Skip to main content
SpringerLink
Log in
Book cover

Structure and Development of the Greenland-Scotland Ridge pp 31–61Cite as

Crust and Upper Mantle Beneath Iceland

  • Chapter

Part of the book series: Nato Conference Series ((MARS,volume 8))

Abstract

Except for greater thickness and more pronounced lateral variations the Icelandic crust is very similar to the crust beneath the Reykjanes Ridge. Layer 3 can be traced without interruption from the 10 m.y. old oceanic crust on the southeastern flank of the ridge through Iceland. It exists also beneath the eastern neo- volcanic zone which is supposed to be the present spreading axis. Wide-angle reflection surveys across the active volcanic zones and the adjacent plateau basalts have given a detailed picture of the crust. The cross sections bear a certain resemblance to the crustal structure deduced from geological observations in Eastern Iceland. The dip of refractors and reflectors toward the axial zone and the absence of reflecting horizons below 8 km depth in the central part of the zone, support the predictions of models of crustal accretion mechanism. The episode of crustal rifting in the NE Iceland axial zone, which started in 1975 and still continues, has demonstrated how intimately the rifting is related to episodic magmatic processes at central volcanoes.

The subcrustal structure below Iceland is fundamentally different from the one below the southeastern flank of the Reykjanes Ridge. The Icelandic crust is underlain by low P-wave velocity (7.0 to 7.6 km/s) material down to depths greater than 50 km which is interpreted as mantle material in the state of partial fusion. This anomalous mantle seems to form a diapiric updoming of the astenosphere much broader than is likely beneath mid-ocean ridges proper. Magnetotelluric soundings indicate a low resistivity layer at the base of the crust. The depth to this layer is about 10 km beneath the axial rift zone but increases to about 17 km below the Tertiary basalts east and west. S-waves generally propagate in the crust beneath the axial rift zone to 10 km depth. At greater depth high P- to S-velocity ratio and attenuation of S-waves support the magneto- telluric evidence for partially molten basalt at the base of the crust, not only under the axial rift zone, but under the whole of Iceland.

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

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   84.99
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD   109.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  • Angenheister, G., H. Gebrande, H. Miller, W. Weigel, P. Goldflam, W. Jacoby, G. Palmason, S. Bjornsson, P. Einarsson, S. Zverev, B. Loncarevic, S. Solomon, 1979: First results from the Reykjanes Ridge Iceland Seismic Project 1977. Nature 279, 56–60.

    Article  ADS  Google Scholar 

  • Angenheister G., et al., 1980: Reykjanes Ridge Iceland Seismic Experiment (RRISP 77). J. Geophys. 47, 228–238.

    Google Scholar 

  • Båth, M., i960: Crustal structure of Iceland. J. Geophys. Res. 65, 1793–1807.

    Google Scholar 

  • Beblo, M., and A. Bjornsson, 1978: Magnetotelluric investigation of the lower crust and upper mantle beneath Iceland. J. Geophys. 45, 1–16.

    Google Scholar 

  • Beblo, M., and A. Bjornsson, 1980: A model of electrical resistivity beneath NE Iceland, correlation with temperature. J. Geophys. 47, 184–190.

    Google Scholar 

  • Bjornsson, A., K. Saemundsson, P. Einarsson, E. Tryggvason, and K. Gronvold, 1977: Current rifting episode in North Iceland. Nature 266, 318–323.

    Article  ADS  Google Scholar 

  • Bjornsson, A., G. Johnsen, S. Sigurdsson, G. Thorbergsson, and E. Tryggvason, 1979: Rifting of the plate boundary in North Iceland 1975–1978. J. Geophys. Res. 84, 3029–3038.

    Article  ADS  Google Scholar 

  • Bodvarsson, G., 1981. Terrestrial energy currents and transfer in Iceland. Amer. Geophys. Un., Geodynamics Series, in prees.

    Google Scholar 

  • Bott, M.H.P., 1965: The upper mantle beneath Iceland. Geophys. J.R. astron. Soc. 9, 275–277.

    Google Scholar 

  • Bott, M.H.P., 1974: Deep structure, evolution and origin of the Icelandic transverse ridge. In: Geodynamics of Iceland and the North Atlantic Area, L. Kristjansson, ed.: 33–47, Reidel, Dordrecht.

    Chapter  Google Scholar 

  • Bott, M.H.P., and K. Gunnarsson, 1980: Crustal structure of the Iceland-Faeroe Ridge. J. Geophys. 47, 221–227.

    Google Scholar 

  • Bottinga, Y., and C. Allégre, 1976: Geophysical, petrological and geochemical models of the oceanic lithosphere. Tectonophysics 32, 9–59.

