Abstract
Maps of the main structures and the degree of geothermal studies of the Azores-Gibraltar and Iceland regions are constructed. Computer modeling of the coefficient of velocity of thermal subsidence into the asthenosphere of the Azores segment of the Mid-Atlantic Ridge is performed. According to the results of modeling, this velocity exceeds the mean velocity of thermal subsidence of the mid-ocean ridges of the world ocean by a factor of ∼ 1.5. The high velocity of subsidence of the Azores segment of the ridge is caused by the influence of the hot substance of the plume on the process of subsidence. The distributions of the heat flow in the Horseshoe basin, Alboran Sea, and southern part of the Iberian Peninsula are analyzed. A zone of increased heat flow and seismicity, extending from the Madeira-Torre Ridge through the Horseshoe basin, and farther to the east through the southern parts of Spain and France, is identified for the first time. The identified geothermal zone marks the northern branch of the diffuse boundary between the Eurasian and African plates. In the region of the Alpine chain, this zone joins the southern boundary between the Eurasian and African plates, which runs along the northern part of Africa and the Apennine Peninsula. The European and African plate boundaries outline the identified Western-Mediterranean plate, which mainly consists of the oceanic and thinned continental lithospheres of the Algerian-Provence and Tyrrhenian basins.
Similar content being viewed by others
References
I. A. Basov, N. A. Bogdanov, M. Komas, et al., “Recent Sediments, Heat Flow, and Gravity Field in the Alboran Sea (Western Mediterranean),” Dokl. Akad. Nauk 338(2), 229–234 (1994).
J. F. Borges, M. Bezzeghoud, E. Buforn, et al., “The 1980, 1997 and 1998 Azores Earthquakes and Some Seismo-Tectonic Implications,” Tectonophysics 435, 37–54 (2007).
E. Buforn, A. Ud’y-as, and M. Colombas, “Seismicity, Source Mechanisms and Seismotectonics of the Azores-Gibraltar Plate Boundary,” Tectonophysics 152, 89–118 (1988).
A. F. Byakov and V. G. Kaz’min, “Spatial Variations in the Velocities of Subsidence of the Mid-Atlantic Ridge Flanks in the Central Atlantic,” Okeanologiya 42(3), 434–441 (2002).
A. G. Camacho, F. G. Montesinos, and R. Vieira, “A Three-Dimensional Gravity Inversion Applied to Sao Miguel Island (Azores),” J. Geophys. Res. 102(B.4.), 7717-77–30 (1997).
R. L. Carlson and H. P. Johnson, “On Modeling the Thermal Evolution of the Oceanic Upper Mantle: An Assessment of the Cooling Plate Model,” J. Geophys. Res. 99(B.2), 3201–3214 (1994).
J. Escartin, M. Cannat, G. Pouliquen, et al., “Crustal Thickness of V-Shaped Ridges South of Azores: Interaction of the Mid-Atlantic Ridge (36°–39°N) and the Azores Hot Spot,” J. Geophys. Res. 106(B.10), 21719–21735 (2001).
Evolution of the Tethys, Ed. by A. Monin and X. Le Pichon, Tectonophysics 123(1/4), 315 p. (1986).
R. M. S. Fernandes, Present-Day Kinematics at the Azores-Gibraltar Plate Boundary as Derived from GPS Observations (University of Coimbra, Portugal, Ph.Thesis, 2004).
J. Geldmacher, K. Hoernle, A. Klugel, et al., “Origin and Geochemical Evolution of the Madeira-Tore Rise (Eastern North Atlantic),” J. Geophys. Res. 111(B.09206) (2006).
Yu. S. Genshaft and M.V. Kononov, Iceland: Deep Structure and Intrusive Magmatism (GEOS, Moscow, 1999) [in Russian].
S. Goes, W. Spakman, and H. Bijwaard, “A Lower Mantle Source for Central European Volcanism,” Science 286, 1928–1931 (1999).
A. Ya. Gol’mshtok, “On the Influence of Sedimentation on the Deep Heat Flow,” Okeanologiya 19(B.6), 1133–1138 (1979).
A. F. Grachev, “Mantle Plumes,” in Problems of Global Geodynamics (Ed. D. V. Rundquist, GEOS, Moscow, 2000), pp. 69–103 [in Russian].
N. L. Grimison and W.-P. Chen, “The Azores-Gibraltar Plate Boundary: Focal Mechanisms, Depths of Earthquakes, and Their Tectonic Implications,” J. Geophys. Res. 91(B.2), 2029–2047 (1986).
N. Hayward, A. B. Watts, G. K. Westbrook, et al., “A Seismic Reflection and GLORIA Study of Compressional Deformation in the Gorrindge Bank Region, Eastern North Atlantic,” Geophys. J. Int. 138, 831–850 (1999).
International Geological-Geophysical Atlas of the Atlantic Ocean (Ed. G. B. Udintsev, MOC (UNESCO), Mingeo SSSR, AN SSSR, GUGK SSSR, Moscow, 1989–1990) [in Russian].
S. M. Jones, “Test of a Ridge-Plume Interaction Model Using Oceanic Crustal Structure around Iceland,” Earth Planet. Sci. Lett. 208, 205–218 (2003).
V. E. Khain, Tectonics of Continents and Ocean (2000) (Nauchnyi Mir, Moscow, 2001) [in Russian].
S. Le Douran and B. Parsons, “A Note on the Correction of Ocean Floor Depth for Sediment Loading,” J. Geophys. Res. 87, 4715–4722 (1982).
N. Lourenco, J. Miranda, J. Luis, et al., “Morpho-Tectonic Analysis of the Azores Volcanic Plateau from a New Bathymetric Compilation of the Area,” Marine Geophys. Res. 20, 141–156 (1998).
