonM. S.: 1965, ‘Experimental Deformation of Serpentinite and its Tectonic Implications’, J. Geophys. Res. 76, 3965–3985.

    Google Scholar 

  • ReidelW.: 1929, ‘Zur Mechanik Geologischer Brucherscheinungen’, Centralbl. fur Mineral. Geol. of Pal. 1929 B, 354–368.

    Google Scholar 

  • RISE Project Group: 1980, ‘East Pacific Rise: Hot Springs Geophysical Experiments’, Science 207, 1421–1433.

    Google Scholar 

  • RonaP. A.: 1980, ‘TAG Hydrothermal Field: Mid-Atlantic Ridge Crest at Latitude 26° N’, J. Geol. Soc. London 137, 385–402.

    Google Scholar 

  • RowlettH.: 1981, ‘Seismicity at Intersections of Spreading Centers and Transform Faults’, J. Geophys. Res. 86, 3815–3820.

    Google Scholar 

  • Schroeder, F. W.: 1977, ‘A Geophysical Investigation of the Oceanographer Fracture Zone and the Mid-Atlantic Ridge in the Vicinity of 35° N’, Ph.D. Diss Columbia Univ., 450 pp.

  • SclaterJ. G., DickH., NortonI. O., and WoodroffeD.: 1978, ‘Tectonic Structure and Petrology of the Antarctic Plate Boundary Near the Bouvet Triple Junction’, Earth and Planet. Sci. Letters 37, 393–400.

    Google Scholar 

  • SearleR. C.: 1979, ‘Side-Scan Sonar Studies of North Atlantic Fracture Zones’, J. Geol. Soc. London 136, 283–293.

    Google Scholar 

  • SearleR. C. and LaughtonA. S.: 1977, ‘Sonar Studies of the Mid-Atlantic Ridge and Kurchatov Fracture Zone’, J. Geophys. Res. 82, 5313–5328.

    Google Scholar 

  • SinhaM. C. and LoudenK. E.: 1983, ‘The Oceanographer Fracture Zone: I Crustal Structure from Seismic Refraction Studies’, Geophys. J. Roy. Astron. Soc., 75, 713–736.

    Google Scholar 

  • SleepN. H. and BiehlerS.: 1970, ‘Topography and Tectonics at the Intersections of Fracture Zones and Central Rifts’ J. Geophys. Res. 75, 2748–2752.

    Google Scholar 

  • StroupJ. B. and FoxP. J.: 1981, ‘Geologic Investigations in the Cayman Trough: Evidence for Thin Crust along the Mid-Cayman Rise’, J. Geol. 89, 395–420.

    Google Scholar 

  • Tamayo Scientific Team: 1984, ‘Tectonics at the Intersection of the East Pacific Rise with Tamayo Transform Fault’, Mar. Geophys. Res. 6, 159–185 (this issue).

    Google Scholar 

  • TchalenkoJ. S.: 1970, ‘Similarities Between Shear Zones of Different Magnitudes’, Geol. Soc. Amer. Bull. 81, 1625–1640.

    Google Scholar 

  • TchalenkoJ. S. and AmbraseysN. M.: 1972, ‘Structural Analysis of the Dasht-e-Bayaz (Iran) Earthquake Fractures’, Geol. Soc. Amer. Bull. 81, 41–60.

    Google Scholar 

  • TempleD. G., ScottR. B. and RonaP. A.: 1979, ‘Geology of a Submarine Hydrothermal Field, Mid-Atlantic Ridge, 25° N Latitude’, J. Geophys. Res. 84, 7453–7466.

    Google Scholar 

  • WhitmarshR. B. and LaughtonA. S.: 1976, ‘A Long-Range Sonar Study of the Mid-Atlantic Ridge Crest Near 37° N (FAMOUS area) and its Tectonic Implications’, Deep-Sea Res. 23, 1005–1023.

    Google Scholar 

  • WilcoxR., HardingT., and SealyD. R.: 1973, ‘Basic Wrench Tectonics’, Amer. Assoc. Petrol. Geol. Bull. 57, 74–96.

    Google Scholar 

  • WilliamsC. A., LoudenK. E., and TannerS. J.: 1984, ‘The Western Intersection of Oceanographer Fracture Zone with the Mid-Atlantic Ridge’, Mar. Geophys. Res. 6, 143–158 (this issue).

    Google Scholar 

  • WilsonJ. T.: 1965, ‘A New Class of Faults and their Bearing on Continental Drift’, Nature 207, 343–347.

    Google Scholar 

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Authors and Affiliations

  1. Woods Hole Oceanographic Institution, 02543, Woods Hole, MA, USA

    J. A. Karson

  2. Graduate School of Oceanography, University of Rhode Island, 02882, Narragansett, RI, USA

    P. J. Fox, H. Sloan & D. G. Gallo

  3. Lamont-Doherty Geological Observatory, 10964, Palisades, NY, USA

    K. T. Crane, E. Bonatti, D. J. Fornari, P. Hamlyn & R. Sartori

  4. Dept. of Geol. Sciences, SUNY at Albany, 12222, Albany, NY, USA

    W. S. F. Kidd & J. B. Stroup

  5. Dept. of Geology, University of Houston, 77004, TX, USA

    D. Elthon & J. F. Casey

  6. C.O.B., B.P. 337, Brest, France

    D. Needham

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  1. J. A. Karson
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  2. P. J. Fox
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  3. H. Sloan
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  4. K. T. Crane
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  5. W. S. F. Kidd
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  6. E. Bonatti
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  8. D. J. Fornari
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  9. D. Elthon
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  10. P. Hamlyn
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  12. D. G. Gallo
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OTTER (Oceanographer Tectonic Research Team)

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OTTER (Oceanographer Tectonic Research Team)., Karson, J.A., Fox, P.J. et al. The geology of the Oceanographer Transform: The ridge-transform intersection. Mar Geophys Res 6, 109–141 (1984). https://doi.org/10.1007/BF00285956

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