    Article  ADS  Google Scholar 

  • Brandsdottir B., and P. Einarsson, 1979: Seismic activity associated with the September 1977 deflation of the Krafla central volcano in NE Iceland. J. Volcanol. Geothermal Res. 6, 197–212.

    Article  ADS  Google Scholar 

  • Dagley, P., R.L. Wilson, J.M. Ade-Hall, G.P.L. Walker, S.E. Haggerty, T. Sigurgeirsson, N.D. Watkins, P.J. Smith, J. Edwards, and R.L. Grasty, 1967: Geomagnetic polarity zones for Icelandic lavas. Nature 216, 25–29.

    Article  ADS  Google Scholar 

  • Einarsson P., 1976: Relative location of earthquakes within the Tjornes Fracture Zone. Soc. Sci. Islandica Greinar 5, 45–60.

    Google Scholar 

  • Einarsson P., 1978: S-wave shadows in the Krafla caldera in NE Iceland, evidence for a magma chamber in the crust. Bull. Volcanol. 41, 1–9.

    Article  Google Scholar 

  • Einarsson, P., 1979: Seismicity and earthquake focal mechanisms along the Mid-Atlantic plate boundary between Iceland and the Azores. Tectonophysics 55, 127–153.

    Article  ADS  Google Scholar 

  • Einarsson, P., F.W. Klein, and S. Bjornsson, 1977: The Borgarfjordur earthquakes in West Iceland 1974. Bull. Seismol. Soc. Am. 67, 187–208.

    Google Scholar 

  • Einarsson, P., and S. Bjornsson, 1979: Earthquakes in Iceland. Jokull 29, 37–43.

    Google Scholar 

  • Einarsson, P., and B. Brandsdottir, 1980: Seismological evidence for lateral magma intrusion during the July 1978 deflation of the Krafla volcano in NE Iceland. J. Geophys. 47, 160–165.

    Google Scholar 

  • Einarsson, P., and B. Brandsdottir, 1980: Seismological evidence for lateral magma intrusion during the July 1978 deflation of the Krafla volcano in NE Iceland. J. Geophys. 47, 160–165.

    Google Scholar 

  • Einarsson, Th., D.M. Hopkins, and R.R. Doell, 1967: The stratigraphy of Tjornes, northern Iceland and the history of the Bering Land Bridge. In: The Bering Land Bridge, D.M. Hopkins, ed.: 312–325, Stanford Univ. Press.

    Google Scholar 

  • Einarsson, Tr., 1954: A survey of gravity in Iceland. Soc. Sci. Isl. Rit 30, 22 pp.

    Google Scholar 

  • Einarsson, Tr., 1957: Magneto-geological mapping in Iceland with the use of a compass. Philos. Mag. (Suppl.); 6, 232–239.

    Google Scholar 

  • Evans, J.R., and I.S. Sacks, 1979: Deep structure of the Iceland Plateau. J. Geophys. Res. 84, 6859–6866.

    Article  ADS  Google Scholar 

  • Evans, J.R., and I.S. Sacks, 1980: Lithospheric structure in the North Atlantic from observations of Love and Rayleigh waves. J. Geophys. Res. 85, 7175–7182.

    Article  ADS  Google Scholar 

  • Francis, T.J.G., 1969: Upper mantle structure along the axis of the Mid-Atlantic Ridge near Iceland. Geophys. J.R. astron. Soc. 17, 507–520.

    Article  Google Scholar 

  • Flovenz, O.G., 1980: Seismic structure of the Icelandic crust above layer three and the relation between body wave velocity and the alteration of the basaltic crust. J. Geophys. 47, 211–220.

    Google Scholar 

  • Gebrande, H., H. Miller, and P. Einarsson, I98O: Seismic structure of Iceland along RRISP-profile I. J. Geophys. 47, 239–249.

    Google Scholar 

  • Girardin, N., and G. Poupinet, 1974: Teleseismic S travel time delay for Mid-Atlantic Ridge earthquakes. Phys. Earth Planet. Inter. 9, 306–313.

    Article  ADS  Google Scholar 

  • Goldflam, P., W. Weigel, and B.D. Loncarevic, 1980: Seismic structure along RRISP-Profile I on the southeast flank of the Reykjanes Ridge. J. Geophys. 47, 250–260.

    Google Scholar 

  • Hermance, J.F., 1973: An electrical model for the sub-Icelandic crust. Geophysics 38, 3–13.