J. F. Luis, J. M. Miranda, A. Galdeano, and P. Patriat, “Constraints on the Structure of the Azores Spreading Center from Gravity Data,” Marine Geophys. Res. 20, 157–170 (1998).
J. Madeira and A. Ribeiro, “Geodynamic Models of the Azores Triple Junction: a Contribution from Tectonics,” Tectonophysics 184, 405–415 (1990).
B. Parsons and J. C. Sclater, “An Analysis of the Variation of Ocean Floor Bathymetry and Heat Flow with Age,” J. Geophys. Res. 82(5), 803–827 (1977).
B. G. Polyak, M. Fernandez, M. D. Khutorskoy, et al., “Heat Flow in the Alboran Sea, Western Mediterranean,” Thectonophysics 263, 191–218 (1996).
B. G. Polyak, V. I. Kononov, and M. D. Khutorskoi, “Heat Flow and the Structure of the Lithosphere of Iceland in the Light of New Data,” Geotektonika, No. 1, 111–119 (1984).
G. M. Purdy, “The Eastern End of the Azores-Gibraltar Plate Boundary,” Geophys. J. Roy. Astron. Soc. 43, 123–150 (1975).
P. A. Rona, The Central North Atlantic Basin and Continental Margins (Environ. Res. Lab. No. 3, Miami, Florida 33349, 1980).
J.-G. Schilling, “Geochemical and Isotopic Variation along the Mid-Atlantic Ridge from 79°–0°N,” in The Geology of North America. V. M.—The Western North Atlantic Region. The Geological Society of America, pp. 137–156 (1986).
J.-G. Schilling, M. Zajac, R. Evans, et al., “Petrologic and Geochemical Variations along the Mid-Atlantic Ridge from 29°–73°N,” Am. J. Sci. 283, 510–586 (1983).
R. Searle, “Tectonic Pattern of the Azores Spreading Centre and Triple Junction,” Earth Planet. Sci. Lett. 51, 415–434 (1980).
T. Simkin, R. I. Tilling, J. N. Taggart, et al., This Dynamic Planet. World Map of Volcanoes, Earthquakes, and Plate Tectonics. Scale 1: 30000000 (Smithsonian Institution US Geological Society, 1989).
G. M. Stampfli and G. D. Borel, “A Plate Tectonic Model for the Paleozoic and Mesozoic Constrained by Dynamic Plate Boundaries and Restored Synthetic Oceanic Isochrones,” Earth Planet. Sci. Lett. 196, 17–33 (2002).
Terrestrial Heat Flow in Europe (Ed. V. Chermak, L. Rybash, B.: Springer, 1979).
The Global Seismic Hazard Assessment Program (GSHAP) 1992–1999, Ann. Geof. 42(6), 1230 p.
V. P. Trubitsyn and V. V. Rykov, “Mantle Convection with Floating Continents,” in Problems of Global Geodynamics (Ed. D. V. Rundkvist, GEOS, Moscow, 2000), pp. 7–28 [in Russian].
A. Udias, “Seismicity of the Mediterranean Basin,” in Geological Evolution of the Mediterranean Basin (Springer, New York, 1985), pp. 55–63.
E. V. Verzhbitsky, “Specific Features of the Structure of the Eastern Part of the Azores-Gibraltar Fault Zone (Atlantic Ocean),” Geol. Razvedka, No. 6, 19–25 (2001).
E. V. Verzhbitsky, “Geothermal Regime and Age of the Oceanic and Continental Lithospheres (using as Examples the Ionian and Adriatic Basins of the Mediterranean Sea),” Okeanologiya 41(1), 132–137 (2001).
E. V. Verzhbitsky, Geothermal Regime and Seafloor Tectonics along the Alpine-Himalayan Belt (Nauka, Moscow, 1996) [in Russian].
E. V. Verzhbitsky, M. V. Kononov, A. F. Byakov, et al., “Specific Features of the Evolution of the Lithosphere of the Hawaiian-Emperor System of Ridges (Pacific Ocean) from Geophysical Data,” Geotektonika, No. 6, 73–89 (2006).
E. V. Verzhbitsky and M. V. Kononov, “Heat Flow and Kinematics of Plate Interaction in the West Mediterranean,” Okeanologiya 43(6), 906–918 (2003).
E. V. Verzhbitsky and V. G. Zolotarev, “Heat Flow and the Eurasian-African Plate Boundary in the Eastern Part of the Azores-Gibraltar Fracture Zone,” Geodynamics 11, 267–273 (1989).
P. R. Vogt and W. Y. Jung, “The Terceira Rift as Hyper-Slow, Hotspot-Dominated Oblique Spreading Axis: A Comparison with Other Slow-Spreading Plate Boundaries,” Earth Planet. Sci. Lett. 218, 77–90 (2004). doi: 10.1016/S0012-821X(03)00627-7.
T. Yang, Y. Shen, van der Lee S., et al., “Upper Mantle Structure beneath the Azores Hotspot from Finite-Frequency Seismic Tomography,” Earth Planet. Sci. Lett. 250, 11–26 (2006).
Author information
Authors and Affiliations
Additional information
Original Russian Text © E.V. Verzhbitskii, M.V. Kononov, A.F. Byakov, O.V. Grinberg, 2010, published in Fizika Zemli, 2010, No. 10, pp. 72–83.
Rights and permissions
About this article
Cite this article
Verzhbitskii, E.V., Kononov, M.V., Byakov, A.F. et al. Specific features of the genesis of the Azores-Gibraltar fault zone (North Atlantic). Izv., Phys. Solid Earth 46, 872–882 (2010). https://doi.org/10.1134/S1069351310100071
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1069351310100071