Crustal structure of the Iceland-Faeroe Ridge
Article Sidebar
Vols. 1-18 (1924-1944), ISSN 0044-2801
Main Article Content
Abstract
Knowledge of the crustal structure of the Iceland-Faeroe Ridge is based on results from the North Atlantic Seismic Project of 1972 supplemented by earlier short refraction lines and reflection, gravity and magnetic surveys. The main 5. 7 km/s upper crustal layer is locally overlain by lower velocity layers of variable thickness. The upper crust is interpreted as being predominantly basaltic, comprising lavas, regions of pyroclastic rock and intrusives including ring complexes. A 6.7 km/s lower crustal layer underlies the upper crust at a depth of between about 4 and 8 km along the Ridge; this layer is present also beneath the Icelandic shelf but not beneath the Faeroe shelf. A deeper 7.8 km/s refractor interpreted as the Moho occurs at about 30-35 km depth beneath the south-eastern part of the Ridge, shallowing to about 28 km towards the north-western end of it. A significant increase in velocity with depth within the main 6.7 km/s layer has not been detected but may occur, in which case the Moho would be somewhat deeper. The seismic crustal results are consistent with a gravity profile across the Ridge, which indicates approximate Airy isostatic equilibrium. The crust beneath the Ridge, which is of a thickness more typical of the continents than the oceans, is believed to have been formed by sea-floor spreading during the period 55 to 40 Ma ago.
ARK: https://n2t.net/ark:/88439/y051071
Permalink: https://geophysicsjournal.com/article/80
Article Details
References
Bott, M.H.P. (1974) Deep structure, evolution and origin of the Icelandic Transverse Ridge. In: L. Kristjansson (ed.) Geodynamics of Iceland and the North Atlantic area, 33-47. D. Reidel, Dordrecht
Bott, M.H.P., Browitt, C.W.A., Stacey, A.P. (1971) The deep structure of the Iceland-Faeroe Ridge. Mar. Geophys. Res. 1:328-351
Bott, M.H.P., Ingles, A. (1972) Matrix methods for joint interpretation of two-dimensional gravity and magnetic anomalies with application to the Iceland-Faeroe Ridge. Geophys. J. Roy. Astron. Soc. 30:55-67
Bott, M.H.P., Nielsen, P.H., Sunderland, J. (1976) Converted P-waves originating at the continental margin between the IcelandFaeroe Ridge and the Faeroe Block. Geophys. J. Roy. Astron. Soc. 44:229-238
Fleischer, U. (1971) Gravity surveys over the Reykjanes Ridge and between Iceland and the Faeroe Islands. Mar. Geophys. Res. 1:314-327
Fleischer, U., Holzkamm, F., Vollbrecht, K., Voppel, D. (1974) Die Struktur des Island-Fiiroer-Riickens aus geophysikalischen Messungen. Dtsch. Hydrogr. Z. 27:97-113
Grnnlie, G., Talwani, M. (1978) Geophysical atlas of the Norwegian Greenland Sea. VEMA Research Series IV, Lamont-Doherty Geological Observatory, USA
Haigh, B.I.R. (1973) North Atlantic oceanic topography and lateral variations in the upper mantle. Geophys. J. R. Astron. Soc. 33:405-420
Hinz, K., Moe, A. (1971) Crustal structure in the Norwegian Sea. Nature Phys. Sci. 232:187-190
Ingles, A.D. (1971) The interpretation of magnetic anomalies between Iceland and Scotland. University of Durham Ph.D. Thesis, pp. 152
Johnson, G.L., Tanner, B. (1972) Geophysical observations on the Iceland-Faeroe Ridge. Jokull 21:45-52
O'Brien, P.N.S. (1968) Lake Superior crustal structure - a reinterpretation of the 1963 seismic experiment. J. Geophys. Res. 73:2669-2689
Palmason, G. (197l) Crustal structure of Iceland from explosion seismology. Soc. Sci. lslandica 40, pp. 187
Talwani, M., Udintsev, G. et al. (1976) Initial Reports of the Deep Sea Drilling Project 38:1256. U.S. Government Printing Office , Washington
Vogt, P.R. (1972) The Faeroe-Iceland-Greenland aseismic ridge and the western boundary undercurrent. Nature 239:79-81
Zverev, S.M., Kosminskaya, J.P., Krasilschikova, G.A., Mikhota, G.G. (1975) Deep structure of Iceland and lceland-Faeroes-Shetland region from results of seismic studies. Bull. MOIP Otd. Geol. Vol. L 3:99-115