    Article  ADS  Google Scholar 

  • Hermance, J.F. 1981: Crustal genesis in Iceland: Geophysical constraints on crustal thickening with age. Geophys. Res. Lett. 8, 203–206.

    Article  ADS  Google Scholar 

  • Hermance, J.F., and L.R. Grillot, 19T0: Correlation of magnetotelluric, seismic, and temperature data from Soutwest Iceland. J. Geophys. Res. 75, 6582–6591.

    Google Scholar 

  • Hermance, J.F., and L.R. Grillot, 1970: Constraints on temperature beneath Iceland from magnetotelluric data. Phys. Earth Planet. Inter. 8, 1–12.

    Article  ADS  Google Scholar 

  • Hermance, J.F., R.E. Thayer, and A. Bjornsson, 1976: The telluric-magnetotelluric method in the regional assessment of geothermal potential. In: Proc. Second U.N. Symposium on the Development and Use of Geothermal Resources, 2, 1037–1048. U.S. Gov. Printing Office, Washington D.C. 201402.

    Google Scholar 

  • Jakobsson, S.P., 1972: Chemistry and distribution pattern of recent basaltic rocks in Iceland. Lithos 5., 365–386.

    Google Scholar 

  • Jacoby, W.R., and N. Girardin, 1980: The evolution of the lithosphere at the southeast flank of Reykjanes Ridge from surface wave data. J. Geophys. 47, 271–277.

    Google Scholar 

  • Jacoby, W.R., A. Bjornsson, and D. Moller, 1980: Iceland: Evolution, Active Tectonics, and Structure. J. Geophys. 47 No. 1–3, 277 pp.

    Google Scholar 

  • Johannesson, H., 1980: Jardlagaskipun og throun rekbelta a Vesturlandi. (Evolution of rift zones in Western Iceland, in Icelandic with English Summary). Natturu- fraedingurinn 50, 13–31.

    Google Scholar 

  • Johnsen, G.V., A. Bjornsson, and S. Sigurdsson, 1980: Gravity and elevation changes caused by magma movement beneath the Krafla caldera, Northeast Iceland, J. Geophys. 47, 132–140.

    Google Scholar 

  • Keen C.E., A. Fricker, M.J. Keen, and L. Blinn, 1980: Reykjanes Ridge crest studied by surface waves with an earthquake pair technique. J. Geophys. 47, 265–270.

    Google Scholar 

  • Klein, F.W., P. Einarsson, and M. Wyss, 1977: The Reykjanes Peninsula, Iceland, earthquake swarm of September 1972 and its tectonic significance. J. Geophys. Res. 82, 865–888.

    Article  ADS  Google Scholar 

  • Kristjansson, L., ed., 1974: Geodynamics of Iceland and the North Atlantic Area, 323 pp., Reidel, Dordrecht.

    Google Scholar 

  • Kristjansson, L., 1979: The shelf area around Iceland. Jokull 29, 3–6.

    Google Scholar 

  • Kristjansson, L., I.B. Fridleifsson, and N.D. Watkins, 1980: Stratigraphy and paleomagnetism of the Esja, Eyrarfjall and Akrafjall mountains, SW Iceland. J. Geophys. 47, 31–42.

    Google Scholar 

  • Lachenbruch, A.H., and J.H. Sass, 1978: Models of an extending lithosphere and heat flow in the Basin and Range Province. Geol. Soc. Am. Memoir 152, eds: R.B. Smith and G.P. Eaton, 209–250.

    Google Scholar 

  • Long, R.E., and M.G. Mitchell, 1970: Teleseismic P-wave delay time in Iceland. Geophys. J.R. astron. Soc. 20, 41–48.

    Article  Google Scholar 

  • McDougall, I., H. Wensink, 1966: Paleomagnetism and geochronology of the Plio-Pleistocene lavas in Iceland. Earth Planet. Sci. Lett. 1, 232–236.

    Article  ADS  Google Scholar 

  • McDougall, I., N.D. Watkins and L. Kristjansson, 1976: Geochronology and paleomagnetism of a Miocene-Pliocene lava sequence at Bessastadaa, Eastern Iceland. Am. J. Sci. 276, 1078–1095.

    Article  Google Scholar 

  • McDougall, I., K. Saemundsson, H. Johannesson, N.D. Watkins, and L. Kristjansson, 1977: Extension of the geomagnetic polarity time scale to 6.5 m. y.: K-Ar dating geological and paleo- magnetic study of a 3,500 m lava succession in Western Iceland. Geol. Soc. Amer. Bull. 88, 1–15.

    Article  ADS  Google Scholar 

  • McMaster, R.L., J.-G. Schilling, and P.R. Pinet, 1977: Plate boundary within Tjornes Fracture Zone on Northern Iceland’s insular margin. Nature 269, 663–668.

    Article  ADS  Google Scholar 

  • Moller, D., and B. Ritter, 1980: Geodetic measurements and horizontal crustal movements in the rift zone of NE Iceland. J. Geophys. 47, 110–119.

    Google Scholar 

  • Musseit, A.E., J.G. Ross, and I.L. Gibson, 1980: 40Ar/39Ar dates of Eastern Iceland lavas. Geophys. J.R. astr. Soc. 60, 37–52.

    Google Scholar 

  • Palmason, G., 1963: Seismic refraction investigation of the basalt lavas in Northern and Eastern Iceland. Jokull 13, 40–60.

    Google Scholar 

  • Palmason, G., 1971: Crustal structure of Iceland from explosion seismology. Soc. Sci. Isl. Rit 40, 187 pp.

    Google Scholar 

  • Palmason, G., 1973: Kinematics and heat flow in a volcanic rift zone, with application to Iceland. Geophys. J.R. astron,Soc. 33, 451–481.

    Article  Google Scholar 

  • Palmason, G., 198I: Crustal rifting and related thermo-mechanical processes in the lithosphere beneath Iceland. Geologische Rundschau 70, 244–260.

    Google Scholar 

  • Palmason, G., and K. Saemundsson, 1974: Iceland in relation to the Mid-Atlantic Ridge. Ann. Review Earth Planet. Sci. 2, 25–50.

    Article  ADS  Google Scholar 

  • Palmason, G., S. Arnorsson, I.B. Fridleifsson, H. Kristmannsdottir, K. Saemundsson, V. Stefansson, B. Steingrimsson, J. Tomasson, and L. Kristjansson, 1979: The Iceland crust: Evidence from drillhole data on structure and processes. In: Deep Drilling Results in the Atlantic Ocean: Ocean Crust, M. Talwani, C.G. Harrison, D.E. Hayes, eds. Amer. Geophys. Un. Maurice Ewing Series 2, 43–65.

    Chapter  Google Scholar 

  • Packer, R.L., and D.W. Oldenburg, 1973: Thermal model of ocean ridges. Nature Phys. Sci. 242, 137–139.

    Article  ADS  Google Scholar 

  • Saemundsson, K., 1974: Evolution of the axial rifting zone in Northern Iceland and the Tjornes Fracture Zone. Geol. Soc. Am. Bull. 85., 495–504.

    Google Scholar 

  • Saemundsson K., 1978: Fissure swarms and central volcanoes of the neovolcanic zones of Iceland. Geol. J. Spec. Iss. 10, 415–432.

    Google Scholar 

  • Saemundsson, K., 1979: Outline of the geology of Iceland. Jokull 29, 7–28.

    Google Scholar 

  • Saemundsson, K., L. Kristjansson, I. McDougall, and MD. Watkins, 1980: K-Ar dating, geological and paleomagnetic study of a 5-km lava succession in Northern Iceland. J. Geophys. Res. 85, 3628–3646.

    Article  ADS  Google Scholar 

  • Saemundsson, K., L. Kristjansson, I. McDougall, and MD. Watkins, 1980: K-Ar dating, geological and paleomagnetic study of a 5-km lava succession in Northern Iceland. J. Geophys. Res. 85, 3628–3646.

    Article  ADS  Google Scholar 

  • Schilling, J.-G., 1973: Iceland mantle plume: Geochemical study of Reykjanes Ridge. Nature 244, 565–571.

    Article  ADS  Google Scholar 

  • Shih, J.S.F., T. Atwater, and M. McNutt, 1978: A near-bottom geophysical traverse of the Reykjanes Ridge. Earth Planet. Sci. Lett. 39, 75–83.

    Article  ADS  Google Scholar 

  • Sigurdsson, H., 1970: Structural origin and plate tectonics of the Snaefellsnes volcanic zone Western Iceland. Earth Planet. Sci. Lett. 10, 129–135.

    Article  ADS  Google Scholar 

  • Sigurdsson, 0., 1980: Surface deformation of the Krafla fissure swarm in two rifting events. J. Geophys. 47, 154 ’ 159.

    Google Scholar 

  • Sigvaldason, G.E., 1974. Basalts from the centre of the assumed Icelandic mantle plume. J. Petrol. 15, 497–524.

    Article  Google Scholar 

  • Spickernagel, H., 1980: Results of height measurements in Northern Iceland 1965/1977. J. Geophys. 47, 120–124.

    Google Scholar 

  • Talwani, M., and O. Eldholm, 1977: Evolution of the Norwegian- Greenland Sea. Bull. Geol. Soc. Am. 88, 969–999.

    Article  Google Scholar 

  • Thayer, R.E., A. Bjornsson, L. Alvarez, and J.F. Hermance, 198I: Magma genesis and crustal spreading in the northern neovolcanic zone of Iceland: telluric-magnetotelluric constraints. Geophys. J.R. astr. Soc. 65, 423–442.

    Google Scholar 

  • Torge, W., and E. Kanngieser, 1980: Gravity and height variations during the present rifting episode in Northern Iceland. J. Geophys. 47, 125–131.

    Google Scholar 

  • Tryggvason, E.,1964: Arrival times of P-waves and upper mantle structure. Bull. Seismol. Soc. Am. 54, 727–736.

    Google Scholar 

  • Tryggvason, E., 1980: Subsidence events in the Krafla area. J. Geophys. 47, 141–153.

    Google Scholar 

  • Tryggvason, E., and M. Båth, 1961: Upper crustal structure of Iceland. J. Geophys. Res. 66, 1913–1925.

    Article  ADS  Google Scholar 

  • Vogt, P.R., 1974: The Iceland phenomenon: Imprints of a hot spot on the ocean crust, and implications for flow below the plates. In: Geodynamics of Iceland and the North Atlantic Area. L. Kristjansson, ed.: 105–126. Reidel, Dordrecht.

    Chapter  Google Scholar 

  • Vogt, P.R., G.L. Johnson, and L. Kristjansson, 1980: Morphology and magnetic anomalies north of Iceland. J. Geophys. 47i, 67–80.

    Google Scholar 

  • Voppel, D., and R. Rudloff, 1980: On the evolution of the Reykjanes Ridge south of 60°N between 40 and 12 million years before present. J. Geophys. 47, 61–66.

    Google Scholar 

  • Walker, G.P.L., 1975: Intrusive sheet swarms and the identity of crustal layer 3 in Iceland. J. Geol. Soc. London 131, 143–161.

    Article  Google Scholar 

  • Ward, P.L., 1971: New interpretation of the geology of Iceland. Geol. Soc. Amer. Bull. 82, 2991–3012.

    Article  ADS  Google Scholar 

  • Watkins, N.D., and G.P.L. Walker, 1977: Magneto-stratigraphy of Eastern Iceland. Amer. J.Sci. 277, 513–584.

    Article  Google Scholar 

  • Zverev, S.M., I.P. Kosminskaya, G.A. Krasilschikova, and G.G. Mikhota, 1976: The crustal structure of Iceland and of the Iceland-Faeroes-Scotland region. Soc. Sci. Isl. Greinar 5, 74–96.

    Google Scholar 

  • Zverev, S.M., I.V. Litvinenko, G. Palmason, G.A. Yaroshevskaya, and N.N. Osokin, 1980a: A seismic crustal study of the axial rift zone in Southwest Iceland. J. Geophys. 47, 202–210.

    Google Scholar 

  • Zverev, S.M., I.V. Litvinenko, G. Palmason, G.A. Yaroshevskaya, N.N. Osokin and M.A. Akhmetjev, 1980b: A seismic study of the rift zone in Northern Iceland. J. Geophys. 47 191–201.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Science Institute, University of Iceland, 107 Reykjavik, Iceland

    Sveinbjorn Bjornsson

Authors
  1. Sveinbjorn Bjornsson
    View author publications

    You can also search for this author in PubMed Google Scholar

Editor information

Editors and Affiliations

  1. University of Durham, Durham, UK

    Martin H. P. Bott

  2. Aarhus University, Aarhus, Denmark

    Svend Saxov

  3. Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York, USA

    Manik Talwani

  4. University of Oslo, Oslo, Norway

    Jörn Thiede

Rights and permissions

Reprints and permissions

Copyright information

© 1983 Springer Science+Business Media New York

About this chapter

Cite this chapter

Bjornsson, S. (1983). Crust and Upper Mantle Beneath Iceland. In: Bott, M.H.P., Saxov, S., Talwani, M., Thiede, J. (eds) Structure and Development of the Greenland-Scotland Ridge. Nato Conference Series, vol 8. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-3485-9_3

Download citation

  • DOI: https://doi.org/10.1007/978-1-4613-3485-9_3

  • Publisher Name: Springer, Boston, MA

  • Print ISBN: 978-1-4613-3487-3

  • Online ISBN: 978-1-4613-3485-9

  • eBook Packages: Springer Book Archive

Publish with us

Policies and ethics

Search

Navigation